Platinum Metals Review

UK ISSN 0032-1400

PLATINUM METALS REVIEW

A quarterly survey of research on the platinum metals and of developments in their application in industry

VOL. 39 OCTOBER 1995 NO. 4

Contents

Ruthenium, Nitric Oxide and Disease 150

Platinum and Palladium Convert Biofuel By-product 159

Fourth Grove Fuel Cell Symposium 160

Osmium, the Densest Metal Known 164

New Materials for Fuel Cell Systems 165

Microstructure and Properties of Some Dispersion Strengthened Platinum Alloys 167

Modelling Techniques for Catalyst Development 171

Routes to Useful Products and Processes 172

Platinum Metals in Electrochemistry 173

Ruthenium Effect on the Transformation in Equiatomic Titanium-Nickel Alloy 174

Noble Metals Utilised in Drugs and Healthcare 179

Abstracts 180

New Patents 186

Index to Volume 39 191

Communications should be addressed to The Editor, Susan V. Ashton, Plutinum Metals Review Johnson Matthey Publk Limited Company, Hatton Garden, London ECl N 8EE Ruthenium, Nitric Oxide and Disease A NOVEL INORGANIC CHEMISTRY APPROACH TO DRUG DESIGN By S. P. Fricker Johnson Matthey Technology Centre

Recent discoveries in the biological sciences have revealed that nitric oxide has a number of important physiological functions and is also implicated in a number of diseases. This realisation has provided a stimulus for nitric oxide related drug research and development. In this review new work aimed at the development of potential therapeutic use of ruthenium compounds, particularly ruthenium( III) polyaminocarboxylate, JM1226, is presented and discussed in the context of the chemistry and biology of nitric oxide. Based on these studies, prospects for the further development of JM1226 appear promising.

Nitric oxide (nitrogen monoxide, NO) is com- memory, defence against microorganisms and monly viewed as being a toxic environmental tumours, and penile erection, are now known pollutant. This has been the major motivation to be dependent upon the formation of metal- for research into both its chemical reactivity and nitrosyl complexes. A breakdown in the regu- biological activity. Nitric oxide is one of the lation of nimc oxide metabolism has been impli- major emissions from car exhausts and for many cated in a number of diseases, including scientists the co-ordination chemistry of the hypertension, epilepsy, diabetes, arthritis and platinum group metals and nitric oxide is syn- septic shock. onymous with the development of the auto- The Biomedical Technology Group at Johnson mobile catalytic converter. However, new devel- Matthey has made a major contribution to the opments in the biological sciences have now research and development of metal-based drugs, allowed us to look at some of the well known most notably in the field of the platinum anti- chemistry of transition metals and nitric oxide cancer drugs (3,4). Recently, we have adopted from a different perspective. a novel approach to the problem of nitric oxide- mediated disease, by viewing nitric oxide as a Nitric Oxide in Mammalian Cells ligand for transition metals, in particular ruthe- A major conceptual change has taken place in nium. This paper presents the back&ound to the biological sciences following the recent dis- this approach, together with a brief review of covery that nitric oxide is synthesised and the chemistry of nitric oxide and an historical secreted by a number of mammalian cells (1 , account of the discovery of the biological action 2). Nitric oxide has been found to be an essen- of nitric oxide. The role of nitric oxide both in tial component of many physiological processes, maintaining normal function and in the patho- such as the regulation of cardiovascular func- genesis of disease is also reviewed. The mech- tion, signalling between nerves in both the anism by which nitric oxide exerts its biological peripheral and central nervous system and medi- effects is discussed, based upon our knowledge ating host defence against microorganisms and of its chemical reactions in a biological envi- tumour cells. The biological activity of nitric ronment, and the application of this knowledge oxide has been shown to be mediated by the in the search for new drugs to treat nitric oxide- nimosylation of iron in iron-containing proteins. mediated diseases is described. New data from Many fundamental biological processes, such our laboratory are presented, demonstrating as regulation of blood pressure, learning and the potential therapeutic use of ruthenium

Platinum Metals Rev., 1995,39, (4), 150-159 150 Fig. 1 A cross-section through an artery, showing the promesea occurring in an internal endothelid cell and an adjacent muscle cell. Nitric oxide is synth- eeisedinrespnaetoatimulisu& as the neurotransmitter acetylcholine (ACh). Acetylcholine binds to a receptor (R) on the surface of an endothelial cell. This opens an ion channel (I) to allow calcium to enter the cell. This caman increase in intracellular calcium which activates the constitutive nitric oxide synthase (c-NOS). The nitric oxide produced diffuses out of the endothelial cell into the muscle cell. Nitric oxide activates the enzyme guanylate eyclase (GC) which synthesises cyclic guanosine mouophosphate (cGMP). The cGMP in turn activates a series of events leading to muscle relaxation,vasodilationof the blood vessel and a lowering of blood pressure complexes as nitric oxide scavengers in septic metal complexes and this property has been used shock, and possible future developments are dis- to study haem iron in haemoglobin and more cussed in the light of progress made to date. recently the interaction of nitric oxide with metalloproteins in biological environments (6). The Chemistry of Nitric Oxide The co-ordination chemistry of nitric oxide is Nimc oxide is a colourless gas at room tem- similar to that of carbon monoxide, since both perature and is soluble in water. It has an elec- are n-acceptor ligands; however, nimc oxide has tronic configuration of (01)'(01*>'(02,n)'(n*) (5). one more electron than carbon monoxide and The unpaired electron means that nitric oxide this occupies a X* orbital. The existence of metal is formally a radical and is responsible for the nitrosyl complexes has been known for over a unique properties of that molecule. Unlike most century but they have not been so extensively radicals, nitric oxide does not readily form studied as their carbonyl counterparts. One rea- dimers. This is because the unpaired electron son for this is that the M-NO bond (M is metal) cancels out the effect of the bonding electrons, is very stable in most cases, which results in the giving a bond order of 2.5, which in a dimer metal nitrosyls being generally unreactive com- would remain unchanged. pared with M-CO complexes. Nitric oxide can Nimc oxide is very reactive and in the gas phase form three types of metal-nitrosyl complex witlx will react very rapidly with oxygen to form nitro- (i) linear, terminal, M-N-0 groups gen dioxide (NO'). The mixture of nitrogen (ii) bent, terminal, M-N-0 groups and oxides (NOx) emitted from the exhaust of inter- (iii) bridging NO groups. nal combustion engines which are not cleaned Nitric oxide can lose the electron in the n* up by catalytic converters, is of course, a major orbital to form the nitrosonium ion, NO'. This contribution to environmental pollution. Nitric will form linear NO complexes where the oxide is paramagnetic but does not have an elec- ligand is formally NO'. tron paramagnetic resonance (EPR) spectrum In the bent, terminal complexes, having in solution. However, it does form paramagnetic bond angles of 120 to 140°, the ligand can be

Platinum Me& Rev., 1995,39, (4) 151 Macrophage cell Turnour cell Fig. 2 The processes which occur in the blood when a macrophage cell (left) attacks a tumour cell (right). The macrophage cell is an important component of defence against tumour cells. The macrophage is activated by cytokinea, such as interferon-y, (IFN-y). It responds by synthe- sising the inducible nitric oxide iron contaming proteins synthase enzyme (1-NOS). The nitric oxide produd by i-NOS Sl t fnthesis ot diffuses out of the macrophage ] new proteins I/ and into the adjacent target cell, where it kills the target tnmour Turnour cell death cell by inhibiting key enzymes which contain non-haem iron centres. A macrophage cell line, RAW264, has been used at the Johnson Matthey Technology Centre to evaluate new nitric Cytokines e.g IFN-8 oxide scavenging compounds

represented as NO.. This is an oversimplifica- tube, the endothelium, consists of a layer of cells tion of the situation (7,8) but it provides us with called endothelial cells. a useful way of discussing the reactivity of nitric In 1980 Furchgott demonstrated that for oxide with metals. acetylcholine to function as a vasodilator the In subsequent sections we will look at the artery must have an intact endothelium (9). The mechanism by which nitric oxide exerts its bio- implication was that acetylcholine acted on the logical effects, by the nitrosylation of iron endothelial cells, these in turn produced a sec- centres in proteins, and at the application of ond chemical signal which triggered the relax- ruthenium compounds as scavengers of nitric ation of the muscle layer. This chemical was oxide in disease. called endothelium derived relaxing factor (EDRF). Two independent groups (those of The Biology of Nitric Oxide Furchgott and Ignarro) proposed that EDRF The realisation that nitric oxide could have a was actually nitric oxide (2) and in 1987 positive biological function resulted from sev- Ignarro's laboratory and a research group at eral convergent lines of research carried out in the Wellcome laboratories confirmed this laboratories throughout the world (2). hypothesis (10, 1 1). Organonitrate compounds such as glyceryl trinitrate (nitroglycerin) have long been used in Functions of Nitric Oxide Within the Body the treatment of angina. These compounds It is now known that nitric oxide plays a key cause relaxation of arterial blood vessels (vasodi- part in the regulation of blood pressure as a com- lation) and act by releasing nitric oxide. A num- ponent of an integrated control mechanism. ber of compounds which occur naturally in the In 1988 it was found that nitric oxide could body, such as the neurotransmitter acetylcholine also function as a neurotransmitter (1, 2). The (a chemical signalling molecule), also cause two major neurotransmitters in the peripheral vasodilation. Arteries can be thought of as two nervous system are acetylcholine and nora- concentric tubes, see Figure 1. The outer tube drenaline. These chemicals act as messengers consists of muscle which is responsible for con- at nerveherve and nerve/muscle junctions. striction and dilation of the artery. The inner However, some peripheral nerves were known

Platinum Metak Rev., 1995, 39, (4) 152 to use neither noradrenaline (nonadrenergic, ronment, increased during infection. Other NA) nor acetylcholine (noncholinergic, NC), studies had demonstrated that the mechanism and these were named NANC nerves. by which macrophages (one of the cells of the NANC nerves are found in many of the bod- immune system) killed cells was by targeting ily tissues including gastrointestinal tract, res- intracellular iron. This effect was dependent piratory tract, cardiovascular muscle and the upon the presence of L-arginine (an essential urogenital system. Nitric oxide was discovered amino acid) but it could be reproduced by nitric to be the neurotransmitter for NANC nerves. oxide. It was concluded that the macrophages The involvement of nitric oxide in penile erec- were using nitric oxide to kill the target cells, tion has received much attention. This is medi- see Figure 2. ated by NANC nerves which release nitric oxide causing relaxation of the smooth muscle of the Nitric Oxide Synthase (NOS) corpus cavernosum and increased blood flow These findings also enable us to account for leading to penile erection. the biological source of nitric oxide. Nitric oxide Nitric oxide is also a neurotransmitter in the is synthesised in cells by the enzyme nitric oxide brain. Its exact function in the brain is unknown synthase (NOS) which catalyses the oxidation but one hypothesis is that it may be involved in of L-arginine to L-citrulline and nitric oxide, long-term experience and memory. All previ- see Figure 3(a). There are a number of known ously known chemical signalling molecules, such inhibitors of nimc oxide synthase, many of which as neurotransmitters and hormones, were either are substrate analogues of L-arginine, for exam- small organic molecules like acetylcholine, or ple N"-monomethyl-L-arginine (L-NMMA) , peptides and proteins. The discovery that a small, see Figure 3@). These inhibitors have been used diatomic, inorganic molecule is a biological sig- extensively as tools in the study of the biologi- nalling agent has completely changed the way cal action of nitric oxide, as discussed below. in which we now think about the mechanism of The unique enzyme, NOS, has a complex reac- regulation of many vital bodily functions. tion mechanism and many of its details are still The study of the immune response (the body's unknown (13, 14). There are a number of iso- defence against foreign cells such as bacteria, forms of nitric oxide synthase and the simplest viruses and tumours) led to the discovery of yet classification divides them into two main classes: another role for nitric oxide ( 12). It was known the constitutive and the inducible forms. that the urinary excretion of nitrite and nitrate, The constitutive enzyme, c-NOS, as its name which are the end products of the oxidation suggests, is always present in the cell. It is depen- of nitric oxide in an aqueous biological envi- dent upon calcium for its activity and it is

(a)

(b) W H2NYNW; +WzNvN-cH3 I

i" +202 + 2H2O + NO Svnthase Nitric oxide -i"A i" c NH~+ cA NH~+ // \o- \o- 04

Arg i ni ne L- L- Ci t ruII i ne L-NMMA

Fig. 3(a) Nitric oxide synthase (NOS) produces nitric oxide by the oxidation of L-arginine; I (b) NOS can be inhibited by arginine analogues such as N-monomethyl-L-arginine(L-NMMA)

Platinum Metals Rev., 1995, 39, (4) 153 regulated by intracellular calcium concentra- other cells to synthesise i-NOS, which leads to tions. As an example, the neurotransmitter an increase in the concentration of nitric oxide. acetylcholine causes a transient increase in the This has a two-fold effect. First, the toxic lev- calcium concentration in endothelial cells which els of nitric oxide can cause tissue damage. activates c-NOS, leading to a burst of nitric Second, and more important, the nitric oxide oxide production. The local concentration of also causes vasodilation, which leads to a severe nitric oxide produced by c-NOS is low (of the drop in blood pressure and vascular collapse. order of nM) ,which is compatiblewith the func- This situation is made even worse by the fact tion of nitric oxide as a chemical messenger. that such patients also fail to respond to the The second form of the enzyme is the inducible vasoconstrictor drugs which are normally used form, i-NOS. This isoform is calcium inde- to raise blood pressure. The lack of response to pendent and is synthesised by cells, for exam- these drugs is also believed to be due to nitric ple macrophages, in response to external stim- oxide. Septic shock is fatal in more than 50 uli. It is regulated by turning on protein synthesis per cent of cases, therefore the search for new (transcription). The synthesis of i-NOS by drugs that can reduce nitric oxide levels in this macrophages is stimulated by components of and in other diseases is a major challenge for the bacterial cell wall (lipopolysaccharide and medicinal chemists and is a potentially prof- endotoxin) and by cytokines (peptides that reg- itable area for the pharmaceutical industry. ulate the immune response) such as interferon- y. Once i-NOS has begun to produce nitric oxide The Biological Chemistry it will continue to do so for several hours and at of Nitric Oxide concentrations (of the order of pM) that are high Nitric oxide mediates these multiple and enough to be toxic to the target cell. diverse biological events by the nitrosylation of iron. However, the control of biological sys- Diseases Caused by Dysfunction tems at the molecular level is worth consider- in Nitric Oxide Metabolism ing, in order to put our understanding of the Since it is now known that nitric oxide has this biological actions of nitric oxide into a wider multifunctional role in the human body, it is not context. surprising that dysfunctions in nitric oxide A mammalian cell receives an external signal, metabolism have been found in a number of dis- such as a hormone, for example adrenaline, and eases (1, 2). For example, it has been proposed the result of this is seen as a biological event, that an impairment in c-NOS activity in in this case an increase in the metabolism of car- endothelial cells is a contributory factor in essen- bohydrate to provide energy for the “fright, fight tial hypertension. or flight” response. There is a sequence, or path- Hypertension can be treated clinically with way, of intracellular biochemical events between nitric oxide donor drugs, such as the organo- receipt of the external signal and the response. nitrates. An inorganic nitric oxide donor drug, The study of the biochemistry of cell-signalling sodium nitroprusside, is used in emergency pathways is an area of intense activity, but in cases. However, the overproduction of nitric spite of this only some of the steps in the oxide is toxic to the body. The production of sequence are known. excessive, toxic quantities of nitric oxide is a A key step in a number of cell-signalling path- major contributory factor in diseases such as ways is the formation of the second messenger diabetes, arthritis, inflammation, epilepsy and molecule, cyclic guanosine monophosphate septic shock. (cGMP) from guanosine triphosphate (GTP); The disease known as septic shock is caused cGMP then goes on to activate other bio- by very high levels of bacteria circulating in chemical actions in the signalling sequence. the blood. This triggers the immune response, This biochemical reaction (GTP to cGMP) is including the stimulation of macrophages and catalysed by the enzyme guanylate cyclase (GC)

Platinum Metals Rev., 1995, 39, (4) 154 see Figure 1. One of the significant observations understanding of the aqueous chemistry of nitric made in the early stages of the research into oxide in a biological environment. The gas phase nitric oxide was that nitric oxide increased the chemistry of nitric oxide is well documented but activity of guanylate cyclase in the arterial extrapolation to the aqueous phase is mislead- smooth muscle cells. ing. It is now known that nitric oxide reacts with It is notable that this enzyme contains haem oxygen in an aqueous environment to give nitrite (1, 2). Haem is a complex of the tetradentate (16). Nitric oxide will also react with oxy- protoporphyrin ligand with Fe(I1) and is found haemoglobin to give methaemoglobin and in a number of enzymes and the oxygen nitrate. carrier protein haemoglobin. The nature of the oxidation products of nitric oxide is therefore dependent upon the oxygen Nitric Oxide Reactions in the Body status of the environment (6). In venous blood Nitric oxide will form complexes with Fe(I1) nitric oxide is converted primarily to NO;, haem and Fe(III) haem (6,15). In haemoglobin whereas in arterial blood (where oxyhaemo- (Hb) the normal oxidation state is Fe(I1) (d') globin is present) the main product is NO;. and in this case nitric oxide acts as a two elec- These reactions of nitric oxide account for the tron donor to form Hb(Fe(II))NO. The remain- raised levels of nitrate and nitrite seen in patients ing unpaired electron makes the molecule para- with bacterial infections (due to the elevated magnetic, which allows it to be detected by EPR. levels of nitric oxide produced by cells, such This has been exploited in the investigation of as macrophages). the biological properties of nitric oxide. The HbNO can be further oxidised in the presence Nitric Oxide Effects on Tumours of oxygen to methaemoglobin (HbFe(II1)). The toxicity of nitric oxide towards bacteria Nitric oxide will also bind loosely to HbFe(II1) and tumours can also be explained by the for- (d5)and reduce it slowly to Hb(Fe(I1))NO. mation of metal-nitrosyl bonds. In tumour cells Haem-ligand interactions are influenced by the intracellular targets that macrophages attack the local environment provided by the host pro- have been identified (12). Three key proteins tein. The important conditions are hydropho- involved in energy metabolism were shown to bicityhydrophilicity of the surrounding amino be selectively inhibited; these were: aconitase, acids, steric effects and the axial ligands. The complex I and complex II. All contain non-haem latter may be particularly important for the acti- iron as iron-sulphur clusters, for example Fe& vation of guanylate cyclase. It is known that both in aconitase. Nitrosylation of the iron in these oxygen and carbon monoxide bind more strongly enzymes has been demonstrated by EPR. to haem when a basic ligand, histidine in haemo- Ribonucleotidereductase, a controlling enzyme globin, occupies the fifth co-ordination posi- in DNA synthesis, was also inhibited. This tion, whereas nitric oxide binding to haem is enzyme contains an FezOcentre, and the nitro- enhanced when this position is empty. One pos- sylation of this iron centre may be one mecha- sible explanation for the activation of guanylate nism by which nitric oxide inhibits this enzyme. cyclase is that when nitric oxide binds to the iron haem the result is an out-of-plane move- Ruthenium Complexes as ment of the iron to give a haem core similar to Nitric Oxide Scavengers thatofafkeporphyrin(15).Therearestillmany The realisation that nitric oxide is involved questions to be answered concerning the mech- in disease has provided a new focus for phar- anism of activation of guanylate cyclase by nitric maceutical research. The traditional approach oxide, not least the oxidation state of the iron to research by a medicinal chemist is via organic in the haem group of guanylate cyclase. chemistry, and many researchers are at pre- A knowledge of the interaction between nitric sent engaged in investigating the use of inhibitors oxide and haemoproteins is important for our of the nitric oxide synthase enzyme.

Platinum Met& Rev., 1995, 39, (4) 155 0

&O 0 pKa 7.6 [ 'iQOH-

coo- 0 ,to 0 JM 1226 JM 6245 1 NO fast +

Fig. 4 The proposed mechanism for the reaction of K[Ru(Hedta)CI], JM1226, with nitric oxide involves the formation of the aqua complex, [Ru(Hedta)(HIO)], JM6245. This is followed by associative ligand substitution with nitric oxide to give the nitrosyl. The chloro and aqua species exist in equilibria in water

Septic shock is being studied in a number of (1 9) and complexes containing nitric oxide have laboratories and the arginine analogue inhibitors been known for well over a hundred years; of NOS have been studied clinically against this Kz[Ru(NO)C15],for instance, was isolated in disease (17). However, they have a number of the mid-nineteenth century. Ruthenium read- side effects, mainly affecting the local blood cir- ily forms nitrosyls and there are more known culation within organs, particularly the lungs nitrosyl complexes of ruthenium than of any (18). This is because in addition to inhibiting other metal (7). The Ru-NO bond is generally the formation of the undesirable excess quan- very stable and as a ligand nitric oxide is not tities of nitric oxide produced by i-NOS, they easily displaced, persisting through a variety also inhibit the production of nitric oxide by of substitution and redox reactions. c-NOS of endothelial cells. Many commercial Ruthenium @I) (d5)will react with nitric oxide and academic laboratories have attempted to to form six co-ordinate mononitrosyl complexes produce selective inhibitors of i-NOS but to- with a linear Ru-N-0 group. The Ru(II1) is date there has been little success reported. reduced to Ru(I1) with the ligand being formally However, in the Biomedical Technology Group NO' (as mentioned earlier this is an oversim- at Johnson Matthey we have pursued a differ- plification and ignores the structural problems ent approach to the problem by exploiting our associated with nitrosyl chemistry). Therefore knowledge and expertise in co-ordination chem- ruthenium appeared to be a good candidate as istry and inorganic pharmaceuticals. Armed the basis of a nitric oxide scavenger. with the knowledge that nitric oxide can act as a ligand for transition metals, we have exam- Drug Design ined metal complexes as possible scavengers for When designing drugs a number of factors the therapy of nitric oxide-mediated disease. have to be taken into consideration (20). These Ruthenium has a rich co-ordination chemistry include the necessity that the chosen compounds

Platinum Metals Rev., 1995, 39, (4) 156 must be of low toxicity and that the distribution pressure was measured and taken to indicate of the drug within the body and its excretion that nitric oxide had been removed. At the end from the body must be controllable (pharma- of the experiment the reaction mixture was freeze cokinetics). Toxicity and pharmacokinetics are dried and analysed by infrared spectroscopy. interrelated and both depend upon the chemi- A peak at 1897/cm, which is characteristic of cal properties of the compound, such as its sol- the linear Ru-N-0 bond, was indicative that ubility and its chemical reactivity. nitric oxide had been bound and that the ruthe- The chemical properties of the transition met- nium(I1) nitrosyl compound had been formed. als are well suited to deal with the problems of The proposed mechanism for this reaction drug design: transition metals have variable oxi- involves the formation of the aqua species dation states, ligands are co-ordinated in a pre- [Ru(Hedta) (H20)],JM6245, which takes place cise spatial arrangement and can be chemically readily at physiological pH (22), see Figure 4. modified so enabling the properties of the com- This is followed by associative ligand substitu- plex to be fine-tuned to control the pharma- tion with nitric oxide to give the nitrosyl. The cological interactions in a biological system. For pendant carboxylate group may facilitate this a nitric oxide scavenger we require a ligand set substitution (23), since if the carboxylate is which is itself stable but which promotes spe- replaced by an alcohol group there is a reduc- cific binding of nitric oxide. Generally ligands tion in the activity which is observed during the around ruthenium0 are kinetically inert and biological tests (see below). there is another benefit in that the formation of Kinetic studies performed at the University of the Ru-NO bond further stabilises the trans lig- Essex, using stopped-flow equipment, indi- and in the resulting ruthenium(II) complex. cate that the rate of formation of the nitrosyl is so fast that the reaction takes place within the Ruthenium(III)polyaminocarboxylates dead time of the instrument ( > 2 ms) at room One class of ligand that satisfies most of these temperature. Measurements made at 6.5"C give requirements is the polyaminocarboxylates (2 1). a rate constant of 2.6 x 107/Ms. The parent compound K[Ru(Hedta)Cl] (JM1226) has emerged as the potential front JM1226Pharmacological Activity runner in the search for a metal-based nitric The next step was to investigate the ruthenium oxide scavenger, see Figure 4. The ligand, compound in a simple biological system. We ethylenediaminetetraacetic acid (edta), is exploited the fact that macrophage cells pro- pentadentate leaving one co-ordination position duce nitric oxide in response to the bacterial cell available for substitution by nitric oxide. The wall component, lipopolysaccharide, and to complex is water soluble and should therefore interferon-y. We used a macrophage cell des- remain in the blood and not cross lipophilic cell ignated RAW264 which can be cultured in the membranes. laboratory (24). The nitrite in the culture This has two important consequences: it medium was assayed as a measure of the amount should have a good pharmacokinetic profile, of nitric oxide produced by the cells. It was found such as: be rapidly excreted in the urine, only that the level of nitric oxide could be reduced have access to the excess nitric oxide in the by the i-NOS enzyme inhibitor LNMMA (the bloodstream, and not be available to the nitric control experiment) and also by JM1226, see oxide produced by endothelial cells responsible Figure 5 (a). for regulating blood pressure. In order to confirm the binding properties of Initial evidence for the nitric oxide binding JM1226 for nitric oxide in our biological sys- ability of this compound was provided by a tem, we also made use of the ability of chemical study in which nitric oxide gas was macrophages to kill tumour cells. We demon- introduced above a stirred solution of the test strated that RAW264 cells could kill the mouse compound in a closed apparatus. A decrease in tumour cell P8 15 and that this was mediated by

&tinurn Me& Rm., 1995,39, (4) 157 also able to protect the P815 cells against RAW264 nitric oxide-mediated cell killing, see Figure 5(b). Similar results were obtained with the aqua species [Ru(Hedta)(H20)]. Having demonstrated that we had a potential nitric oxide scavenger we then needed to get closer to the real life situation. Collaborators were using isolated rat tail arteries to investigate the vasodilatory properties of nitric oxide donors (25). One commonly used nitric oxide donor is -LPSlIFN +LPS/IFN LPSllFN LPSllFN the nitrosothiol S-nitroso-N-acetylpenicillamine +JM1226 +NMMA Fig. 5 The RAW2a macrophage cell lieused (SNAP). This compound will break down in as a biological system for testing the ability water to release nitric oxide. The addition of of ruthenium(II1) compounds to scavenge SNAP to an isolated artery preparation was nitric oxide. RAW264 cells produce nitric oxide when activated with lipopolysaccharide and found to cause it to relax or vasodilate in a dose- interferon-y (+LPSILFN). dependent manner with an ED50 (the con- (a) JM1226, K[Ru(Hedta)CI], at a concen- centration giving a 50 per cent relaxation) of tration of 100 pM can reduce the level of mea- surable nitrite, produced by oxidation of nitric 6.0 pM. Haemoglobin, which forms an iron- oxide in the cell culture medium, showing the nitric oxide complex, will attenuate this response. potential to scavenge nitric oxide in a biolog- When JM6245, the aqua derivative of JM1226, ical environment. Background levels were determined in the absence of activators was tested at a concentration of 10- M in the (-LPSILFN). The nitric oxide synthase inhib- isolated artery model the SNAP response was itor, L-NMMA, a positive control at a concen- attenuated, giving an ED50 of 1.8 mM, which tration of 250 pM, also reduced nitrite levels. Error bars represent a standard error of mean is a 300-fold inhibition in the response of the n=3 artery. Using the isolated artery model, it has also been shown that JM6245 will reverse the I -r poor response of the artery to vasoconstrictor drugs, which is a major clinical problem when trying to treat patients with septic shock. We have gone further with this work, demonstrating that JM1226 has a positive benefit in two models of nitric oxide-mediated septic shock (26). In these models of disease the activity displayed by JM1226 is indicative of the poten-

-LPS/IFN +LPS/IFN LPS/IFN LPSllFN tial therapeutic efficacy of the ruthenium(II1) +JM1226 + NMMA polyaminocarboxylates. (b) JM1226, K[Ru(Hedta)CI], can protect against nitric oxide-mediated cell killing. The nitric oxide generator cell was coeultured with Conclusion the P815 tumour cell. Activated RAW264 cells The use of inorganic nitric oxide scavengers killed 50 per cent of the P815 cells. Viability in is a novel approach to the therapy of diseases the presence of 100 pM JM1226 was raised to 75 per cent. Error bars represent a standard mediated by excess production of nitric oxide. error of mean n = 6 We have discovered a class of compounds, the ruthenium(II1) polyaminocarboxylate complexes, which have pharmacological activity in nitric oxide. The removal of nitric oxide should biological systems ranging from cultured cells have a protective effect, and in the control exper- through to sophisticated disease models. The iment the enzyme inhibitor L-NMMA inhib- project has progressed rapidly through the early ited cell killing. More importantly JMl226 was stages of pre-clinical research and development

PlatinumMeraLF Rev., 1995, 39, (4) 158 since our patent was filed in 1993 (21). There ated diseases. Indeed inorganic medicinal chem- are many obstacles still to be overcome on the istry may provide the key to success in this field road to clinical success but the indications are of study, where the traditional organic chem- positive. istry approach to drug design appears to be Preliminary studies suggest that these com- struggling; and future prospects appear very pounds possess low toxicity and many of the encouraging for this potential new addition to desired pharmacokinetic properties. There is the inorganic pharmacopoeia. plenty of scope for Iigand modification and an Acknowledgements extensive synthetic programme is enabling new The success of a major project is the result of team- compounds with the potential for better activ- work. My fellow members of the project team are Drs. Elizabeth Slade, Barry Murrer and Nigel Powell at ity to be identified. the Johnson Matthey Technology Centre and Dr. Jean Minor chemical modifications are also known Vollano at Johnson Matthey Biomedical Research, to affect activity, thus giving scope for the design U.S.A. Thanks are due to Dr. F. W. Flitney, University of St. Andrews, Professor M. T. Wilson, University of further ruthenium compounds which might of Essex, and Professor F. Y. Liew, University of be used in the many diverse nitric oxide-medi- Glasgow, and to their colleagues. References 1 S. Moncada, R. M. J. Palmer and E. A. Higgs, 15 A. Tsai, FEBSLett., 1994,341, 141 Pharmacol. Rev., 1991, 43, 109 16 D. A. Wink, J. F. Darbyshire, R. W. Nims, J. E. 2 C. Nathan, FASEBJ., 1993,6,3051 Saavedra and P. C. Ford, Chem. Res. Toxicol., 1993, 3 C. F. J. Barnard, Platinum Metals Rev., 1989, 33, 6, 23 (4.1, 162 17 A. Petros, D. Bennet and P. Vallance, Lancet, 1991, 4 M. J. Abrams and B. A. Murrer, Science, 1993, 338, 1557 261,725 18 F. M. Robertson, P. J. Offner, D. P. Ciceri, W. 5 F. A. Cotton and G. Wilkinson, in “Advanced K. Becker and B. A. PrUitt, Arch Surg., 1994,129, Inorganic Chemistry”,John Wiley and Sons, Inc., 149 New York, 1980, pp. 423425 19 E. A. Seddon and K. R. Seddon, “The Chemistry 6 Y. Henry, M. Lepoivre, J.-C. Drapier, C. Ducrocq, of Ruthenium”, Elsevier, Amsterdam, 1984 J.-L. Bowher and A. GuiSSani, FASEB3., 1993, 20 C. F. J. Barnard, S. P. Fricker and 0. J. Vaughan, 7, 1124 in “Insights into Speciality Inorganic Chemicals”, 7 F. Bottomley, Coord. Chem. Rev., 1978, 26, 7 ed. D.T. Thompson, Royal Society of Chemistry, 8 J. A. McCleverty, Chem. Rev., 1979, 79, 53 Cambridge, 1995, pp. 35-61 9 R. F. Furchgott and J. V. Zawadzki, Nature, 1980, 21 M. J. AbramS, s. p. Fricker, B. A. Murrer and 288,373 0. J. Vaughan, WorldPatentAppl.95/5814A, 1995 10 R. M. J. Palmer, A. G. Ferrige and S. Moncada, 22 T. Matsubam and c. CrkwG Inor&?.Chem., 197% Nature, 1987, 327, 524 18, 1956 1 1 L. J. Ignmo, G. M. Buga, K. S. Wood, R. E. Byms 23 A. A. Dimantis and J. v. Dubrawsb Inog Chem., and G. Chaudhuri, Proc. Natl. Acad. Sci. USA., 1981,20, 1142 1987,84,9265 24 S. P. Fricker, E. Slade and N. A. Powell, Biochem. 12 J. B. Hibbs, in “Iron in Central Nervous System Soc. Trans., 1995, 23, 231s Disorders. Key Topics in Brain Research”, eds. 25 F. w. Flitney, 1. L. Megson, D. E. Flitney and Reiderer and M. B. H. YOU*, Springer Verlag, A. R. Butler, Br. J. Pharmacol., 1992, 107,842 Vienna, 1993, pp. 155 26 F. Q. Cunha, J. Assreuy, D. W. Moss, D. Rees, L. 13 B. S. S. Masters, Ann. Rev. Nur., 1994, 14, 131 M. c. Leal, S. Moncada, M. Carrier, C. A. 14 R. G. Knowles and S. Moncada, BWchem. 3., 1994, O’Donnell and F. Y. Liew, Immunohgy, 1994,81, 298,249 21 1 Platinum and Palladium Convert Biofuel By-product The search for non-polluting automotive fuels 165-1 76) report that they can orientate the selec- has encouraged a growth in alternative fuels, tivity of glycerol oxidation to oxidation of the pri- including biofuels such as ethanol and biodiesel. mary or secondary alcohol function. A 77 per Several countries already use biofuels and in cent selectivity at 90 per cent conversion to glyc- Europe biodiesel is produced &om rapeseed oils, eric acid on palladium catalysts, and a 55 per cent yielding up to 14 per cent of potentially valuable selectivity to glyceric acid on platinum catalyst glycerol. Now, R. Garcia, M, Besson and P. were achieved. A bismuth-platinum catalyst Gallezot (AppZ. Cutal. A: Gm., 1995,127, (1-2), achieved a 37 per cent yield in dihydroxyacetone.

Platinum Metals Rev., 1995, 39, (4) 159 Fourth Grove Fuel Cell Symposium FROM TECHNICAL SUCCESS TO THE CHALLENGES FACING COMMERCIALISATION “Opportunities, Progress and Challenges” was The PEMFC can operate at higher power den- the theme chosen for the Fourth Grove Fuel sities than other fuel cell types and, because of Cell Symposium, held at the Commonwealth this and its intrinsic simplicity, it is considered Institute, London, &om 19th to 22nd September suitable for both stationary and transportation 1995. Some 250 delegates from 23 countries applications. Progress by Ballard Power Systems heard that fuel cells, used for clean and efficient of Canada, in the development of a commercial power generation, had made tremendous tech- product for both applications, was described by nical progress over the two years since the last K. B. Prater. A prototype stationary 250 kW Grove conference. Most advances had been power plant, operating on natural gas and pro- made with the phosphoric acid fuel cell (PAFC) ducing grid quality AC power, is due for com- and the proton exchange membrane fuel cell pletion in early 1996, with a demonstration of (PEMFC), both of which operate at low tem- pre-commercial units in a utility environment peratures and employ platinum-catalysed elec- being on schedule for field trials in 1997 to 1999. trode materials. A more tangible indication of the potential The growing acceptance that fuel cell tech- of this fuel cell was demonstrated by its appli- nology is now proving itself in use was demon- cation in powering transit buses. Following the strated by the considerable attention paid at this first phase feasibility demonstration in 1993, conference to cost reduction, market entry Ballard have now produced the pre-commer- opportunities and the issues surroundingfuelliig cia1 prototype of a fuel cell powered zero emis- and infrastructure. sion transit bus. In this full sized 40 ft commercial bus, a PEMFC engine comprising Fuel Cell Technology Status twenty Ballard second generation stacks, pro- The PAFC is the fuel cell closest to widespread duces a total of 200 kW (275 hp) - the same commercial exploitation. The leading world power as the diesel engine normally installed in developer is ONSI, a joint venture between the bus. International Fuel Cells (IFC) and Toshiba. Further evidence of the commercial viability Their fleet of fifty-six PC25A 200 kW co-gen- of this application is the fact that the fuel cell eration power plants have been successfidly oper- engine occupies the same space as the diesel ated by their owners over the past three years. engine, see Figure 1, and provides at least the H. D. Ramm of IFC reported that the PC25A same performance. The fuel cell supplies the units have now accumulated 750,000 fleet hours entire motive power for the bus, and also the of operation, with a remarkable worldwide aver- power for lighting and air conditioning. The age availability of 94 per cent and a mean time buses are powered by hydrogen stored in com- interval between power plant down time of 2,200 pressed gas cylinders in the roof space, and have hours. This unprecedented reliability is already a range of 400 km (250 miles). Refuelling with significantly better than the conventionalmature hydrogen at the bus depot is expected to take co-generation technology. only minutes and is seen as a workable fuelling The next generation PC25C system is one option for fleet vehicles. third smaller and lighter than the PC25A, and These second generation stacks produce 13 costs half as much to manufacture. The plant kW under standard operating conditions at an is available at $3,00O/kW and ONSI already has average cell voltage of 0.58 V. The power buyers for two-thirds of the 50 plants it intends density output of 300 W/1 is double that of the to build over the next two years. original 5 kW stacks employed in the first bus.

Platinum Met& Rev., 1995,39, (4), 160-164 160 Fig. 1 The prototype Ballard commercial zero emiaaion transit bun L powered entirely by a compact 200 kW PEMFC engine which occupies the same apace. and vohune as the comntiod diesel engine powered versions. The fuel eel1 provides all the power, heating and lighting required by the lnu

Ballard also reported that the third phase in This stack exceeds the power density targets the commercialisation of the transit bus involves identified in the U.S. programme -“Partnership fleet mals by transit companies in routine oper- for a New Generation Vehicle” (PNGV) . Recent ation. The first of these, to start in 1996, has progress has been so successful, that even for recently been announced by the Chicago Transit this application, the emphasis will shift away Authority. The scheduled date for full bus com- from the achievement of key performance cri- mercialisation, powered by a third generation teria, towards maintaining this performance in stack, currently under development, is 1998. stacks manufactured in high volumes at costs These buses will be designed to have a range comparable to those of the present day internal of 560 km (350 miles). combustion engines. Progress was also reported between Ballard and Daimler-Benz on the development of stacks Opthising Platinum Use with very high power density for use in small An example of the progress being made in cost passenger vehicles. The target power density for reduction is shown by the requirement of the this, the most demanding application, is usu- platinum electrocatalyst. The early generation ally regarded as 800 to 1000 WA. Ballard used PEMFC stacks use high platin& loadings of this conference to announce that they had pro- around 4.0 mg/cm2 of electrode area. This is duced a stack with a volume of 31.9 litres deliv- economically unfeasible for most applications. ering a continuous output of 32.3 kW at a high The PNGV programme is aiming to achieve average cell voftage (thus high efficiency) of loadings of 0.1 mgkm’ by the year 2004, and 0.68 V. The stack operates at lower-than-stan- although loadings of less than 0.5 mglcm’ have dard operating pressures to increase efficiency frequently been demonstrated in small labora- further, and easily meets the 1000 WI1 target. tory fuel cells, this now needs to be confirmed

Plarinum Metaii Rm., 1995, 39, (4) 161 on full scale stacks. Ballard believe that total cell the fuel cell stack (DMFC). Current work on platinum loadings of less than 1.O mg/cm2are this technology was described by M. Waidhas, attainable and they are working to achieve this W. Drenckhahn, K. Mund and W. Preidel of with mass production techniques in their pro- Siemens. They reported considerably improved gramme with Johnson Matthey. levels of cell performance when a polymer mem- The low operating temperature fuel cells (< brane, similar to that used in the hydrogen 200°C) of the PAFC and PEMFC types, con- fuelled PEMFC, was employed as the electrolyte tinue to use exclusively platinum or promoted (SPE-DMFC). Previous cell current densities platinum based electrocatalysts for both elec- of 50 dcm' at 0.4 V have been too low to be trode reactions. The technical poster session of practical use, due to poor kinetics of the highlighted some of the current research into methanol electro-oxidation reaction, but new electrocatalyticmaterials. Many researchers Siemens have now been able to achieve current are modifying platinum so it is able to tole,rate densities of up to 400 mA/cm2 at 0.5 V and trace levels of carbon monoxide, present in Faradaic efficiencies of over 90 per cent. Better reformed hydrogen, for PEMFC applications. kinetics at the platinum based catalysdmem- Promising initial results using tungsten oxide brane interface may contribute to this improve- promoted platinum/ruthenium alloys were ment, although the best results have been described by A. C. C. Tseung, K. Y.Chen and obtained at 140°C using pure oxygen, which P. K. Shen of Essex University. is impractical for most high volume applications. In the United States the Jet Propulsion Fuelling Fuel Cell Powered Vehicles Laboratory is at the forefront of renewed inter- It is presently anticipated that small vehicles, est in DMFCs, and in a poster presentation (H. unlike buses, will have to be fuelled with a high Frank, S. R Narayanan, W. Chm, B. Nakamura, energy density liquid fuel, since it is unlikely T. Valdez, S. Surampudi and G. Halpert) on that hydrogen storage technology will advance the SPE-DMFC programme, reported that plat- sufficiently for them to be able to store on-board indruthenium remained the electrocatalyst adequate quantities to give acceptable vehicle of choice for methanol electro-oxidation, and ranges. To-date the favoured option has been that performances on air operation of up to 300 to reform liquid methanol on-board the vehicle dcm2at 0.4 V were being achieved. in order to produce a hydrogen-rich fuel for the Although these performances are creating fuel cell stack. greater interest, there is still need for further This approach has been adopted by Daimler- improvement, through advances in the cataly- Benz in their fuel cell vehicle programme, as sis of both the methanol oxidation and oxygen reported by T. Klaiber, and also by General (air) reduction reactions. Motors in their U.S. Department of Energy/ PNGV programme. Although steam reforming DieseUGasoline Fuel is the most highly developed process, there is The growing maturity of fuel cell stack tech- growing interest in partial oxidation reforming, nology was demonstrated by discussion of the which, because it is an exothermic reaction, can key issue of fuel infrastructure, particularly for achieve a more rapid start up and response under mobile applications. C. Borroni-Bird of Chrysler dynamic conditions. The intrinsic simplicity of strongly advanced the view that the preferred the latter approach and potential lower cost is choice of fuel should not be methanol but exist- viewed as the most important factor at this stage ing fuels such as gasoline/diesel. This is due to in the commercialisation of fuel cell powered a belief that existing oil pipelines cannot be used vehicles. for distributing methanol, due to its highly The most elegant solution to the technical corrosive nature. challenge of on-board reformer development is Additional factors, such as the high cost of the direct use of liquid methanol oxidation in investing in new methanol plant, the cost of

Flatinurn Metah Rev., 1995,39, (4) 162 methanol and its lower energy density were cited planar 10 kW type as a mobile electric power by others supporting this stance. It was sug- generating system was described by L. J. Frost, gested that the very low efficiency of reform- R. M. PriVette and A. C. Khandkar of SOFCo. ing petroleum based fuels, for example diesel fuel, ifused in a partial oxidation reactor, would Market Opportunities be offset by the much higher efficiency of diesel Reducing cost was the key topic for discussion production, relative to that of methanol. and in particular how to reduce production costs The U.S. Department of Energy (DOE)is sup- to enter the market; however, in order to achieve porting a programme being undertaken by the necessary lower costs, volume manufac- Arthur D. Little, that has a target of a 50 kW turing resulting from market penetration is first gasoline fuelled partial oxidation reformer by needed! 1997. Laboratory results have shown that gaso- Many speakers, including H. D. Ramm of IFC, line can be successfully reformed to a hydrogen emphasised the targeting of high value niche containing fuel. applications;such as reliable power for hos- pitals, high quality power for computer, telecom- High Temperature Fuel Cells munications and data centres, and as alterna- The most advanced high temperature fuel cell tives to centralised power generation where is the ERC (Energy Research Corporation) transmission, distribution and the provision of 2 MW molten carbonate fuel cell (MCFC) new lines is a contentious issue. The entry mar- demonstration at Santa Clara, California. This ket has to be specialised and clearly focused system, which was described by D. R. Glenn of on applications where the benefits offered by Fuel Cell Engineering Corporation, is due for fuel cells can be fully valued. completion and start up in early 1996. The Indeed, for stationary applications the real cost higher intrinsic efficiency of this fuel cell (design of fuel cell power generation should be assessed target is > 52 per cent) gives it the potential to against the complete life-cycle costs, which compete with existing generating technologies should include capital cost, installation, oper- in the multi-megawatt power generation range. ation costs (maintenance and fuel) and over- A further key advantage is its fuel versatility, haul. Ramm reported that the PC25C were now since it can operate on, for example, natural gas, approaching a figure of 1.5 centskwh over a 20 landfill gas, biogas or fuel obtained from coal year life cycle. gasification. The cost issue was taken a step further by P. Stacks of the type to be used in the plant have Bos of Polydyne, who suggested that minimis- successfully accumulated 100,000 hours of oper- ing the financial risk was critical to fuel cell com- ation in controlled environments, and ERC are mercialisation. The cost of commercialising a confident of their performance capability. A 2 MW utility system was estimated to be 200 market entry for a 2.8 MW power plant is tar- times larger than that of a 2 kW system. As fuel geted for 1999. cell use in transport is unlikely to provide an early The success of both this and the other signif- commercial market, due to the low market value icant MCFC demonstration - M-C Power’s two caused by the low cost of the internal combus- 250 kW power plants -will be critical to the tion engine, he identified the stand-alone micro- future of this fuel cell technology. co-generation residential application as a The even higher temperature operated (- high value entry market. A consortium of 12 1000°C) solid oxide fuel cell (SOFC) can be major utilities have formed the “Small Scale Fuel designed with either tubular or planar cell Cell Commercialisation Group” to demonstrate geometries. A 25 kW unit of the former type, is 50 to 100 2 kW units per utility, probably based being developed by Westinghouse and was on PEMFC technology, by 1998. reported to have now achieved over 7,000 hours The opportunity offered by the residential mar- of operation, whereas the development of a ket was identified by other groups, including

Platinum Metals Rev., 1995, 39, (4) 163 B. Barp, R. Diethelm, K. Honegger and E. now appears the more acceptable fuel process- Batawi of Sulzer Innotec, who are working on ing route despite the slightly lower system effi- developing the SOFC for this application. ciency projected by most model analyses. For transportation,heavy-duty vehicles such as transit buses or trucks represent the best Conclusions opportunity for early market entry. The U.S. The PAFC co-generation plants continue to DOEfigures show that in North America the demonstrate highly efficient and reliable oper- current annual demand is for 25,000 buses and ation, but large markets are needed before a fully 900,000 trucks (> 10 klbs). S. Chalk, of the U.S. cost effective product can become widely avail- DOE,reported that if the forthcoming zero emis- able. The PEMFC system has made rapid sion regulations were adopted by California and progress with the development of high power the North Eastern states, there would be a total density stacks which meet targets for trans- requirement of 353,000 zero emission vehi- portation applications. Early market opportu- cles (ZEVs) in the year 2003. nities lie with fleet vehicles, such as transit buses, In the near term these will be geared to bat- which can tolerate larger sizes, higher costs, and tery cars, and the DOEpredict that fuel cell cars on-board hydrogen fuel storage and depot refu- will not enter the market until 2007, and will elling. Commercialisation is on schedule for the attain 8 to 10 per cent of new annual sales by end of the decade. Opportunities for light-duty 2030 (currently 16 million new vehicles per year passenger cars have been provided in the United in North America). The DOEmodel makes the States by the zero emission regulations, to be assumption that fuel cells and all other enacted in 1998, and the programme to improve competing new technologies would be equally vehicle fuel economy. successful in meeting technical and economic The technical progress over the past three years goals. is such that attention is moving away from fuel Since cost was viewed by several speakers as cell stack technology to issues of cost, market the most critical factor influencing the rate of entry opportunities and the fuelling Mastruc- commercialisation, they believed that stack devel- ture. These are the key challenges for the lat- opers should not put undue emphasis on fac- ter half of the 199Os, in the development of a tors such as stack efficiency at this stage. For commercial market for power generation based example, the much simpler partial oxidation on fuel cell technology. G.A.H.

Osmium, the Densest Metal Known Until recently much confusion existed in the with newly accepted atomic weights of 190.23 literature as to which is the densest metal, 2 0.03 for osmium and 192.217 f 0.003 for osmium or iridium. Crabtree reviewed the exper- iridium the contribution to the uncertainties of imental data, but his calculated densities of 22.59 the densities is now minor (3). f 0.02 g/cm3 and 22.57 k 0.02 g/cm’, respec- Using the lattice parameters selected previ- tively, led to an overlap in the uncertainties and ously by the present author (2), the calculated a suggestion that the problem had not been solved density of osmium is revised to 22.587 f 0.009 (1). However, in a similar review by the pre- g/cm’ while that for iridium remains the same. sent author, calculated densities at 20°C of On these grounds it is suggested that osmium 22.588 ? 0.015 g/cm3and 22.562 f 0.009 g/cm’, can now unambiguously be considered to be respectively, suggested that the problem just may the densest metal at 20°C. J.W.A. have been resolved in favour of osmium (2). Although the uncertainties calculated for the References densities are usually dominated by the accura- 1 R. H. Crabtree, J. Less-Common Met., 1979, 64, cies assigned to the lattice parameters, the accu- (113 7 2 J. W. Arblaster, Platinum Metals Rev., 1989, 33, racy of the atomic weight can also contribute (I), 14 significantly - if it is poorly known, as was the 3 Commission on Atomic Weights and Isotopic case for osmium until quite recently. However Abundances, Pure &Appl. Chem., 1994,66,2423

Platinum Metals Rev., 1995, 39, (4) 164 New Materials for Fuel Cell SvstemsJ A REPORT OF THE FIRST INTERNATIONAL SYMPOSIUM

The first of an intended biennial symposium, of the membrane itself - presently costing some The First International Symposium on New $700/mz, is a considerable drawback. At pre- Materials for Fuel Cell Systems, was held at the sent, the membrane component of a PEMFC Montreal Bonaventure Hilton, Canada, from fuel cell stack accounts for 20 to 30 per cent 9th to 13th July 1995. The symposium, which of the total cost of the materials. Accordingly, was organised by the Labratoire d’klecrrochimie there is a considerable incentive to develop other et de Materiaw Energktiques, Ecole Polytech- membrane materials which can be prepared nique de Montreal, concentrates on the mate- by simpler and less expensive chemistry than rial science of fuel cell systems, rather than on the currently used perfluorinated sulphonic acid applications. As such, all aspects of the fuel cell polymers. system, namely catalyst, electrolyte and fuel pro- This latter point was discussed further by A. cessing components were dealt with. The meet- E. Steck of Ballard Advanced Materials, Canada, ing attracted some 120 delegates, including a who described the development of ion exchange large number of participants from industry. membranes beginning with the early work done The keynote address was delivered by A. J. at General Electric in the 1950s, to the perflu- Appleby from Texas A & M University, who dis- orinated membrane materials presently used in cussed “New Materials for Fuel Cell Systems”. PEMFC, which are manufactured by Du Pont He stressed the importance of the electrolyte, (Nafion) and Dow. Although these materials since it determines the properties required for are noted for their stability and good perfor- the other materials in the system. In practice, mance, the current cost is prohibitively high. In only a limited choice of materials is available: order for PEMFCs to be commercially viable strong acids, strong aqueous alkalis, molten for the automotive market, the membrane cost alkali carbonates and solid oxides. will need to be reduced to between $50/m’ and Appleby pointed out that there are gaps in the $150/m2.Steck then went on to describe work operating temperature ranges of fuel cells due being done at Ballard on the development of a to a lack of suitable electrolytes; for example low-cost membrane. This third generation mem- there is a gap between the upper operating tem- brane, BAM3G, appears close to achieving the perature of phosphoric acid fuel cells (PAFCs): goals of performance, stability and cost, which 2 1O”C, and the lower operating temperature for are required for commercialisation of PEMFC. molten carbonate fuel cell (MCFC): 625OC; and similarly between the upper temperature Fuel Processing for the MCFC: 675”C, and the lower temper- As well as the fuel cell stack, the symposium ature for solid oxide fuel cells (SOFCs): 900°C. also dealt with aspects of fuel processing. The The temperature windows, in which fuel cells keynote speakers in this session were R. Kumar are operated, are set by their performance char- and S. Ahmed from the Argonne National acteristics at the lower temperature and by mate- Laboratory, U.S.A., who presented work on fuel rial characteristics (stability and resistance to processing for transportation fuel cell systems. corrosion) at the upper temperature. They discussed the various means of producing hydrogen from fossil fuels (primarily methane Electrolytes and methanol) and described the comparative The proton exchange membrane fuel cell merits of each, using calculations of overall sys- (PEMFC) operates at the much reduced tem- tem efficiency. It was concluded that while all peratures of 60 to 100°C and has excellent per- fuel processor designs are driven by some performance characteristics; however, the expense formance criteria, transportation applications

Platinum Merak Rev., 1995,39, (4), 165-166 165 using low temperature fuel cells, especially the platinum and platinum-ruthenium catalysts PEMFC, set the most demanding constraints. modestly enhanced the methanol oxidation activ- In this case the fuel processing is best served by ity. They also showed that the addition of partial oxidation systems as they appear sim- H4SiW12010to the electrolyte improved the pler, compact and more responsive. methanol oxidation performance of a supported platinum-ruthenium catalyst. It is likely that the Catalysts adsorption of tungstic acid from solution onto Carbon supported platinum, usually in com- the catalyst was responsible for the enhanced bination with one or more other metals for both performance. anode and cathode reactions, remain the mate- The chairman of the symposium, 0. Savadogo rials of choice for new electrocatalysts for low from the Ecole Polytechnique de Montreal, dis- temperature fuel cells. H. A. Gasteiger and cussed the potential promotion of supported P. N. Ross from the Lawrence Berkeley platinum catalysts, used for oxygen reduction, Laboratories, U.S.A., discussed the differences by H2WO4 in both PAFCs and PEMFCs. It was between platinum-ruthenium and platinum-tin found, especially with low platinum loaded cat- alloys for both methanol and carbon monoxide alysts, that the addition of H2W04gave enhanced oxidation, using results obtained with bulk metal oxygen reduction kinetics for PAFC conditions. samples. It was found that while ruthenium can The last session of the Symposium was devoted adsorb both carbon monoxide and water, tin to new catalysts. Of particular interest was the can only adsorb water. Thus in catalytic reac- presentation by N. Alonso-Vante from the Hahn- tions involving carbon monoxide, platinum- Meitner Institut, Berlin, who discussed novel tin displays superior activity. ruthenium-based materials for oxygen reduc- A complementarypiece of work was described tion in acid electrolytes; the semiconducting by J. Stumper, D. Olligs and U. Stimming from transition metal selenides of general formula, the Institut fiir Energieverfahrenstechnik, Jiilich, (Ru,.,Mo,), SeO, (0.02 < x > 0.04; 1 < y > 3; Germany, in which the optimum surface com- z= 2y). At present, their oxygen reduction activ- position of platinum and ruthenium in plat- ity is somewhat poorer than platinum, but unlike inum-ruthenium alloys for carbon monoxide platinum cathode catalysts they have the electro-oxidation was probed using in-situ advantage of being tolerant to the presence of infrared spectroscopy. Only one type of car- methanol. The operation of Direct Methanol bon monoxide species was found on platinum- Fuel Cells usually leads to methanol being trans- ruthenium surfaces, suggesting that atomic mix- ported to the cathode through the electrolyte, ing occurs between platinum and ruthenium at where cathode depolarisation takes place. A the surface. methanol tolerant cathode catalyst would be a The use of platinum-ruthenium catalysts in significant technological breakthrough. This the form of supported materials was discussed was examined further during the poster session further by M. P. Hogarth, P. A. Christensen and with Newcastle University describing work on A. Hamnett from Newcastle University, who the sulphur analogues of the selenium material. presented encouraging results, discussed else- In view of the importance of material science where in this journal on page 173, of a methanol to improvements in fuel cell technology, this vapour fuelled PEMFC single cell which symposium was a welcomed addition to fuel cell achieved a power density of 0.2 Wlcm’. and electrochemical related conferences. It is The addition of tungsten to supported plat- hoped that the planned 2nd Symposium will inum and platinum-ruthenium catalysts was the take place in 1997. Copies of the proceedings subject of several presentations. A. R. J. of this symposium are available in North America Kucernak, C. J. Barnett, G. T. Burnstein and from COOPOLY 1’Ecole Polytechnique de K. R. Williams, from Cambridge University, Montreal, and in Europe from Technique et showed that the electrodeposition of “WO,” onto Documentation-Lavoisier, Paris. D.A.L., D.T.

Platinum Metals Rev., 1995, 39, (4) 166 Microstructure and Properties of Some Dispersion StrengthenedPlatinum Alloys THE INFLUENCE OF YTTRIUM AND ZIRCONIUM ADDITIONS By Qiaoxin Zhang, Dongming Zhang and Shichong Jia Advanced Materials Institute, Wuhan University of' Technology, Wuhan, China and Wulin Shong Department of Materials Engineering, Huazhong University of Science and Technology, Wuhan, China

The effect of adding very small amounts ofyttrium and zirconium to platinum alloys has been investigated. The results indicate that a platinum alloy which contains bath elements has a higher recrystallisation temperature and superior mechanical properties than a platinum alloy containing only zirconium. In addition, the platinum alloy which contains both yttrium and zirconium has a stable structure in which regular second phases have been found both in the grains and on the grain boundaries.

Platinum has excellent properties when used nium, or of yttrium and zirconium, was less than at high temperatures in oxidative atmospheres, 0.7 weight per cent. although its industrial application is restricted The ingot sized platinum-zirconium and plat- by its relatively low strength. In order to improve inum-yttrium-zirconium alloys were cold forged its strength, rhodium was initially used as a and rolled into sheets suitable for microstruc- strengthening element at contents less than 20 rural examination and also drawn into wires for to 25 per cent (1). Since the 1970s, ZGS plat- mechanical testing. No annealing was done dur- inum (2) and ODS platinum have been devel- ing these forming processes. However, to facil- oped; these being strengthened by well dispersed itate rolling it may be better to include an anneal. additions of zirconium oxide, ZrO, and yttrium The alloys were then annealed at various tem- oxide, Y,O,, respectively. The ZGS platinum peratures and later etched in a mixture of hot and ODS platinum alloys have much improved hydrochloric and nitric acids for measurement properties, but their processing technologies of the grain diameters. have to some extent limited their possible applications. Microstructure and Stability For this reason, we have studied the effects that of the Materials two alloying elements, yttrium and zirconium, The properties of these materials are deter- have on the properties of platinum. The alloys mined by their microstructures. As shown in were made by the metallurgical method described Figure 1, which is typical of many metals, the below and the results were encouraging. hardness of the platinum, platinum-zirconium and platinum-yttrium-zirconium alloys varied Alloy Preparation and with the annealing temperature (annealing lasted Experimental Methods for 0.5 hours) and decreased rapidly over the A mixture of platinum with yttrium and zir- temperature range in which recrystallisation conium, having purities of 99.95,99.9 and 99.9 took place. per cent, respectively, were electron-beam melted The hardness and also the recrystallisation in vacuum. The total weight fraction of zirco- temperature of the platinum-yttrium-zirconium

Platinum Metals Rev., 1995, 39, (4), 167-171 167 Fig. 1 Hardness versus anneal- 190. ing temperature curves of platinum, platinum-zirconiumand platinum-yttrium-zirconium 150. alloys, from which it can be seen that the recrystallisation temperature of the latter is some 450°C 110. higher than that of pure x' platinum w z 70. 4 I

30-

200 400 600 800 1000 1200 TEMPERATURE, 'C

alloy have higher values than those of platinum- grain size in the platinum-zirconium has grown zirconium. The hardness, Hv, of the platinum- significantly, and the platinum-yttrium-zirco- yttrium-zirconium alloy annealed at over 1200°C nium alloy has begun to recrystallise, but its is 72, and its recrystallisation temperature is grain size is still relatively small, see Figure 2. approximately 450°C higher than that of pure When annealed at 1200°C for longer periods, platinum. the grain size of the platinum-zirconiumchanges Microscopical analysis indicates that after substantially while the platinum-yttrium-zirco- annealing at 800°C for 0.5 hours recrystallisa- nium grain size is little changed, as shown in tion of the platinum-zirconium alloy occurs, Figure 3. with a very small grain size but with the elon- Therefore, it can be deduced that alloying plat- gate structure resulting from rolling still visi- inum with both yttrium and zirconium gives ble in some areas; the platinum-ytuium-zirco- superior structural stability compared with alloy- nium alloy does not show any recrystallisation. ing platinum with zirconium alone. This is very After annealing at 1000°C for 0.5 hours, the important for materials employed at high

Fig. 2 Photomicrographs for platinum- zirconium and platinum-yttrium- zirconium after annealing at 1000°C for 0.5 hours. The grains of the latter are smaller: (a) platinum-zirconium (a) platinum-yttrium-zirconium Magnification of (a) and (b) x 450

Platinum Metals Rev., 1995, 39, (4) 168 in our platinum-zirconium alloy is zirconium oxide formed during processing. In addition to this zirconium oxide on the grain boundaries, the platinum-yttrium-zirconium alloy also has f some regular shaped particles of an yttrium and zirconium compound distributed within the 200- grain. In- f These particles, which are only tens of 6 a nanometres in size, have not yet been studied, (3 but are likely to improve creep resistance and 100. high temperature stability. This is to be the next step of our work. 50. Physical Properties of the Materials 04 The resistivities of platinum-yttrium-zirco- 12 5 10 25 1C nium and platinum-zirconium alloys are a little ANNEALING TIME, h higher than that of pure platinum, while their Fig. 3 After annealing at 1200°C the relation- elongations are slightly less. However, their hard- ship between grain size and annealing time nesses and strengths are greatly improved com- shows that the alloy containing yttrium and zirconium is superior to that containing only pared to platinum, especially the high temper- Zirconium, and in both the grain growth is less ature strength and the creep resistance of the than occurs in platinum. The same working platinum-yttrium-zirconium alloy, see the Table. procedure was used for all three. materials

temperature. Additionally, it is considered that platinum-yttrium-zirconium is more stable than platinum-zirconium; the initial tendency to change is apparent in platinum-zirconium, but not in platinum-yttrium-zirconium. The distribution of a second phase in platinum-zirconium and platinum-yttrium-zirconium alloys annealed at 1200°C is illustrated in Figure 4. The second phase in the platinum-zirconium, which exists mainly on the grain boundaries, was analysed using an Energy Analysing Electron Microscope and found to be a zirconium compound. The main compounds in the platinum-zirconium alloy system are PtZr, Pt,Zr and Pt,Zr, and these are formed when the platinum alloy contains more than 3 per cent zirconium (4). However, as the amount of zirconium in the platinum-zirconium alloy which we were investigating was less than 0.7 per cent, the com- Fig. 4 Distributions of the second phase in platinnm- pound was not likely to be any of these three zirconium and platinum-yttrium-zirconiumalloys after annealing at 1200°C: platinum-zirconium compounds. It may be rea- (a) platinum-zirconiumalloy x 60,000 sonable to deduce that the zirconium compound (b) platinum-yttrium-zirconiumalloy x 72,000

Platinum Metals Rev., 1995, 39, (4) 169 Properties of Platinum, Platinum-Zirconium,Platinum-Yttrium-Zirconium and Platinum-10 per cent Rhodium Alloys (3,5)

Pure Pt Pt-Zr Pury-zR pT-10%rH

Resistance at 2OOC. pcm 10.6 (3) 12.46 12.42 18.4 (3)

TCR*/ OC; mean I-IOO~C 0.0039 (3) 0.0017 0.001 1 0.0017 (3) Tensile strength, UTS, MPa (annealed) 124 (3) 278 283 330 (3) Elongation, per cent, (annealed) 40 (3) 36 35 35 (3) Hardness, Hv (annealed) 40 (3) 65 72 75 (3) UTS at 12OO0C, MPa 35.2 (5) 40.0 44.6 58.8 (5) Rupture time, at 12OO0C, 25 MPa. h 11.5 (5) 3 7.6 307 (5) (at 4.9 MPa) (at 4.9 MPa)

* TCR: Temoerature coefficient of resistance

The values for hardness given in the Table were earth yttrium dissolved in platinum increases measured on sheet; all the other values in the the alloy strength more than yttrium alone in Table were determined using wire samples. The the platinum-yttrium alloy. strength of the alloys increases with increases in the total volume fraction of yttrium and zirco- [b] Dispersion Strengthening nium, but the elongation decreases. The second phase in platinum-yttrium-zirco- The stress-rupture life for platinum-yttrium- nium, distributed on the grain boundaries and zirconium at 1200°C and 25 MPa is similar to also in the grains, improves the high tempera- that of platinum-10 per cent rhodium alloy at ture strength and the creep resistance. 1000°C. Further work on stress rupture and creep data is presently being undertaken. [c] Boundary Strengthening The following three factors are believed to Compared with zirconium, yttrium is more result in the properties of the platinum-yttrium- inclined to deposit on the grain boundary, caus- zirconium alloy being superior to those of plating impaired boundary diffusion and migration inum-zirconium. (7). Therefore, it is more effective for platinum to be alloyed with small amounts of zirconium [a] Solution Strengthening and the rare earth yttrium, than it is to be alloyed The difference in the atomic radii between plat- with the same amount of zirconium alone. inum (1.38A) and zirconium (1.579A) is less than that between plathum and yttrium (1.797A), Conclusions so the platinum-yttrium-zirconium lattice is The addition of very small amounts of yttrium more distorted than the platinum-zirconium lat- and zirconium to platinum makes the platinum tice, which results in increased hardness. alloy structure more stable and greatly improves The difference in electronegativity between the recrystallisation temperature. The second platinum (2.2) and zirconium (1.4) is less than phase distributed on the grain boundaries and that between platinum and yttrium (1.2), so the within the grains improves the high tempera- bond forces and the polarisation effect in plat- ture strength and creep resistance. inum-yttrium-zirconium are greater; this These additions of yttrium and zirconium improves the high temperature strength (6). This improve the properties of platinum at both room is a special effect that occurs in alloys contain- and elevated temperatures, and alloying with ing very small additions of alloying elements. the two elements is more effective than alloying The interaction between zirconium and rare only with zirconium.

Platinum Metals Rev., 1995, 39, (4) 170 References 1 A. S. Darling, G. L. Selman and A. A. Bourne, 4 Chunxiao He and Guangchen Ma, “Equilibrium Platinum Metals Rev., 1968, 12, (I), 7 Diagram for Precious Metal Alloys’’, Metallurgical Industry Press, Peking, China, 1983 2 G. L. Selman, J. G. Day and A. A. Bourne, 5 Y. Ning, PreciowMet. (China), 1984, 5, (2), 42 Platinum Metals Rev., 1974, 18, (2), 46 6 T. T Kou, Wenhui Shu and Shouyu Dai, Acta Sci. Nat. Univ. JtZinensis, 1962, (l), 177 3 G.L. Selman and A. A. Bourne, Platinum Metals 7 Kunyu Zhao and Dingxin Li, Precious Met. Rev., 1976, 20, (3), 86 (China), 1993, 14, (2), 9

Modelling Techniques for Catalyst Development Computer-Aided Design of Catalysts EDITED BY E. ROBERT BECKER AND CAM0 J. PEREIRA, Marcel Dekker Inc., New York, 1993, 640 pages, ISBN 0-8247-9003-0, U.S.tl95.00 This book is the 5 1st in an occasionally excel- Soled, compares cobalt and ruthenium catalysts lent series on the chemical industries, and while in the context of models which combine transit has its limitations it is nevertheless a valuable port processes and elementary kinetics, and con- addition to the collection. The series consists cludes that selectivity is dominated by the trans- of assembled chapters on a theme contributed port processes rather than by the nature of the by distinguished professionals. As such the vol- active sites. umes often lack coherence and stand or fall Chapters on modelling for automotive emis- on the excellence of the contributions and the sion control by S. H. Oh, and design of mono- timeliness of the theme. This book is certainly lithic catalysts for improved transient reactor timely as the use of computing methods in catal- performance by K. Zygourakis, use platinum ysis is growing rapidly. Computer aided design catalysts as the basis for a discussion of mod- can mean different things; here the editors define elling in car exhaust systems. Oh reviews his it as “the process of selecting catalyst proper- outstanding work and shows that even with many ties that ..... optimise the reactor performance”. simplifying assumptions useful predictions as The emphasis on choosing catalyst properties to catalyst loadings and performance may be means that there is very little on the design of obtained. The application of this approach to new catalysts in this book. Rather the chapters heated catalysts was discussed at the recent deal with the methods for the measurement and North American Catalysis Society meeting. The modelling of catalyst parameters and the appli- importance of 2-dimensional modelling for pmb- cation of these methods in various industrial lems such as flow maldistribution and other processes. Also missing is any attempt to dis- transient effects is dealt with at greater length cuss the modelling and economics of entire by Zygourakis. processes and plants; the emphasis is firmly Palladium features most extensively in a chap- on the performance of the reactor section. ter on catalytic membrane reactors by T. T. The early chapters deal with modelling meth- Tsotsis, R. G. Minet, A. M. Champagnie and ods, such as: selectivity patterns in methane par- P. K. T. Liu. This topic has a long history and tial oxidation; modelling complex mixtures in remains popular due to the inherent elegance catalytic cracking using carbon centre methods; of controlling reactant addition or product Monte Carlo simulations for complex hydro- removal by a selective membrane. However large treating mixtures; pore diffusion models; cata- scale applications await the development of lyst pellet impregnation profiles and catalyst membranes that are thin enough and robust wetting effects on multiphase reactions. Later enough for the demanding conditions of most chapters concentrate on particular applications, petrochemical processes. such as Fischer-Tropsch catalysts, automobile This book is a useful contribution to bridging catalysts including transient behaviour in mono- the gap between chemical engineers and chem- lith reactors; polymerisation catalysts; mem- ists in the field of catalyst and reactor design. brane reactors and petroleum refining. Platinum While individual chapters may disappoint spe- group metals feature here most directly, par- cialists on any given topic, together they pro- ticularly platinum, palladium and ruthenium. vide a valuable introduction to the area and can The chapter on the design of Fischer-Tropsch be read profitably by non specialists; the book catalysts by E. Iglesia, S. C. Reyes and S. L. will be of use in advanced education. J.C.F.

Platinum Metals Rev., 1995, 39, (4) 171 Routes to Useful Products and Processes Insights into Speciality Inorganic Chemicals EDITED BY D. T. THOMPSON, The Royal Society Of Chemistry, London, 1995, 505 pages, ISBN 0-85404-504-X, E39.50

The needs of graduates contemplating indus- The increasingly important topic of catalysts trial research are addressed in this important for stereospecific synthesis is examined by J. M. book covering the major industrial applications Brown. Here platinum group metals find par- of inorganic chemicals. Its eighteen chapters are ticular use in reductive processes. There is ref- written by authors with wide experience of their erence to rhodium catalysts used for the prepa- topics. About half the chapters feature the plat- ration of L-DOPA, and rhodium systems based inum group metals, giving a fair indication of on bis(phospho1ane) designed by Du Font. The their relevance to industry. versatility of ruthenium binap complexes in In the chapter on refining J. Hill describes the alkene double bond hydrogenations is shown in occurrence of the platinum group metals, their the syntheses of citronellol and vitamin E, and extraction, including chemical processes based in a potential route to isoquinoline alkaloids. on precipitatiodfiltration, and improved pro- These ruthenium catalysts can also hydrogenate cesses using solvent extraction and ion exchange. ketones with a high enantioselectivity; the There is a good critique of the drawbacks to the rhodium analogues have commercial potential classical processes, and it is emphasised that a in vitamin B5 synthesis. Osmium tetroxide is major disadvantage to all the processes is that mentioned for Sharpless dihydroxylations. rhodium is extracted last. Automobile catalysis, a major use for platinum A chapter on the medical applications of inor- and rhodium, is addressed by M. Bowker and ganic chemicals, by C. F. J. Barnard, S. P. Fricker R. W. Joyner. The development of three-way and 0. J. Vaughan describes platinum anti- catalytic converters, the principles of catalyst cancer drugs and the development of cisplatin operation and surface chemistry are described. and carboplatin. Structure activity studies and Future developments include enhanced dura- the mechanism of action of these drugs are con- bility, which can be provided by palladium only sidered, but there is still much to find about the catalysts. The inventiveness of industrial scien- molecular basis of their action. tists will be challenged by legislation imposed Heterogeneous catalysis is considered by to reduce carbon dioxide emissions; when the G. C. Bond in a chapter on inorganic materials zero emission legislation comes into force non- as catalysts for chemical processes. This subject carbonaceous fuels may be necessary. is extensive, but refers to the importance of Other applications which involve the platinum the platinum group metals only in hydrogena- group metals include the electronics industry, tion, dehydrogenation, dehydrocyclisation, where ruthenium dioxide and bismuth ruthen- hydrogenolysis and Fischer-Tropsch chemistry. ate are used as thick film resistors and where The use of homogeneous catalysts in large palladium is used as a leaching inhibitor of sil- scale industrial processes is described by A. ver from thick film conductors. Additionally, Parkin. He discusses three processes employing tris(bipyridy1)ruthenium catalysts are being used platinum group metal complexes: the carbony- in solar energy conversion. lation of methanol by rhodium iodide based cat- This volume thus provides a valuable overview alysts, the hydroformylation of alkenes by of the industrial applications of inorganic mate- rhodium carbonyl phosphine complexes and the rials. Each chapter has a useful list of specific Wacker process for alkene oxidation to acetalde- and general references and key journals, thus hyde using palladium where the catalyst is regen- providing the reader with an easy means to erated by a copper redox system. acquire further information. M.J.H.R.

Platinum Metals Rev., 1995, 39, (4), 172 172 Platinum Metals in Electrochemistry FURTHER WORK ON ELECI’ROCATALYSTS REPORTED The Electrochem ‘95 Conference, organised cell, and the development of new oxygen reduc- by the Society of Chemical Industry and the tion catalysts. The power output kom a vapour- Royal Society of Chemistry was held at the fed methanol single cell was reported to be around University of Wales, Bangor, fiom 10th to 14th 200 mW/cmz at 113°C with 2 bar air, 5 M September 1995. During the week, parallel mini- methanol and a catalyst loading of 2.5 mg Wcm’. symposia covered the topics of: structure and Methanol cross-over from the anode to the cath- reactivity at interfaces, electrochemical pro- ode remains a problem, and another restriction cessing, polymers and novel materials, fuel cells to cell performance may arise from proton con- and electrocatalysis, corrosion, solid state ion- duction limitations at the membrandcatalystinter- ics and batteries, semiconductor electrochem- face. Improved platinum and platindruthe- istry, electroanalytical chemistry and environ- nium catalysts supported on carbon for methanol mental electrochemistry. Of the approximately oxidation were obtained by deposition ibm aque- 260 delegates, less than 10 per cent were from ous sulphito complexes, using hydrogen per- industry, which must be a cause for concern. oxide as the reducing agent. In addition, the Not surprisingly then, developments in new Newcastle group are studying rutheniundmolyb- instrumentation dominated much of the pro- denum based metal chalcogenide catalysts, made ceedings, and the latest advances in techniques, by the reaction of the metal carbonyls in xylene; such as FTIR, EXAFS, STM and AFM, are they continue to show promise as novel oxygen certainly striking. However, one felt occasion- reduction catalysts with acid stability. ally that some simple “wet chemistry” would Another catalyst issue of practical importance, have given just as much, ifnot more, insight into the dependency of intrinsic activity on particle- the fundamental science in question. size for oxygen reduction, was described by R. J. Potter of Johnson Matthey during a pre- Technical Presentations sentation of technical issues in the hydrogen-air The group at Bath University lead by Professor solid polymer fuel cell system. Work on dimen- L. M. Peter has been studying various indus- sionally stable anode materials in which the ser- trially-relevant systems including (together with vice life of PdO/titanium electrodes for oxy- ICI) the kinetics of chlorine evolution on tita- gen evolution in alkali solutions was significantly nidruthenium anodes. In this instance, the improved by the addition of zinc, was discussed less familiar open-circuit potential decay method by B. J. Hwang from the National Taiwan was used to elucidate important parameters such Institute of Technology. as the Tafel slope and exchange current density. In another presentation from Newcastle Among the results that his group achieved were: University, by K. Scott and W. M. Taama, pal- the identification of an activity threshold effect ladium was again described as an effective anode dependent upon the ruthenium content (with catalyst, this time for the anodic oxidation of the number of active sites being dependent upon sulphur dioxide in sulphuric acid. how “hard” the electrode is driven) and the dis- A number of groups are working on the devel- covery that chlorine can evolve without charge opment of conducting polymers containing transfer occurring. redox active metal centres, which include ruthe- A team from Newcastle University lead by nium, osmium and platinum, where the main Professor A. Hamnett and P. A. Christensen pro- application is in sensor technology. duced results on a number of aspects of electre The next conference will be held at Bath Uni- catalysis in fuel cells, including modelling the per- versity, and one hopes that this time there will formance of a solid polymer direct methanol fuel be a greater presence from industry. R.J.P.

Platinum Me& Rev., 1995,39, (4), 173 173 Ruthenium Effect on the Transformation in Equiatomic Titanium-Nickel Alloy PHASE STABILISATION AND MARTENSITIC TRANSFORMATION By E. L. Semenova, N. Yu. Rusetskaya, I? M. Petyukh and V. Ye. Listovnichiy I. N. Frantsevich Institute for Problems of Materials Science, Kiev, Ukraine

Martensitic transformations in equiatomic titanium-nickel and titanium- nickel based alloys are of interest because they are associated with the shape memory effect. Equiatomic titanium-nickel, which possesses such superior mechanical properties as high strength, elevated ductility and corrosion resistance, is the most important of several shape memory alloys. Here, the character of the martensitic transformalion in equiatomic titanium-nickel alloy with some of the nickel replaced by ruthenium is discussed. Data are presented on the temperature of the transformation upon heating and cooling, the transformation sequence and the stabilisation of the high temperature phase in TiNi- TiRu alloys, using electrical resistance, thermal expansivity and differential thermal analysis between -300°C and liquid nitrogen temperatures. Alloys which contained 0.5 to 2 atomic per cent ruthenium were found to undergo a two stage transformation, while the high temperature phase in titanium-nickel- ruthenium, which has BZ-type crystal structure, was stabilised by the addition of 2 atomic per cent ruthenium.

For the past twenty-five years we have been been investigated and melting diagrams have working on interactions occurring in binary and been constructed. The effects of substituting ternary systems containing platinum group met- rhodium and iridium for nickel in the equiatomic als. Among the systems we have studied are those titanium-nickel compound and of nickel for of the binary alloys of zirconium and the plat- rhodium in equiatomic titanium-rhodium sys- inum group metals. We have constructed phase tems, together with shape memory effects, have diagrams for these systems and shape memory also been studied (3, 4). effects have been found for the equiatomic zir- We are now studying interactions in the tita- conium-rhodium compound, as well as for the nium-cobalt-rhodium and titanium-nickel- equiatomic titanium-rhodium compdund. Shape ruthenium systems, and as a continuation of restoration is assumed to occur at about 1000°C our work on the phase diagram of the latter sys- for zirconium-iridium (1 ,2). The crystal struc- tem and on the effects to the martensitic trans- tures for the high- and low-temperature modi- formation in equiatomic titanium-nickel com- fications to equiatomic zirconium-rhodium and pound caused by additions of the platinum zirconium-iridium compounds have been deter- group metals, we discuss here the effect caused mined for the first time (2). by ruthenium. Alloys of the titanium-nickel- Later work has dealt with the ternary system: ruthenium system lying along the section titanium-nickel-platinum group metal. The through equiatomic phases of the titanium-nickel interactions in the systems of titanium-nickel- and titanium-ruthenium binary systems were rhodium and titanium-nickel-iridium along the investigated. section with 50 atomic per cent titanium have Rhodium and iridium additions are known to

Platinum Metals Rev., 1995, 39, (4), 174-179 174 TiNi-TiRu Transformation Temperature Data

sOLID tRANSFORMATION cOMPOSITION atomic RUTHENIUM eLECTRICALRSISTANCE tHERMAL EXPNANSION atomic per cent Ms Mt A, At T, Ms Mt

0 76 78 109 0.5 37 - 49 22 17 - 43 71 9 2 22 32 8 -28 17 $ 2 73 -65 -43 20 -73 -113 - 68 5 - -25 $ - lower the martensitic transformation tempera- ruthenium alloys containing 0.5, 1, 2 and 5 ture of equiatomic titanium-nickel compound atomic per cent ruthenium along the TiNi-TiRu when 6 atomic per cent is added along the iso- section were prepared from melts of their com- pleth of 50 atomic per cent titanium; the B2 ponent parts in an arc furnace under an argon crystal structure phase being stabilised down to gas atmosphere. In order to ensure a complete room temperature (3,4). Taking other data into melt, the ingots were remelted four times. The consideration, it can be concluded that the high weight losses which occurred on melting temperature B2-phase stabilisation down to amounted to only 0.05 weight per cent, so the room temperature in TiNi-TiPt and TiNi-TiPd final compositions were considered to be iden- alloys does not occur (although a contrary inter- tical to the initial ones. Investigations were car- pretation has been given by others (5)). ried out on both as-cast and annealed speci- In all the systems mentioned above the trans- mens. formation in TiNi-based alloys with nickel par- Measurements of microhardness were carried tially substituted by rhodium, palladium or plat- out by a standard method at a load of 50 g. Other inum occurs in two stages: determinations of the temperature dependence of the electrical resistance and thermal expan- temperature B2-phase + intermediate R-phase High sivity were performed using custom designed (rhombohedra1 structure) low temperature equipment (6). A modified differential thermal monoclinic Bl9’-phase. analysis method was used to record the solid The latter phase is preserved down to liquid state transformations in the alloys, fkom liquid nitrogen temperatures. Such a two-stage tran- nitrogen temperatures up to room temperature. sition in TiNi-based alloys is also typical of systems containing other Group VIII metals, such Experimental Results as cobalt and iron (7-9). and Discussion The constitution of the TiNi-TiRu section Experimental Method of the titanium-nickel-ruthenium ternary sys- The purities of the ruthenium powder and the tem is important for the present work. It is nec- nickel fkom which the alloys were prepared were essary to know the state of the parent phase 99.95 and 99.99 per cent, respectively; iodised which then transforms upon cooling. During titanium was also used. In order to avoid sput- our investigations we found that the titanium- tering and losses during alloying, the ruthenium nickel equiatomic alloy formed a pseudo- powder was sintered in vacuum at 1200°C and binary continuous solid solution with the tita- then melted in an arc furnace. Titanium-nickel- nium-ruthenium equiatomic alloy, TiNi-TiRu.

Pkatinum Metak Rev., 1995, 39, (4) 175 with temperature for alloys containing 0.5, 1 and 2 atomic per cent ruthenium between room temperature and liquid nitrogen temperatures, are shown in Figures 1 and 2, and also in the Table. Transformations in the TiNi-TiRu system occur in two stages, in a similar way to the transformations in titanium-nickel based alloys con- Ms taining additives of iridium, rhodium and iron (1, 3, 4, 7). This can be clearly seen from the shapes of the electrical resistance curves for alloys containing 1 and 2 atomic per cent ruthenium. The sequence B2 -+ R -+ B19’ is the same as for the alloys mentioned above, see Figures 1(b) and 1(c). The stages are associated with rhombohedra1 (R) and monoclinic (B19’) lattice distortions. TRis the temperature at which the parent B2-phase starts to transform into the intermediate R-phase and at which the electrical resistance sharply increases. At M, the martensitic transformation from the R-phase starts, causing a decrease in the resistance. Mf is the temperature at which the martensitic transformation is complete. On heating the alloys from liquid nitrogen temperatures the reverse transitions take place. A, and Af are the temperatures at the start and finish of the B 19‘ -+ R transformation, respectively, for alloys containing 0.5 and 1, and 2 atomic per cent ruthenium. 60’ -100 -50 0 50 One of the characteristicsof the electrical resis- TEMPERATURE, ‘C tance/temperature curves is that they reveal a Fig. 1 Resistivity-temperature variations in: pronounced hysteresis for R H B19’ transfor- (a) Ti50Ni49.5Ru0.5 (b) Ti50Ni49Rul mation, while the R-phase transformation, (c) Ti50Ni48Ru2, and R -+ B2, does not. Thus the cooling and heat- (d) Ti50Ni45Ru5 alloys ing curves for alloys containing 1 and 2 atomic Changes which occur at various temperatures are as follows: per cent ruthenium almost coincide at tem- At TRthe B2-phase begins to transform to the peratures above Af, see Figures 1(b) and 1(c). R-phase The B2 + R transformation causes a decrease At I& the martensitic transformation starts At M, the martensitic transformationfinishes in the volume of the sample, that is, the alloy At & the B19’ transformation to R starts is observed to shrink, while the R -+ B19’ trans- At Af the B19’ transformation to R fdshes formation results in an increase in the volume of the sample, that is, thermal expansion occurs, see Figures 2(b) and 2(c). Data showing the dependence of the electri- The observed variations in electrical resistance cal resistance upon temperature for alloys which and thermal expansion with temperature show contain 0.5, 1, 2 and 5 atomic per cent ruthe- that the R + B19’ transformation appears to nium, and measurements of thermal expansion represent a first order transition. This correlates

Platinum Metals Rev., 1995, 39, (4) 176 well with the DTA data, which demonstrate the corresponding thermal effects on heating and cooling (the thermal curves in Figure 3 show only the effects caused by heating, because the data on cooling obtained in our experiments reveal the same transition temperature regard- less of composition). The B2 + R transformation is a reversible process, according to the electrical resistance data shown in Figure 1, and almost reversible, as shown by the thermal expansion data in Figure 2, and therefore can be considered as a transformation close to a second order transition. However the DTA data shown in Figure 3 illustrate that the B2 + R transformation is accompanied by thermal effects, as is the R + B 19' transformation. It is worth noting that the intermediate phase formed during the B2 + R transformation in titanium-nickel based alloys with added iron (as well as in titanium-palladium based alloys with added nickel) is divided into ranges of incommensurate and commensurate phases with different crystal structures (10,ll). The first range (incommensurate phase) corresponds to the second order transition and the next range (com- -100 -50 0 50 100 mensurate phase) corresponds to the first order TEMPERATURE, *C transition. This could explain the thermal effect Fig. 2 Variation of thermal expansion with which was observed in the B2 + R stage for the temperature for the alloys: (a) Ti50Ni49.5Ru0.5 TiNi-TiRu alloys. (b) Ti50Ni49Rul The solid state transformation in titanium- (c) Ti50Ni48Ru2 nickel-ruthenium alloy containing 5 atomic per

W 2 K W b

I- Fig. 3 Differential thermal 5 analysis data on the solid state 2 transformations on heating for the alloys: 75 (a) Ti50Ni49.5Ru0.5 (b) Ti50Ni49Rul and (e) Ti50Ni48Ru2 TEMPERATURE, 'C

Platinum Metak Rm., 1995, 39, (4) 177 of the phase having the B 19' crystal structure. The microhardness of the titanium-nickel- ruthenium alloys varies with composition and is at a minimum for an alloy containing about 82 2 atomic per cent ruthenium, and at a maximum for an alloy containing about 1 atomic per cent ruthenium, see Figure 5. A comparison of these findings with those obtained from the electrical resistance and thermal expansion analyses indicates that the minimum is in accor- dance with the absence of a martensitic transformation in the alloys, and that the maximum -1 50 4 I is associated with accumulation of the R-phase. 0 2 4 6 8 10 TiNi RUTHENIUM ADDITION, at:/. Comparison of the results of the present investigation with data hmthe literam on the influ- Fig. 4 Phase structure transformationswith temperature in Tdi-TiRu alloys for ruthenium ence of platinum metals on the martensitic trans- additions from 0 to about 8 per cent formation in titanium-nickelbased alloys enables the following observations to be made: [a] Additions of ruthenium are very effective cent ruthenium, see Figure 1(d), starts at -20°C. in reducing the martensitic transformation tem- The R-phase exists over a wide temperature peratures of titanium-nickel based ternary alloys. range, down to liquid nitrogen temperatures. The B2-phase can be stabilised by the addition The martensitic transformation scheme, Figure of approximately 2 atomic per cent ruthenium. 4, shows that the B2-phase is approximately sta- (The same results can also be expected from bilised at room temperature in alloy containing additions of osmium.) 2 atomic per cent ruthenium. The substitu- [b] Higher concentrations of rhodium and irid- tion of ruthenium for nickel results in a lower- ium (6 atomic per cent) are required to stabilise ing of all critical transformation temperatures, the B2-phase. but the decrease in the TRtemperature occurs [c] Platinum and palladium do not appear to less acutely than the decrease in the tempera- stabilise the B2-phase at room temperature. tures which indicate the transformation range Conclusions The substitution of ruthenium for nickel in titanium-nickel-ruthenium ternary alloys along the TiNi-TiRu section, as examined by physical and chemical analyses, results in the stabil- 1 isation of the high temperature B2-type phase at room temperature for alloys containing at least 2 atomic per cent ruthenium. Alloys containing 0.5 to 2 atomic per cent ruthenium undergo a two stage transformation. In continuation of our work with the platinum group metals, we intend to study phase equi- 1804 I libria in the titanium-nickel-ruthenium system 0 2 4 6 8 10 TiNi RUTHENIUM ADDITION, at.% both experimentally and by calculation, and fol- Fig. 5 Variation of the microhardness with lowing that calculate the effect of ruthenium on composition for the TiNi-TiRu alloys, based the martensitic transformation in equiatomic on titanium-nickel alloy titanium-nickel compound. Data obtained from

Platinum Metals Rev., 1995,39, (4) 178 the titanium-nickel-ruthenium alloys will make we expect that it will sharply decrease the it possible to forecast the effect of osmium on transformation temperatures in a way similar to martensitic transformations in TiNi-based alloys; that of ruthenium. References 1 Yu. V. Kudryavtsev, E. L. Semenova, L. A. 6 V. E. Listovnichiy, V. P. Brodskiy and P. F. Fenyuk, Tretyachenko, “The Stable and Metastable Phases “The Automated System of Measurements of the inMaterials”,Kiev,IPMASUkr. SSR, 1987, 138 Electrical Resistance and Thermo-e.d.s. 2 E. L. Semenova and Yu. V. Kudryavtsev,J AUqs Temperature Dependence”, J. Zav. Lab., 1987, Comp., 1993,203, 165 53, 47 (in Russian) 3 A. A. Klopotov, E. V. Kozlov, Yu. V. Kudryavtsev 7 A. S. Sawinov, V. N. Khachin, andV. P. Sivokha, and E. L. Semenova, “Effects of Shape Memory Izv. Vys. Uch. Zav., Ser. Fiz., 1983, 7, 34 (in and Superelasticity and their Application in Russian) Medicine”, Tomsk University, Tomsk, 1989, 168 8 S. G. Fedotov, N. N. Bashanova and N. F. (Abstracts of I All-Union Conference) (in Russian) Zhebeneva, Izv. Acad. Nauk SSSR, Ser. Met., 4 E. L. Semenova, L. A. Tretyachenko, D. B. 1981, 4, 147 (in Russian) Chernov and Yu. V. Kudryavtsev, “Phase 9 S. Miyazaki and K. Otsuka, Phi&s. Mag. A, 1984, Equilibria, Structure and Properties of Alloys”, 50, 393 Naukova Dumka, Kiev, 1990, 101 (in Russian) 10 C. M. Hwang, H. B. Salamon and C. M. Wayman, 5 N. M. Matveeva, I. E. Lyuboserdova, V. N. Philos. Mag. A, 1983,47,2, 177 Khachin, V. P. Sivokha and D. B. Chernov, “The 11 K. Enami, T. Yoshida and S. Nenno, “Proc. of Rare Metals Alloys with Special Properties: Rare- the International Conference on Martensitic Earth and Precious Metals”, Nauka, 1983, 163 Transformations”, The Japan Institute of Metals, (in Russian) Osaka, Japan, 1986,1032 Noble Metals Utilised in Drugs and Healthcare Metal Compounds in Cancer Therapy, Metals in Health and Disease Series - Volume 1 EDITED BY SIMON P. FRICKER, Chapman & Hall, London, 1994,256 pages, ISBN 0-412-54280-3, k55.00 There are about 92 elements in the Periodic undergoing clinical trials, aimed at lessening Table to be understood and exploited for med- unpleasant side effects, exploring other speci- ical purposes, and this is the first volume in a ficities, and introducing oral application. new “Metals in Health and Disease Series”. The particular success of platinum in the treat- Metals in particular have an immense potential ment of testicular, ovarian and other soft tis- - as is shown by the function and diversity of sue cancers is well documented. While platinum trace metals in metalloproteins, and until has many advantages there is no reason why other recently many, if not most, have been overlooked. metals should not find similar application. Thus The series sets out to explore the beneficial reviews on gold (C. F. Shaw), ruthenium com- roles of metals in health and disease. Each vol- pounds (G. Sava), rhodium, iridium and pal- ume of invited reviews will target a specific area, ladium (R. G. Buckley) are authoritative and accumulating and evaluating published data. provide a valuable update where the approach The series is aimed at graduates, post-gradu- and general understanding is less well docu- ates and researchers. It will also be of interest mented. The often unique properties of metals to a much wider readership. offer many opportunities. Metals can participate Of course, Pt(I1) is very much a success story, in biological redox reactions, undergo ligand and not surprisingly features in the first two (S. substitution with biological molecules with a I?. Fricker and L. R. Kelland) of ten reviews. specific stereochemistry about the metal cen- It is an interesting example of serendipity - tre and with a controlled reactivity. Some met- Rosenberg’s initial experiments in 1965 were to als have radioactive isotopes, with potential for find if electrical fields applied across platinum tumour imaging or therapy. Further chapters electrodes effected the growth of Escherichia coli. cover other metals, adding diversity to the text. In 197 1 cisplatin entered clinical mals, and today This book is presented in an attractive, pro- the area is still extensively researched to achieve fessional and readable manner. For those in the better understanding, and to identify better area it is an essential readingheference work. For applications. Cisplatin and carboplatin are now others it will provide an awareness of a growth top selling anti-cancer drugs. No doubt they will area. It is an important series to launch at this be bettered by other preparations, some already time and is strongly recommended. A.G.S.

Platinum Merals Rm., 1995, 39, (4) 179 ABSTRACTS of current literature on the platinum metals and their alloys

PROPERTIES Structure of Two-Dimensional Conductor of Sr,RhO, Formation of Thin Films of Platinum, M. ITOH,T.SHIMURA,Y.INAGUMAalldY.MORn,~Solid Palladium, and Mixed P1atinum:Palladium Stare Chem., 1995, 118, (l), 206-209 Nanocrystallites by the Langmuir Monolayer The structure of the two-dimensional conductor Technique Sr,RhO, was refined by powder X-ray dfiaction at room temperature. Sr,RhO, crystallises with the sym- F. c. MELDRUM, N. A. KOTOV and J. H. FENDLER, Chem. MUEX,1995,7, (6), 11 12-1 116 metry of space group 14,/acd, isosmdwith Sr,IrO,, Chloroform solutions of colloidal Pt, Pd and mixed and the lattice parameter a = 0.54516(1) and c = WPd = 1: 1 particles prepared by solvent extraction 2.57539(4) nm. The structural data were similar to were dispersed on a H,O subphase in a Langmuir those for semiconducting and amifemmagneticSr,IrO.,. trough to generate particulate films 30A thick. A great amount of the stabiliserwas incorporated in the films, CHEMICAL COMPOUNDS thus preventing a completely close-packed arrangement of the metal particles. First Octahedral Platinum Cluster: Structure as a Function of Electron Count in & Clusters Structural Investigation of Bimetallic Rh-Pt Nanoparticles through X-Ray Absorption L HAO, G. J. SPIVAK, J. XIAO, J. J. VITTAL and R. J. PUDDEPHAlT,J Am. Chem. SOC., 1995, 117, (26), spectroscopy 7011-7012 L. E. ALEANDRI, H. BON"N, D. J. JONES, J. RICHTER Two new types of Pts clusters, interconvertibleby the andJ.Roz&RE,J. Mate+. Chem., 1995,5, (5), 749-752 gain or loss of two electrons, and one having octahe- EXAFS studies of an isolated Rh-Pt colloid, Rh, Ib dral stereochemistry, are reported. The dark red-pur- showed mixed-metal shells, with the environment ple, &-sensitive cluster [Pts(p-CO)&dppm),] (dppm around the Rh absorber consisting of 3.5 Rh atoms = Ph2PCH2PPh2)(1) was prepared by reduction of at a distance of 2.72 A and 4.7 Pt atoms at 2.74 A, [PtCI2(SMe,),]and [PtCl,(dppm)] with NaBK under and around the Pt absorber 3.6 Rh at 2.72 A and CO, in high yield. (1) has two Pt,(p-CO), triangles 8.3 Pt atoms at 2.75 A. The average co-ordination bridged by 3 p-dppm ligands, with Dlhsymmetry and number was lower than the 12 expected for a f.c.c. is easily oxidised to give the cluster cation [Pt6(CO)& structure. The system is best described as a nanopar- dppm),]" with terminal carbonyl ligands. ticulate Rh-Pt alloy, surface rich in Rh. Reductive Reactions in Synthesis of Low- Solid-state Reaction in Pd/ZnSe Thin Film Valence Platinum and Palladium Complexes Contacts N. W. KOZITSYNA and I. I. MOISEEV, USP. Khim., 1995, K. J. DUXSTAD, E. E. HALLER, K. M. W, E. D. BOURRET, 64, (l), 51-65 J. M.WALKER, x. w. LIN and J. WASHBURN, Appl. Fhys. The use of reductive reactions of Pt(I1) and Pd(I1) Len., 1995, 67, (7), 947-949 complexes in the synthesis of complexes containing Solid-state reactions in Pd thin film contacts on ZnSe the metals in low-valence states (0 5 n 5 2) with x- initiated at the PdZnSe interface by thermal anneal- acceptor ligands phosphines, phosphides, phenanthm- ing at 200"C, formed a tetragonal ternary phase line and dipyridyl is discussed. Transformation of rerz- Pd5+ZnSewhich had highly oriented grains and was phosphine ligands with a reductive agent and X-ray data stable up to an annealing temperature of 400°C. The for the mono- and polynuclear complexes of Pt and Pd PdZnSe interface was thermally more stable than the in low oxidation states are reviewed. (138 Re&.) correspondingPdGaAs and PdSi smctures. Pdsemi- conductor interfacial phenomena were studied. Synthesis of Large Palladium Clusters. The Preparation of Pd31(CO)B(PR3)1z(R = Et, Bun) Observation of Internal Structures of and PdN(CO)&'Et& Martensites of Fe-Rh Alloys E. G. MEDNIKOV and N. I. KANTEEVA, Izv. Akad. Nauk N. TAKAHARA, M. TAKAHASHI and R. OSHIMA, 3 Jpn. Rosii, Set Khim., 1995, (l), 167-170 Inst. Met., 1995, 59, (6), 599-606 The Pd,,(C0)28L,, cluster (L = PEt,) was prepared Internal structures of the martensites of Fe-5 at.% Rh by reacting Pd,o(CO)12L,with CF,COOH-Me,NO, and Fe-25 at.% Rh (1) were examined by XRD, opti- CF,COOH-H202,and Pd(OAc)2-MesrT0and Pd,(dba), cal microscopy and TEM. Both alloys showed sur- mixture (dba = dibenzylidenacetone). Tri-n-butylphos- face reliefs, which result from martensite transfor- phine Pd,8(CO),8(PBu,),,was synthesised by the reac- mation. The martensites are of a dislocated lath type. tion of Pdlo(CO),,(PBu,),with Me,NO. The reaction In (1) alloy twinning shear is associated with the lat- of Pd,(C0)5L, with Pd,(dba), yielded clusters tice invariant shear of the transformation. Pd,,(CO),,L,, and Pdia(CO)I,L.

Platinum Metak Rev., 1995,39, (4), 180-185 180 One-Pot Synthesis and X-Ray Studies on Attempts to Modify an Electrode with a Cyclic Oligobipyridines and One of Their Conducting Platinum Cluster Compound Dinuclear Ruthenium Complexes L. XU, F. LI and S. DONG, Ekctroanalysis, 1995, 7, (8), C. KAES, M. W.HOSSEINI, R. RUPPERT, A. DE CIAN and 734-737 J.FISCHERJ. Chem. Soc., Chem. Commun., 1995, (14), A conducting Pt cluster compound K, &(C,O,), was 1445-1446 electrochemicallysynthesised on a glassy C electrode A one-pot synthesis of three new macrocycles con- through the electro-oxidation of KzPt(CzO,), in an taining two, three or four 2,2'-bipyridine units is aqueous medium using slngle potential step and cyclic described. A homodinuclear RU" complex was pre- voltammetry methods. The excellent conductivity pared in almost quantitative yield by reacting one of of the fibrous material that grew on the electrode was the macrocycles with 2 equiv. of Ru(bipy),Cl2 in a observed voltammetrically. Each conducting fibre in butanol-H,O solution. Precipitation of the PF6 salt contact with the electrode could act as an ultrami- from an aqueous solution gave the pure complex as a croelectrode, and the electrode behaviour changed mixture of diastereoisomers. The X-ray structure of from a plain to an ultramicroelectrode array. one of the diastereoisomers of the dmuclear Ru complex shows two metal centres held in close proximity. Absorption-Desorption of Deuterium at Pd95%-Rh5% Alloy. I: Environment and Chiral [R~(pp)~(C0)~]~'Species (pp = Temperature Effects Bidentate Polypyridyl Ligand) and Their Use G. MENGOLI, M. FABRIZIO, C. MANDUCHI, E. MILU and G. in the Stereoselective Synthesis of Ligand- ZANNONI, 3. Electroanal. Chem., 1995, 390, (1-2), Bridged Dinuclear Complexes 135-142 T. J. RUTHERFORD, M. G. QUAGLIO?TO and F. R. KEENE, The gas phase and electrolytic loading of 5%Rh-Pd Inorg, Chem., 1995, 34, (15), 3857-3858 alloy with Dzwere studied. Gas loading was performed The decarbonylationof chiral [RU@~)~(CO)~]~'@p= isochorically under 900 mbar Dz,by decreasing the bidentate polypyridyl ligands) in the presence of excess temperature from 900 to 20°C. The absorption was pp showed stereoretention in the [RU@~),]~'prod- measured at 20°C when the w]: [Me] ratio exceeded uct. Under the same conditions, its reaction with chi- the typical value for pure Pd. Electrolytic insertions ral [RU(~~')~(BL)]'+centres @p and pp' may or may of DZwere carried out potentiostatically in alkaline not be identical; BL = bridging ligand) allows the syn- DzOelectrolytes, giving maximum p]:[Me] ratios at thesis of specific diastereoisomeric forms of the 25"C, while at 90°C alloy deuterides of large [D] :[Me] dmuclear species [@p)zRu(BL)Ru(pp')z]4'. ratio were obtained. A Novel Ru(W)/Ru(IV) Mediatory System ELECTROCHEMISTRY for Electmoxidation of Primary and Secondary Alcohols, Leading to Aldehydes and Ketones Methanol Oxidation at Electrochemically s. TONI and A. YOSHIDA, Chem. Lett., 1995, (5), Oriented Platinum Electrodes in Acidic 369-370 Medium A soluble Ru(VII)/Ru(IV) redox system in MeCNl A. A. ELSHAFE1,J. Phys. Chem. (Miinchen), 1995,190, H,O-Bu,NOH-(Pt/Pt) was found to be a mild oxi- (II), 231-239 dising system for the electrochemical conversion of Methanol oxidation was studied as a structure sen- primary and secondary alcohols into their corre- sitive process on different Pt surfaces: polycrystalline sponding aldehydes and ketones under basic condi- Pt and reproducibly prepared electrochemically ori- tions. Direct evidence on the working of the Ru(VI1)l ented Pt surfaces. The fabrication of Pt surfaces with Rumredox as a mediator system was obtained from preferred orientations or different surface concen- UV spectroscopy. trations of low index planes depends on the electrochemical treatment. Bulk MeOH oxidation depended PHOTOCONVERSION both on the predomination of one low index plane and on the ratio of the surface planes. Acid-Base Behavior of the Ground and Excited States of Platinum(I1) Complexes of Contribution to the Interpretation of the Quinoxaline-2,3-dithiolate Multistep Cathodic Reduction of Oxygen at s.D. CUMMINGS and R EISENBERG, Inorg. Chem., 1995, the PtlZirconia Base Electrolyte Interface 34, (13), 3396-3403 at High Temperature Studies of the pH-dependent absorption and emis- G. B. BARBI, Bn: Bumenges. phys. chm., 1995,99, (5), sion behaviour of Pt(qdt):- (1) and Pt@hen)(qdt) (2) 741-748 (qdt = quinoxaline-2,3-dithiolate and phen = 1,lO- The multistep cathodic reduction of 0,molecules at phenanthroline) showed pH-dependent changes in high temperatures at the porous Pt/YzO, stabilised both their charge-transfer absorption and emission ZrOzsolid electrolyteinterface was analysed by steady spectra, which were attributed to protonation of the state polarisation. For very thin and porous layers and qdt ligand at the imine N. For (l), single protonation 0,mixtures of 2 1% Oz,the rate of the overall process leads to a large red shift (2582/cm), but for (2) the was controlled by the electrodelelectrolyte interfa- lowest-energy excited state involves charge transfer cial diffusion of neutral and/or single ionised atoms. from an orbital of Pt(d)/S(p) to a phen x* orbital.

flatanum Metak Rev., 1995, 39, (4) 181 Electronic Spectra and Photochemistry of APPARATUS AND TECHNIQUE Trichlorostannyl Complexea of Ruthenium(II) and Osmium(I1) Calorimetric Measurement of the Energy V. PAWLOWSKI, H. KUNKELY and A. VOGLER, Inorg. Chh. Difference between Two Solid Surface Phases Acta, 19955 234, (1-2), 55-60 Y. Y. YEO, C. E. WARTNAJ3Y and D. A. KING, ~CZi??ZCe,1995, The absorption spectra and photochemistry of 268, (5218), 1731-1732 [M(SnCl&]", [M(SnCl,),Cl]" and [M(SnCl,)m' , The energy difference between two solid surface swc- where M = Ru, 0s; AN = acetonitrile, in acetoni- tures was measured using a single-crystal surface uiie were studied. It is suggested that the lowest energy calorimeter which is a clean Pt{ 100) surface recon- transitions are largely of the inualigand type. The phc- structed to a stable phase where the surface layer of tolysis in acetonitrile leads to substitutions of SnCl, Pt atoms has a quasi-hexagonal structure. By com- or in the case of [Ru(SnCl,),]* to a ligand fragmen- paring the heats of adsorption of CO and C,H, on this tation as primary photoreactions. [M(SnCl,)r(AN)2]' stable Pt{100)-hex phase with those on a metastable was the terminal product of all the photoreactions. Pt{lOO}-(l x 1) surface, the energydifferencebemeen the two clean phases was measured as 20 f 3 and Ruthenium(II) tris-(2,2'-bipyridine)-Speciecific 25 k 3 kJ/mole of surface Pt atoms. Extrinsic Lyoluminescences of X-ray Irradiation Colored and Electrolytically PlatinUmlGIassy Carbon Electrode as Detector Colored Alkali Halides for Liquid Chromatographic Determination S. KULMALA,A. HAKANEN, P. RAERINNE, A.KULMALA and of Hydroxyl-ContainingCompounds K. HAA~AKKA,Anal. Chim. Acta, 1995, 309, (1-3), I. G.CASELLA,Anal. Chim. Acta, 1995,331, (I), 3746 197-2 10 A Pt-modified glassy C electrode (CME) was studied Short-lived solidsolution interfaces, which are suf- as an amperometric detector for mono- and polyhy- ficiently energetic to initiate the radiative 'MLCT- dric compounds in flowing streams, including liquid based transition lyoluminescence (LL) of Ru(I1) tris- chromatography. The Pt-CME showed good sensi- (2,2'-bipyridine)chelate can be produced on dissolving tivity and time stability. The electrode response was X-ray irradiation coloured or electrolytically coloured stable showing a signal loss of C 5% after 8 h trials. alkali halides in H20. Using Ru(bpy),z' as a model lyoluminophore, the basis of using LL as a new ana- Morphologic and Spectroscopic Characteriz- lytical tool is discussed. The eminsic LL of F-coloured ation of Porous PtlGaAs Schottky Diodes by alkali halides allows detection of luminescent com- Scanning Tunnelling Microscopy pounds at trace levels in aqueous solutions. J. MASO,N. BARNIOL F. PEREZ-MURANO and x.AYMERICH, Thin Solid Films, 1995,261, (1-2), 299-306 Control of Photosubstitution in Dinuclear The porous character of the Pt film of Pt/GaAs Ruthenium Polypyridyl Complexes by Choice Schottky diodes used as NH,gas sensors was studied of Bridgii Ligand using STM. Electrical measurements were also per- H. P. HUGHES and J. G. vos, hrg. Chem., 1995,34, ( 15), formed in very localised regions of the surface.The 40014003 diameter of the Pt grains of the porous 6lm was found Photolysis of [(R~(bpy)~)~(bpzt)]"(Hbpzt is 33- to depend on its thickness. bis(pyrazin-2-yl)-l,2,4-triazole) resulted in a unique labilisation of the metal moiety bound to the tria- Tunable, Long-Wavelength PtSilSiGelSi zole N4 site. This is contrary to results obtained for Schottky Diode Infrared Detectors the analogous compound based on the 3,5-bis(pyridin- J. R. JU~ENEZ,x. mo,J. c. STURM and P. w. PELLEGRINI, 2-yl)-1,2,4-mazole ligand for which both the N1 and Appl. Phys. Len., 1995, 67, (4), 506-508 N4 sites were subject to photochemical substitution. The fabrication is reported of ptype PtSi/SiGe/Si This is explained by changes in the rate of relaxation Schottky diodes with barrier heights (from photore- to the lowest excited state, due to the different natures sponse) that are lowered (relative to PtSi/Si) and are of the luminescent properties in these complexes. highly dependent on the applied bias. Variability in barrier height was obtained by using the SiGe/Si valence band offset as an additional barrier close to the PtSi/SiGe ELECTRODEPOSITION AND Schottky barrier. The total effective barrier can then SURFACE COATINGS be altered by adjusting the applied reverse bias. Rhodium Plating Study of the Adsorptive Voltammetric R J. MORRISSEY, plat. Surf: Finish., 1995,82, (8), 69 Behavior of the RhU'-5-Br-PADAPComplex Rh can be evaporated under vacuum, but is mostly elec- C. WANG, C. HONG and H. LI, Electroanalysis, 1995, 7, trodeposited. Electroplatingsolutions for Rh are highly (S), 759-762 acidic, and are usually based on the sulphate or phos- The adsorptive voltammetric behaviour of the Rh"'- phate. For decorative applications, Rh plating solutions 2-(5-bromo-2-pyridylazo)-5-diethylaminophenolcom- contain - 2 gA Rh and - 20 mv1 concentrated H,SO,, plex was studied by linear scan in a solution of NaOAc, at 1-5 NdmZand at 4045°C. Rh can be plated fimn HOAc and ethanol. This method provides sensitive molten cyanide systems to a thickness of > 100 p.Rh selective adsorptive stripping voltammetry for the deposits are non-toxic and hypoallergenic. detection of 7.8 x 10 '- 9.7 x lO-'mol/l traces of Rh.

Platinum Metals Rm., 1995, 39, (4) 182 Novel Thick-Film pH Sensors Based on Naphthalene Hydrogenation over Pt/AI,O, Ruthenium Dioxide-Glass Composites Catalyst in a Trickle Bed Reactor H. N. MCMURFWY,P. DOUGLAS and D. ABBOT, Sens. T.-C. HUANG and B.X. KANG, Znd. Eng. Chem. Res., Actuators B, 1995,28, (l), 9-15 1995,34, (7), 2349-2357 Composite electrodes comprising thick films of 30 Naphthalene dissolved in different volatile solvents f 10 p Ru0,-glass composite on a Pyrex substrate was hydrogenated over Pt/Al,O, catalyst in a trickle were made and showed a near Nernstian dependence bed reactor. The activity and selectivity were stud- of potential on pH in aqueous buffer at pH 2-12 ied with various H, and feed flow rates at 5 13 K and and at a Ru0,:Pb borosilicate glass ratio of 1: 1. The 5.17 MPa. The activity of naphthalene hydrogena- electrodes displayed a maximum hysteresis of 30 mV tion increased with increasing wetting efficiency, and and a response time of - 90 s. The electrodes are the selectivity of cis-decalin decreased with increas- porous and the response time increased with the ing solvent volatility. Ru0,:Pb borosilicate glass ratio in the composite. Hydrogenation of Oxygen-Containing Acyclic Compounds Using Finely Dispersed Catalysts HETEROGENEOUS CATALYSIS Based on Platinum Group Metals A Novel Aminoalcohol Modifier for the T. N. ANTONOVA, A. A. KUNITSKII, E. M. CHABUTKINA, Enantioselective Hydrogenation of Ethyl G. N. KOSHEL', A. L. SOKOLOV and s. P. KOROVINA, Neftekhimiya, 1995, 35, (l), 49-55 Pyruvate on Pt/Alumina Studies of the hydrogenation of the double bonds in B. MLNDER, T. MALLAT, A. BAKER, G. WANG,T. HEINZ and 5,6-epoxy-&-cyclooaene, 5-cyclooctene- 1,2diol and A. PFALTZ,J cad., 1995, 154, (2), 371-378 the reduction of aqueous cyclooctylhydroperoxide A chiral modifier, (R)-2-(1-pyrrolidinyl)-l-(l-naph- were performed using finely dispersed Pt group metal thy1)ethanol (PNE) was prepared and tested in the catalysts, such as >5%Pt/C, 1-5%PdC and 2-5%Rh/ enantioselectivehydrogenation of ethyl pyruvate over C. These finely dispersed catalysts were highly effec- Pt/Al,O,. An enantiomeric excess in @)-ethyl lactate tive in producing cycloalkanol and cycloalkanone. of < 75% was obtained. The optimum reaction conditions were 1-10 bar Hzpressure, 0-25°C and a Vapour-Phase Hydrodehalogenation of catalyst loading 2 15 gil. The efficiency of PNE was Chlorobenzene over Platind-BEA Zeolite shown by the very low modifier:reactant molar ratio, E. J. CREYGHTON, M. H. w.BURGERS, J. c. JANSEN and H. 1:30,000, to obtain maximum enantioselectivity. VANBEKKUM, Appl. Catal. A: Gen., 1995, 128, (2), a 275-288 Structural Characterization of Model Studies of Pt/H-BEA zeolite and Pt/AI,O, catalysts Catalyst: PtlAI,OJNiAl( 110) during the vapour-phase hydrodehalogenation of T. BERTRAMS, F.WINKELMA", T. UTIICH, H.-1. FREUND chlorobenzene showed them to be highly active in the andH.NEDDERhEYER, &I$ Sd., 1995,331-333, (part hydrogenolysis of the C-halogen bond. Deactivation B), 1515-1519 of Pt/H-BEA is due to acid catalysed oligomerisation The condensation of Pt was studied on clean reactions and coke formation. Coke formation dimin- "(1 10) and on a thin ordered Al,O, film grown on ished and catalyst stability improved by replacement NiAI(ll0). On Al,OJNiAI(l 10) and up to a cover- of Brclnsted acid sites in the Pt catalyst by Na ions. age of one monolayer, Pt forms highly dispersed two- dimensionalislands with an average diameter of 10-30 Skeletal Reactions on n-Hexane over Pt-Nay, A whose density increased with coverage. For higher Pt/Si02,HY, and Mixed Pt/Si02+ W Catalysts Pt coverage the formation of three-dimensional Pt Z. PAhL, Z. ZHAN, I. MAN"GER and W. M. H. SACHTLER, clusters was observed. Annealing of the Pt-covered J Caral., 1995, 155, (l), 43-51 surface led to Pt diffusion into the oxide film. On The activity and selectivity of three 8%PtR\TaYcata- "(1 10) and up to 1 monolayer, 2-dimensional lysts calcined at 633, 723 and 823 K were studied growth of Pt with constant island density was observed. with n-hexane as the model reactant at 603 K and subatmosphericpressure. The activity of all the l"aY The Positive Effect of Hydrogen on the catalysts was superior to that of EUROPT-1 and they Reaction of Nitric Oxide with Carbon deactivated more slowly. The sample calcined at 633 Monoxide over Platinum and Rhodium K had the highest dispersion and the highest aroma- Catalysts tisation selectivity. R. DOWELMA", N. w. CANT and D. L. TRIMM, Catal. LRtt., 1995, 32, (3,4), 357-369 First Heck Reactions of AryldiazoniumSalts The effect of adding 3304930 ppm H, to a reac- Using Heterogeneous Catalysts tion mixture of NO and CO over Pt and Rh cata- M.BELLERand K KWIN,s)?Zk%t, 1995, (5), 441442 lysts was studied at 200-250°C. The addition of H, A very simple and practical Heck reaction of diazo- results in a large increase in the conversion of both nium salts and acrylic acid esters, based on heteroge- NO and CO. The equation for the reaction accounts neous Pd catalysts supported on C, AlzO,, Si02and for the 50-100% of CO, formed with Pt/AI,O, and BaSO, has been developed. Chamic acid esters were the 2&50% with Rh/Al,O,. The process arises by for- obtained under very mild conditions in good to excel- mation of isocyanic acid on the metal followed by lent yields. No addition of a base or of phosphane lig- hydrolysis to CO, and NH, on the support. ands was needed for good conversion.

Platinum Metals Rw., 1995, 39, (4) 183 High Activity of CO Oxidation over HOMOGENEOUS CATALYSIS Nanocrystalline CuO-Pd/~-Al,O,Catalysts Prepared by the y-Radiation Method Palladium-Catalyzed Stereoselective Y. ZHU, P. LIN, Y. QIAN, s. w, z. CHEN and M. ZHANG, AllylFminocyclization and 1,3-Butadien-2- Chin. J. Chem. Phys., 1995,8, (3), 274-278 ylammoqchtion of Allenyl Twylcarbamates The nanocrystalline CuO (8 wt.%, 12 nm)-Pd (0.5 M. mum,s. TAN- and Y. TAMARU, J. Org. Chem., wt.%, 10 nm)/y-Al,O, catalyst prepared by the y-radi- 1995,60, (12), 3764-3772 ation method was very active in CO oxidation reac- Pd catalysts, PdCI2(PhCN),or Pd,(dba) ,.CHCI, (dba tions. It started operating at 110°C; its light-off tem- = dibenzylideneacetone) catalysed an allylaminocy- perature was 145°C and 100% CO conversion was clisation of 2,3-butadienyl tosylcarbamates (1) with obtained at 148°C. The catalyst showed thermal sta- allylic chlorides in the presence of Et,N or K2C0,base bility in its activity after thermal treatment at g 750°C. in THF at room temperature to give selectively trans- 4,5-disubstituted 2-oxazolidinones in good yields. Structure and State of Surface of Under similar conditions, Pd(PPh,), catalysed an Aluminopalladium Catalysts fiom bis(K-Ally1 N-allylation of (1). In the absence of an allylic chlo- Palladium Chloride) ride, Pd(PPh,), and PdCl,(PhCN), catalyse a for- N. v. PEWS, G. D. ZAKUMBAEVA and T. D. LEvINTOVA, mal dimerisation of (1) to give C,-triene-substituted Nejiekhimiya, 1995, 35, (2), 141-147 2-oxazolidinones in moderate to good yields. Studies of the Pd/y-Al,03catalyst prepared by reducing (C,H,PdCI), with N,H,.H20 on y-Al,O, in aque- Asymmetric Hydrosilylation of 1-Alkenes ous ethanol solution, followed by drying in alcohol, Catalyzed by Palladium-MOP showed the formation of highly dispersed Pd on the Y. UOZUMI, K. KITAYAMA, T. HAYASHI, K. YANAGI and E. surface of the support. The active phase was of zero- FUKWO, Bd. Chem. SOC.~.,1995,68, (3), 71>722 valence order, containing low-valent ionic Pd forms, Asymmetric hydrosilylation of 1-alkeneswith trichlo- which were stabilised by organic ligands. The cata- rosilane at 40°C in the presence of 1 x 10 ’ or 1 x 10 ‘ lyst was highly reactive in liquid-phase hydrogenation. molar amounts of Pd-MOP catalyst proceeded with good regioselectivityand with high enantioselectivity Palladium-Ceria Catalysts: Reversibility of to give high yields of 2-(trichlorosi1yl)alkanes. The Hydrogen Chemisorption and Redox catalyst was prepared in situ from [PdCI-(q’-C3Hr)]2 Phenomena and (S)-2-diphenyfphosphinc-2’-methoxy- 1,l ’-binaph- A. BENSALEM, F. BOZON-VERDURAZ and v. PERRICHON, thy1 ((8-MeO-MOP). Oxidation of the C-Si bond J. Chem. SOC.,Faraday Trans., 1995, 91, (14), gave optically active 2-alkanols (87-97% ee). 2 185-2 189 Stereoselective Addition of Carboxylic Acids Studies of the H, interaction with Pd/Ce02catalysts to Electron Deficient Acetylenes Catalyzed by showed that the ratio Hi, : Pdtotal,H,, = irreversibly adsorbed H, is 2.5-3.5. This is due to H spillover from the PdMo,S, Cubane-Type Cluster Pd to CeO,. The uptake of H by CeO, resulted in T. WAKABAYASHI, Y. ISHII, T. MURATA, Y. MIZOBE and its complete surface reduction at room temperature, M. HIDAI, Tetrahedron Len., 1995,36, (31), 5585-5588 while bulk reduction started at 473 K. The reoxida- The mixed-metal sulphide cubane-type cluster com- tion ratio depended on the outgassing temperature. plex [PdMo,S,(tacn),CI] [PF,,], (tacn = 1,4,7-triaza- cyclononane) was found to be a highly efficient and Catalytic Decomposition of N,O over selective catalyst for the addition of carboxylic acids Rhodium-Loaded Metal Oxides to acetylenes with electron-withdrawing groups. The J. 01, A. OBUCHI, A. OGATA, H. YAGITA, G. R. BAMWENDA corresponding trans addition products were exclu- and K. MIZUNO, Chem. Len. Jpn., 1995, (6),453-454 sively obtained in good yields under mild conditions Studies of catalytic decomposition of N20to N2and in the presence of a catalytic amount of methylamine. 0, on Rh-loaded metal oxide catalysts showed that Rhodium( I)- and Palladium(0)-Catalyzed WZnO had the highest activity. An air-pretreated Carbonylation of Triarylbismuthines with 0.5 wt.% WZnO catalyst was the most active, giv- Carbon Monoxide via a Possible Oxidative ing a reaction rate of 4.0 x 10‘ pmol (N20)/ghunder 950 ppm of N20and 5% of 0, at 300°C. Addition of a Carbon-Bismuth Bond to Rhodium(1) and Palladium(0) Selective Hydrogenation over Ruthenium c. s. CHO, Y. YOSHIMORI and s. UEMURA, Bull. Chem. Catalysts SOC.Jpn., 1995,68, (3), 950-957 P. KLUSON and L. CERVENY, Appl. Cad.A: Gen., 1995, Triarylbismuthines reacted with CO at atmospheric 128, (l), 13-31 pressure in acetonitrile at 25°C in the presence of a A review is given of the preparation, characterisa- catalytic amount of a Rh compound, such as tion and activities of Ru catalysts used in the selective [RhCl(CO),],, RhCII.3H20 and [RhCI(COD)],, hydrogenation of carbonyl groups in the vicinity of where COD is cyclooctadiene, to give high yields of conjugated or isolated double bonds, for the pro- the corresponding diary1 ketones and methyl esters. duction of a,P-unsaturated alcohols. The effects of With MeOH solvent, methyl benzoates are also pro- promoters, particle size, inorganic and organic mod- duced. Oxidative addition of a C-Bi bond to %(I) ifiers, and catalyst supports are discussed. (137 Refs.) and Pd(0) is the major step in the carbonylations.

Platinum Metals Rev., 1995, 39, (4) 184 Transformations of Formaldehyde and Chiral Ruthenium(JI)-Bis(2-oxazolin-2-yl)- Glycolaldehyde during Rhodium-Catalysed pyridine Complexes. Asymmetric Catalytic Hydroformylation of Formaldehyde Cyclopropauation of Olefins and Dimacetates N. N. EZHOVA, G. A. KORNEEVA, E. v. SUVINSKII and R. H. NISHNAMA, Y. ITOH, Y. SUGAWARA, H. MATSUMOTO, A. ARONOVICH, Izv. Akud. Nuuk Rosii, Ser. Khim., K.AOKI and K. ITOH,Bull. Chem. SOC.Jpn., 1995,68, 1995, (l), 75-78 (9,1247-1262 The hydroformylation of formaldehyde to gly- The title chiral Ru(I1) complex, which was prepared colaldehyde (GA) catalysed by RhC1(PPh3),, in situ from optically active bis(2-oxazolin-2-yl)pyri- RhC1(CO)(PPh3),and RhCl, + PPh, system in N,N- dine (Pybox-ip) (1) and [RuCl,(pcymene)], (2), exhib- dimethylacetamide was studied. The hydroformylation ited efficient activity for the asymmetric cyclopropa- was accompanied by the K ' 0-Tishchenko reac- nation (ACP) of styrene and a number of diazoacetates, tion, hydrogenation of CH,O to MeOH, condensation to give the corresponding trans- and cis-2-phenylcy- of CHzO wirh GA to powdlydaCrCi, and dimeri- clopropane-1-carboxylates in good yields of 6687%. sation of GA. The formation of polyoxyaldehydes was A mixture of (1) and (2) in ethylene produced the the predominant side reaction, probably proceeded by truns-RuCl,(Pybox+) (ethylene) complex which also GA coordination with a Rh atom. RhCl, + PPh, cata- proved to be a powerful catalyst for ACP. lyst gave the best results for CH,O hydroformylation. At the substrateconversion to 6247%, the selectivity for GA formation was 96% and the yield was 6&65%. ELECTRICAL AND ELECTRONIC ENGINEERING Strong Electronic Effects on Enantioselectivity in Rhodium-Catalyzed Hydroborations with Magneto-Optical Enhancement in Novel Pyrazole-Containing Ferrocenyl Ligands Pt/(Ni,,Co,) Multilayers A. SCHNYDER, L. HINTERMA" and A. TOGNI, Angew. R. KRISHNAN, M. NYVLT, v. PROSSER, M. SEDDAT, z. Chem., Znr. Ed. Engl., 1995, 34, (8),931-932 SMETANA, M. TESSIER and s. VISNOVSKY, J. Map. &+ Studies of the Rh catalysed hydroboration of styrene Mugn. Muter., 1995, 148, (1-2), 283-284 with catecholborane using [Rh(cod),]BF, catalyst Magneto-optical (MO) polar Kerr rotation (PKR) (cod=cyclooctadiene) showed the highest enantio- and ellipticity spectra of Pt/(Ni, .Cox) multilayers with selectivityyet for a hydroboration (98% ee) obtained x = 0,0.3 and 1, prepared by evaporation under UHV, with the pyrazolyl-containing ferrocenyl ligand con- were studied. Layers formed at the Pt-magnetic layer taining Me, H and 4-CF3C,H,. The effect of the sub- interfaces resulted in a surface-induced perpendicu- stituents on both the pyrazolyl and phosphano frag- lar magnetic anisotropy and enhanced PKR in the near- ments was studied, and the results were interpreted W spectral region. The possibility of optimising the in terms of the varying electronic asymmetry they pro- MO characteristics, by changmg x and the growth para- duce at the metal centre. meters, makes this Pt multilayer important for obtain- ing MO storage media able to work in blue light. Optically Active Bis(oxazoliny1)pyridine (Pybox) Rhodium Complexes: Asymmetric Improvement of Electrical Characteristics of Hydrosilylation of Ketones Pt-Diffused Devices H. NISHNAMA and K. ITOH, J. Synrh. Org. Chem. Bn., B. DENG, c. SHU and H.KUWANO, 3pn. J. Appl. Phys., 1995, 53, (6), 500-508 1995,34, (6A), 2969-2973 Optically active bis(oxazoliny1)pyridine(Pybox) was The elecmcal characteristics of Pt-diffused p'n diodes developed as a chiral N ligand for asymmetric hydro- were improved by reducing Pt-induced adverse effects. silylation of ketones. Pybox reacted with RhCI, in Pt diffusion induces mobile Pt ions to diffuse into the ethanol solution to give a stable RhCl,(Pybox) com- SiO, films and also changes the surface conditions plex, which showed powerful catalytic activity for the near the Si-SiO, interface, thus increasing the leak- hydrosilylation of ketones with diphenylsilane in the age current. The Pt-diffused dipolar devices with a presence of Ag tetrafluoroborate. Acetophenone was (1 00) substrate and a phosphosilicate glass film on reduced to 1-phenylethanol in 91% yield and in 94% SiO, film are effective in both the preservation of elec- ee. Substituents on the oxazoline rings and on the trical stability and reduction of leakage current. pyridine ring were also examined. Spin-Valve Memory Elements Using [{Co- Oxidative Regeneration of Phosphine-Modified Pt/Cu/Ni-Fe-CoJICu]Multilayers Rhodium Hydroformylation Catalysts Y. m,H. SAKAKIMA,M. SATOMI and Y. KAWAWAKE, Tpn. E. V. SLIVINSKII, V. I. KURKIN, M. M. ALI, G. A. KORNEEVA, J. AppI. Phys., 1995, 34, Part 2, (4A), L415-L417 R. A. ARONOVICH, 0. W. PESM, M. A. MORGUUS and W. Development of a new type of magnetoresistivemem- I. SOLOVETSKII, Nejiekhimiya, 1995,35, (2), 159-163 ory using magnetic spin-valve multilayers, where mag- Studies were made of oxidative regeneration of deac- netisation switching of the semi-hard magnetic Copt tivated PPhJRh catalyst during hydroformylation of layer is used for data storage and that of the soft mag- olefins in atmospheric 0,. The results showed that netic NiFeCo layer is used for data readout, is reported. the application of ozonisation, ultrasound and expo- The fabricated memory element was made of a word sure to light of accelerated electrons noticeably inten- line of Au film and a magnetoresistive sense line of sified the regeneration of deactivated catalysts. [ { Co-Pt/Cu/Ni-Fe-Co}/Cu] multilayers.

Platinum Metals Rev., 1995, 39, (4) 185 NEW PATENTS METALS AND ALLOYS Electrode for Electrolysis PERMELEC ELECTRODE LTD. Manufacture of Finely Divided Particles of Japanese Appls. 7162,583 and 7162,585 Silver-PalladiumAlloys An electrode assembly has contacting surfaces coated E. I. DU PONT DE NEMOURS & CO. by Pt group metal or their oxides, thin film forming US. Patent 5,429,657 metal or a corrosion resistant conductive layer. The Finely divided particles of Ag-Pd alloy are manufac- electrode consists of a base material, a coating layer tured by aerosol decomposition of an aqueous solu- of Pt group metal and at least one of Ti, Ta, Nb, etc., tion containing Pd and Ag nitrates. The aerosol is of thickness 10-200 p.The electrodes can withstand heated to above the decomposition temperature of alternating voltage and are assembled on a demount- the Ag and Pd compounds, but below the melting able ftvture having little contact resistance, so are point of the Ag-Pd alloy, to form a densified alloy, fol- stable for long periods. lowed by separation of the Ag-Pd alloy particles. The powders are fully dense with high purity. ELECTRODEPOSITION AND Ultrafine Palladium Alloy Particles SURFACE COATINGS TANAKA KIKINZOKU KOGYO K.K. Japanese Appl. 7/24,3 18 Iridium-Coated Products Ultrafine particles of Ag-Pd alloy are prepared by dis- NIPPON ELECTROPLATING ENGINEERS K.K. solving AgzPd(C20r)zin an aqueous solution con- Japanese Appl. 7134,289 taining polyvinylpyrrolidone(PVP) and irradiated by Ir-coated products, for crucibles or electric contacts, W light in solution. The particles of the Ag-Pd alloy comprise a base of W, Mo, Ta or their alloy, coated contain 50-80 at.% Ag, Ag-Pd alloy with an atomic by an Ir layer. In an example, a W crucible was first ratio of Ag:Pt = 2:1, or Ag-Rh alloy with an atomic coated with which was then coated with in a bath ratio of Ag:Rh 2: 1. the production of ultrafine Pt Ir = In containing 10 g metau Na hexabromoiridium(III), particles of Ag-Rh alloy, AgRh(Cz04),is dissolved 40gll boric acid and 0.02 moll1 disodium maloate, in an aqueous solution containing PVP and NaBH,. at pH 5 and 85"C, and at 0.15 Aldm'. The Ir layer was 8pm thick and was highly adhesive. ELECTROCHEMISTRY Palladium Electroless Plating Solution Palladium Surface Enriched Electrode KOJIMA KAGAKU YAKUHIN K.K. KOBE STEEL LTD. Japanese Appl. 7126,390 Japanese Appl. 7162,549 Ti (alloy) electrode material comprises a layer enriched A Pd electroless plating solution contains 0.00014)).5 by a Pt group element, such as Pd, on its surface moll1 of Pd compounds, 0.0005-8 mom NH, andlor and an oxidised layer formed on the Pt group metal amine compounds, 0.0005-5 moll1 aliphatic mono-, enriched layer. The electrode is used in sea water elec- di- andlor polycarboxylic acids. High purity, stable trolysis and for the production of Cl,. It has high cor- and cracking free Pd plating is obtained with good rosion resistance and high current efficiency. coating and bonding abilities. Hydrogen Peroxide Production Polyimide-Metal Foil Composite Film MITSUBISHI GAS CHEM. CO. INC. OKUNO PHARM. IND.K.K. Japanese Appl. 7170,762 Japanese Awl. 7133,410 A Pd layer 3400A thick is formed by vapour depo- Aqueous H,O, is produced by reacting H, and 0,in sition on one or both sides of an aromatic polyimide the presence of Pt group metal catalyst, preferably a film, electroless plated and electroplated, with Cu Pd, which is chemically modified with at least one ele- for example, to yield a polyimide-metal foil compos- ment selected from Pb, Zn, Ga or Bi, in a reaction ite The method is used for printed circuit boards. medium containinga H,Oz stabiliser, such as aminotri- film. (methylphosphonic acid), 1-hydroxyethylidene- 1,l- The polyimide-metal foil has excellent heat resistance, so high temperature treatment is possible.. diphosphonic acid, ethylenediaminetetra(methy1ene phosphonic acid), or pyrophosphoric acid. No halo- Spherical Electroless Plating Powder gen ions are required in the reaction medium to pro- mote the reaction of H, and 0,. NIPPON CHEM. IND. CO. LTD. Japanese Appl. 711 18,866 Ion Water Generation Spherical core material, such as resin, is coated with BROTHER KOGYO K.K. Japanese Appl. 7151,674 a 0.05-0.3pm thick layer of 7-15 wt.% Ni-P alloy. Pd An ion HzOgenerator is equipped with a pair of spe- ions are electroless plated on the surface of the core cific electrodes for HzO electrolysis. The electrodes material by dispersing complexing agent in the core are made of Ti and are coated with a metal film, prefer- material slurry and in a plating bath, followed by ball ably Pt or Pt-containing alloy, containing a reduced mill grinding. A well dispersed spherical electroless amount of oxide impurities. plating powder, and a conductive material are obtained.

Plarinum Metals Rev., 1995, 39, (4), 186-190 186 APPARATUS AND TECHNIQUE Preparation of Unsaturated Glycol Diester MITSUBISHI CHEM. COW. European Appl. 647,6 11.4 Treatment of Acid Water Unsaturated glycol diesters are prepared by reacting KURITA WATER IND. LTD. Japanese Appl. 7180,473 a conjugated diene with a carboxylic acid and 0, over The treatment of acid HzO(1) containing H20, and a Pd and Te catalyst supported on solid SO,, where surfactant comprises keeping (1) in contact with a Pt 80% of the pore volume has a radius of 5-50 nm, rel- catalyst and with activated C. The method particu- ative to the total volume of pores of radius 1.8-1 0,000 larly treats rinsed drainage released from a semicon- nm. The process can be performed indusmally and ductor manufacturingplant. The Pt catalyst is applied deactivation rates for > 3900 h of 0.42 can be obtained. to the acid region of pH 3 and almost completely decomposes and removes HzO,.The activated C effi- Dehydrogenation of Gas Streams ciently absorbs and removes the surface active agent. HALDORTOPS0EA.S. European Appl. 655,431A The method is used to prepare ultrapure H20fiom H, is removed from a HC-dehydrogenation reaction waste H,O semiconductor rinses. effluent by mixing with an O,-containinggas and reacting over a catalyst containing a noble metal or its alloy Oxygen Recovery from Life Support System in massive form. In an example, Pd and 70%Pd-Ag DORNIER G.m.b.H. German Appl. 4,333,504 alloy catalysts were used as flakes with a size of 16 0, recovery from life support systems uses a low tem- cm'lg metal, and 0.5 g of this catalyst was loaded in perature catalyst, especially RuOniO,, to convert COz a quartz tubular reactor. The process gives complete to CH, and to electrolyse H20.The electrolytic cell removal of H,. may have a KOH electrolyte, one containing HZO, or solid electrolyte; a proton-exchange membrane; Catalyst for Purification of Engine Gases or may be a molten carbonate cell. The recovery occurs CATALER IND. co. LTD. European Appl. 657,204A at 2&200"C. Gas permeation to concentrate CO, uses A catalyst for purification of engine exhaust gases a liquid membrane, or activated charcoal, adsorp- comprises a support of TiO,-A1,0,, ZrO,-Al,O, or tioddesorption with solid amine, etc., as adsorbent. SiO,-Al,O, carrying a N oxide adsorbent which may The process is especially useful for space travel. be alkali metal(s), alkaline earth rnetal(s), etc., and a Pt group metal catalyst, selected from Pt, Pd and Gas Cleaning Apparatus Rh. The catalyst inhibits poisoning from S oxides, FuJlTsu LTD. German Appl. 4,426,081 and N oxides can be purified even during engine oper- Gas cleaning apparatus incorporates rotating catalytic ation in the fuel-lean mode. metal blades of Pt, Pd, Ru or Rh metal catalyst, within a housing where the housing wall incorporates a mag- Exhaust Gas Purification Catalyst net which generates high density plasma. The appa- TOYOTA JIDOSHA K.K. European Appl. 658,370A ratus treats industrial effluent and vehicle exhaust. A catalyst is produced by loading an N oxide adsor- Incoming gas impinges on the blades in the 0,-free bent on a porous support, carbonating the support environment. The combination of catalytic treatment with the adsorbent, which is an alkali metal com- and high density plasma generates synergy between pound, etc., to convert it to carbonate, and loading the cleaning processes; and 0,-rich gases are cleaned. a Pt, Pd or Rh metal catalyst onto the support. NOx can be effectively purified in exhaust gases that contain 0, concentrations at stoichiometry,or higher con- JOINING centrations than needed for oxidising CO and HC. Platinum Material for Brazed Ornaments Catalyst for Exhaust Emission Control TANAKA KLKINZOKU KOGYO K.K. HONDA MOTOR co. LTD. Appl. 9519,048A Japanese Appls. 7141,885-86 World An exhaust emission control catalyst has 8- and Q- Pt brazing material comprises 0.01-1 wt.% of at least phases, and is made of modified AlzO,with an a ratio one of Ti, Zr, Hf and rare earth elements, and bal- of 0.5-95% and a catalytic metal, such as Pt, car- ance pt. It may also contain elements, such as Y, Sm, ried on the modified ALO,. In addition, a catalyst with Eu and Er. The materials are used for ornaments hav- improved NOx cleaning capability is constituted by ing high hardness. using the above catalyst as a catalytic element and alu- minosilicate or CeO,. HETEROGENEOUS CATALYSIS Three-Way Catalyst But-t-ene-l,4-diol Production ALUED-SIGNAL INC. World Appl. 9519,687A BASF A.G. European Appl. 646,5 62A CO, HC and NOx are removed from the exhaust gases But-2-ene-l,4-diol is produced by selective hydro- of lean burn diesel and other engines, containing 0, genation of but-2-yne-l,4-diol in aqueous solution in excess of the stoichiometric amount needed for on a Pd-containing solid-bed catalyst, which is doped complete combustion, by contact with a Pt andor Pd with Pb or Cd. The catalyst is obtained by successive catalyst, preferably Pt, supported on A120,,CeO, and vapour-phase deposition or sputtering of Pd, and Ba sulphate, Sic, ZrO,, SiO,, TiOz, etc. The cata- Pb or Cd, onto a metal wire mesh or metal foil sup- lyst has been treated in an 0,-inert gas mixture, option- port, then formed in air at high temperature. There ally including steam at 2 400°C, to give NOx reduc- is minimal by-product formation. tion at a predetermined temperature window.

Platinum Metals Rev., 1995, 39, (4) 187 Purification Catalyst for Lean Mixture Exhausts Catalyst for Purification of Exhaust Gases KEMIRA OY. World Appl. 95110,356A NISSAN MOTOR CO. LTD. Japanese Appl. 7116,466 A catalyst comprises a body with flow through con- A purification catalyst is composed of 0.1-10 gll Pt duits for exhaust gas, a high surface area support of or Pd, 1-30 gll K, Cs, Sr or Ba oxides, 1-50 gll Co an A120, plus La oxide mixture on the surface of the or Mn oxides, Ce oxide and activated Al,O,. HC, CO body, with active catalytic Pt and Pd substances on and NOx in exhaust gases are removed efficiently even the support. The catalyst purifies exhaust gases from under 0,-deficient and HC-rich atmospheres. lean mixture engines, particularly diesel engines, containing SO,. Hydrocarbons and CO in the exhaust Purification Catalyst Production gases are converted to CO, and H,O. Light-off tem- MATSUDA K.K. Japanese Appl. 711 6,469 peratures are lower and the catalyst has a long life. A metal containing silicate and aqueous Rh solution, such as Rh nitrate, is added to a Pt solution, such as Pentafluoropropane Production a Pt amine, and to an Ir solution, such as IrCl,, to DAIKlN KOGYO K.K. WorldAppl. 95113,256A form a slurry which is filtered to become the NOx 1,1,1,3,3-Pentafluoropropane(1) is prepared in high purification catalyst. A metal containing silicate, sup- yield and selectivity by reducing 3-chloro- 1, 1 , 1,3,3- porting highly dispersed Pt, Ir and Rh, is obtained. pentafluoropropane with H, in the vapour phase in the presence of 0.05-10 wt.% of Pd, Pt andlor Rh Preparation of High Purity Terephthalic Acid catalyst, supported on C, A120,, SiO, gel, TiO, and/or MITSUBISHI KASEI COW. Japanese Appl, 7/17,903 ZrO,. The product is a substitute for CFCs and The preparation of high purity terephthalic acid (1) HCFCs for use as a coolant, foaming agent, etc. comprises dissolving crude (l), made by a liquid phase oxidation ofp-xylene in H,O at 22O-32O0C, and then Reduction of Nitric Oxide contacting with a Pt group metal catalyst, such as W. R. GRACE & CO. World Appl. 95115,208A PdC. This is followed by cooling to crystallise a first NO is reduced by organics in the presence of 0, by crop of (l), and separation from the mother liquor, passage over a catalyst comprising 0.2-10 wt.% of a with further cooling to recover a second crop. The Pt group metal catalyst, such as Rh and/or especially recovery yield is improved by the second crop. About Pt, on a stable dealuminated Y zeolite, from which 90-99.5% of (1) is crystallised in high purity. non-hmework Al,O, was removed. The zeolite kame- work has molar ratio SiO,: A1,0, > 10. The catalyst Diesel Engine Exhaust Purification Catalyst has improved NO reduction ability and more resis- icr K.K. Japanese Appl. 7124,260 tance to any reduction in activity caused by H,O or SO,. A catalyst consists of a three dimensional structure coated with a catalyst composite of Pt and/or Pd loaded Preparation of Hydroxylamine Derivatives inorganic oxide powder (1) and another inorganic DSM N.V. World Appl. 9511 6,667A oxide powder (2). Powder (2) forms 0.25-25 g/l of N-Alkyl-N,O-diacetyl hydroxylamine is prepared in the structure. Powder (1) is loaded with 5-50 wt.% a simple one-step reaction by catalytic reduction of Pt andlor Pd, and a metal oxide selected from W, Sb, the corresponding nitroalkane, preferably nitro- Mo, Ni, B, Mn, Fe, Bi, Co, Zn or alkaline earth metal. methane, in the presence of acetic anhydride over The catalyst is used to remove C and S-containing Pt/A1,0, catalyst. The reduction is carried out at particulates from diesel engine exhaust. The forma- 20-100°C and 1-9 MPa. The acylating agent, acetic tion of sulphate is suppressed. anhydride, separates the products. Exhaust Gas Purification Catalyst High Purity Benzene Production NE. CHEMCAT K.K. Japanese Appl. 713 1,884 CHEVRONRES. &TECHN. CO. Us. Patent 5,401,365 Ir and an alkaline earth metal, such as Ca, Sr and Ba, Benzene is produced in high purity from olefin-con- are supported by metal carbide, such as Sic, or a metal taining aromatic feed by distillation to remove high nitride, which is moulded or coated on a refractory boilers (l), followed by extractive distillation (2). Also substrate, and contacted with an exhaust gas con- claimed is a process for contacting a HC feedstream taining HC, NOx and excess 0, to reduce HC and with a non-acidic Pa-type zeolite catalyst. The pre- purify it. NOx is removed efficiently in the presence of distillation step (1) prevents detrimental dimerisation 0, and under a high space velocity using the catalyst. reactions in (2), thus removing the need for hydrogenation before or after (2), or clay after-treatment. Hydrosilylation Catalyst DOW CORNING TORAY SILICONE Tertiary Butyl Alcohol Preparation Japanese Appl. 714 1,678 TEXACO CHEM. INC. US. Patent 5,401,889 A hydrosilylation catalyst with average particle size Tertiary butyl alcohol (1) is prepared from a charge 0.1-10 pm comprises a Pt catalyst, containing 0.01-5 stock solution containing 5-30 wt.% tertiary butyl wt.% Pt metal, and a polycarbonate resin with a glass hydroperoxide by continuous contact with a pelleted transition point of 50-200°C. The catalyst is useful hydroperoxide decomposition catalyst Pd-Au/Al,O, as a curing catalyst for organopolysiloxane composi- in liquid phase agitation, at 25-25OUC, space veloc- tions. It does not show catalytic activity at ordinary ity of 0.5-2 vol. of charge stockkol. catalystlh and temperature, so this composition has good storage 0-1,000 psig pressure. The process gives improved stability, and the composition is easily cured by heat- conversion rate and selectivity to (1). ing, even after a long period of storage.

Platinum Metals Rev., 1995, 39, (4) 188 Removal of Organic Chlorine Compounds A Noble Metal Catalyst SUMITOMO METAL MINING CO. KUNMING INST. NOBLE METALS CHINESE NON. Japanese Appl. 7147,270 Chinese Appl. 1,087,031 A catalyst carrier, for removing organic chlorine com- A Pt group metal catalyst for purifylng waste gas from pounds in air, is prepared by dropping an alkali solu- I.C.E. contains one of Pt, Pd, Rh or Ru (0.06-0.3 tion into an aqueous solution of 10-20 wt.% of a Zr wt.%) as the active component. The carrier is in the mineral acid salt to react them, ageing to give Zr form of a ball or honeycomb made of China clay hydrate and calcining at 500-600°C. The carrier is and industrial Al oxide. A quick dipping method is impregnated with Pt containing solution to give 0.3-5 used to add the active component to the carrier. The wt.% of Pt, followed by further calcining. catalyst gives high purification and a long service life. Metal Support for Catalysts TANAKA IUKINZOKU KOGYO K.K. HOMOGENEOUS CATALYSIS Japanese Awl. 7180,327 A metal support for a catalyst used for high temper- Preparation of N-Vinyl Compounds ature gas purification, such as in gas turbine engines, BASF A.G. European Appl. 646,571A has a coating of Pt, Pd or Pt-Pd alloy film. The sup- The preparation of an N-vinyl compound from NH port has good resistance to heating and oxidation at compounds uses acetylene at 50-250°C and 1-30 bar > 1000°C.In an example, plates of stainless steel and in the presence of a Pt group metal compound cata- Pt were immersed in an electrolytic cell of aqueous lyst, such as F'dCI,, OsCI,, Ru(acac),, RuCI,, etc. The chloroplatinate solution to form a Pt layer on the steel. process gives an improved space-time yield and bet- A porous Al,O, layer and a further Pt layer were added. ter control of the conversion of the acetylene. The N- vinyl compounds can be used as monomers, giving Hydrocarbon Absorbing Catalyst polymers for clarifying liquids, detergents, etc. NISSAN MOTOR CO. LTD. Japanese Awl. 71124,468 Hydrocarbon absorbent comprises a monolithic car- Hydroxy-Carbonylationof Butadiene rier, coated with an aqueous slurry containing zeolite, RHONE POULENC CHIM. European Appl. 648,731A such as mordenite, USY, p-zeolite, etc., and further The hydroxy-carbonylation of butadiene andor deriv- coated with active CeO, and/or Al,O, slurry contain- atives was produced by reaction with CO and H,O in ing at least one of Pt, I'd and Rh. The zeolite has micro- the presence of a Pd catalyst, such as PdCl,, Pd acetate, pores to assist diffusion of gas to the absorption sites. etc., which is soluble in the reaction medium. The 51.7% HC was absorbed in 125 s of cold start. reaction is performed in the presence of crotyl chloride ( 2 2 molelmole of Pd) as the promoter. Reactor for Removing Carbon Monoxide Production Higher Vinyl Esters DAIMLER-BENZ A.G. German Appl. 4,334,981 of A reactor for catalytic removal of CO in H,-rich gas UNION CARBIDE CHEM. & PLAST. TECHNOL. is coated with a selective CO-oxidation catalyst con- European Appl. 648,734A taining Pt group metal catalysts, such as Pt/Al20,, Homogeneous liquid phase vinyl carboxylates are pro- Ru/Al,O, or Ptheolite. The structure of the reactor duced by reacting ethylene and carboxylic acid, prefer- creates turbulent flow and heat transport. The reac- ably butyric, crotonic, benzoic, etc., using a Pd(I1) tor can be used in conjunction with a fuel cell and catalyst formed in situ, Cu oxidant and Li promoter. prevents steep temperature gradients. Higher yields, - 69%, of vinyl esters are obtained. Exhaust Gas Purification Catalyst Low Temperature Carbonylation MAZDA MOTOR COW. German App1. 4,435,074 IMPERIAL CHEM. IND. P.L.C. World Awl. 95115,938A A catalyst component for exhaust gas purification Low temperature carbonylation of acetylenically unsat- comprises a mixture of a metallosilicate having at least urated compounds with CO in the presence of an one active Pt group metal, such as tetra valent Pt and allenically unsaturated compound, uses a catalyst sys- Ir, mixed with Al,O, and/or CeO,. Also claimed is the tem formed from a Pd compound, such as Pd acetate, production of a honeycomb catalyst comprising the etc., a protonic acid and an organic phosphine. The component, which is wash-coated or aged, or vice catalyst tolerates allenically unsaturated compounds versa. The addition of A120,and/or CeO,, and the use and carbonylates them, e.g. butyne, pentyne, cyclo- of Pt andor Ir in the +4 oxidation state shifts the peak hexylethyne from feedstocks obtained from cracking temperature of NOx reduction to higher values. oil fractions. A Palladium Catalyst Stereoselective Synthesis of Carbohydrates AS. SIBE. CATALYSIS INST. Russian Patent 1,420,7 14 SCRIPPS RES. INST. World Appl. 95116,049 A catalyst for the production of dimethylvinylcarbinol Carbohydrate is prepared by stereoselectively convert- is prepared by dissolving Pd chloride in a boiling Na ing an alkene to an aldol intermediate by an Os- molybdate solution in molar ratio Mo:Pd of 1-1.5: 1, catalysed asymmetric dihydroxylation reaction, then before reducing with H, to form Pd metal, and mix- stereoselectively elongating the aldol intermediate with ing with an inorganic carrier. The catalyst gives a nucleophilic donor using an aldolase-catalysed aldol improved activity and productivity without significant addition reaction. A rapid synthesis of ketose sugars is reduction in selectivity. achieved by a minimal numbers of steps.

Platinum Metals Rev., 1995, 39, (4) 189 Method for Producing Allylic Alcohols Structure for Mounting Electronic Parts UNIV. IOWA STATE RES. FOUND. INC. KYOCERA COW. Japanese Appl. 7140,569 US.Patent 5,401,888 Electronic parts are mounted on a ceramic baseplate Preparation of allylic alcohols in good yields com- by soldering the electrodes of the electronic parts onto prises a Pd catalysed cross-coupling of vinylic epox- the wiring layer on the ceramic baseplate. The wiring ides and aryl halide, vinylic halide or vinylic triflates. layer comprises a lower layer of Pd and an upper layer Pd (11) catalysts, such as PdCl,, Pd(OAc)>,PdBrz, of Ni or Cu. The Pd metallic layer is laminated. The Pd(CN),, etc., are used. The Pd(0) catalyst is Pd(dba), connection is reliable against thermal changes and or Pd(PPh,),. The organic base is a 6-20C tri- parts can be mounted to a high density. alkylamine or dicycloalkyl(alky1)amine. The reaction is performed at 60-120°C for 5-50h. Overwritable Recording Medium TOSOH COW. Japanese Appl. 7/44,9 15 Hydrodehalogenation of Halogenated Benzenes A photomagnetic recording medium for high density BAYER A.G. German Appl. 4,334,792 recording or overwriting comprises a substrate, record- Hydrodehalogenationof halogenated benzenes com- ing film of artificial lattice film made of laminations prises reacting with H2at 100-250°C in the pres- of a layer comprised of at least one element selected ence of a catalyst prepared by depositing Pd andlor from Fe, Co or Ni and a layer based on Pt andlor Pd, Pt salts, and optionally Cu salts, on an A120,or TiO, and at least one layer of a rare earth transition metal support. The process produces useful lower halo-ben- alloy layer (1). The artificial lattice film is reverse sput- zenes, such as o-dichlorobenzene, monochloroben- tered, and (1) is formed on it. zene andlor benzene, from higher chlorobenzenesand pdichlorobenzene. Good yields and selectivity, with- Multilayer Interconnection Board out forming cyclohexane derivatives, are achieved. IBIDEN CO. LTD. Japanese Appl. 711 06,758 An additive process for manufacturingmultilayer inter- FUEL CELLS connection board maintains the density of Pd ions in the liquid that is used during the Pd catalyst nucleus acti- Fuel Battery Electric System vation process at 5 1.2 ppm. An insulated adhesive layer is formed on a substrate; followed by a conductive layer, NGK INSULATORS LTD. Japanese Appl. 7157,758 and then through hole formation. A fuel battery power generation system incorporates a gas isolated membrane made up of Pd alloy, con- Bump Electrode Formation Method taining dissolved H, gas, which covers the support TANAKA DENSHI KOGYO K.K. body. The fuel gas is refined using the H2 gas isola- Japanese Appl. 71122,563 tor.The support body carries a negative electrode. The method uses Pd wire, t 99.9% pure, which is The system increases the density of the fuel gas. It has elongated by 2-6%. The wire is shaped as a thin line improved electric power efficiency and removes CO, and is inserted into a capillary tube. A ball is produced which poisons the electrode. under Ar, and adheres to the top surface of an A1 wiring of a semiconductor chip. If the capillary is CHEMICAL TECHNOLOGY removed, the wire gets disconnected at a predetermined location, and a bump electrode is formed. HexahydroxoplatinicAcid Preparation TANAKA KIKINZOKU KOGYO K.K. MEDICAL USES Japanese Appl. 7/97,22 1 Preparation of H,Pt(OH), comprises neutralising Na Dental Alloy hexahydroxoplatinateby ion exchange through con- JENERlCiPENTRON INC. US. Patent 5,423,680 tact with an inorganic acid via a cation exchange mem- The dental alloy, free of Pd, Ga and Cu, comprises brane.The H,Pt(OH), obtained can be used as a raw (by wt. %): (a) 40-80 Au; (b) 5-50 thermal-expan- material for catalysts and as an intermediate for Pt sion adjuster, selected from Pt, Ag, Nb and Ta; (c) compounds. The waste liquor contains organic no 2-10 strengthener and oxide-former; (d) S 1.5 grain compounds, and can be treated easily at low costs. refiner selected from Ir, Ru, Rh, Re and Co; and (e) 0.25 deoxidiser. The ailoy is compatible with high- ELECTRICAL AND ELECTRONIC TCE dental porcelains and composites. ENGINEERING Yellow Dental Alloy A Hard Disc Recording Medium HERAEuS KULZER G.m.b.H. German Am/. 4,429,728 HE-~-PACW co, European A@/. 65 1,380A A Yellow contains Plus Pt group metals and base metals, and has the following com- A hard disc with textured surface having reduced sta- position (in wt.%): 80-95 Au, 5-20 Pt, 0.01-0.3 Rh, tic and dynamic friction is formed by applying a Ni- 0-0.1 Ir, 0.5-2.5 Zn and 0.01-0.5 Mn. The alloy is Pt layer on a metal substrate, than polishing to sur- used 10 manufacture ~uki-sectionbridgework. face rouhessof < 2 nm RMs, then sputtering on a metal layer having RMS surface roughness 1.O&O nm. Low flying height between the recording head The New Patents abstracts have been prepared from and the spinning recording media is obtained. material published by Denvent Publication Limited.

Natinum Metals Rev., 1995, 39, (4) 190 AUTHOR INDEX TO VOLUME 39

Page Page Page Page Abbot, D. 183 Ben-Jacob, E. 137 Chen, J.F. 80 Duff, R. R. 140 Abrams, M. J. 14 Bergamini, F. 140 Chen,L. 41 Duncan, P. N. 112 Abys, J. A. 138 Bertani, R. 134 Chen, L. J. 80 Durussel, P. 37 Achiba, Y. 81 Be* v. 85 Chen,Q. 41,137 Dux, R. 136 Adachi, H. 32 Bertolini. J. C. 42 Chen.2. 136.184 Duxstad, K. J. 180 Adams, J. B. 37 Be&,T. 183 Chemov, S. F. 41 D’Agostino, It. 84 Aghossou, F. 87 Besson, M. 159 Chevalier, B. 38 Ahmed, 2. 43 Bhanaga, B. M. 62 Chikahisa, T. 85 Ebert, H. 38 Aka, K.4 139 Bilitewski, U. 41 Cho, C. S. 184 Eehigoya, J. 83 Aitani, A. M. 27 Blake, A. J. 82 (30,J.-J. 82 Efremenko, I. G. 42 Aleandd, L. E. 180 Block, J. H. 80 Choy, J. H. 134 Eisenberg, R. 181 Ali, M. M. 185 Boelrijk, A. E. M. 44 Chu, V. 86 Elefant, D. 38 Al~n~o-Vt~~te,N. 39 Biinnemann, H. 42,180 Claver, C. 87 El-Shafei, A. A. 181 Alper, H. 86,140 Boonekamp, E. P. 80 CobG. M. 135 Enoki, A. 83 Al-Shmf, H. N. 64 Bosrh, P. 85 Colell, H. 39 Espeel, P. H. 42 Amado, M. M. 38 Boukamp,B.A. 133 Conole, G. 87 Epsalik, A. 44 Amano, M. 87 Bourdelande, J. L. 83 Coote, S. J. 86 Esteruelas, M. A. 140 Amezawa, K. 83 Boumt, E. D. 180 Co#ington, I. E. 67.78 btourneau, J. 38 An, L. D. 139 Bouwmeester, Coupland, D. R. 98 Evens, J. M. 98 PO, M: 84 H. J. M. 133 Couzens, G. 112 Eyert, V. 134 Antoneh, E. 140 Bozon-Verd-, F. 184 Cowley, A. J. 116 Ezhova, N. N. 185 Antonova, T. N. 183 Bradley, J. 41 Cmgle, J. 37 Autos, G. J. 27 Braga, M. E. 38 Creyghton, E. J. 183 Fabrizio, M. 181 Aoki, K. 185 Brinlunann, R 42 Crozet, M. 136 Fendler, J. R. 180 Arata, K. 85,138 Bronger, W. 39 C®i, E. 137 Fen& Q. 135 Arblaster, J. W. 164 Brook, R. J. 134 Cummings, S. D. 181 Feschotte, P. 37 Arenshtam, A. 137 Brook-, H. C. 107 Fiechter, S. 39 Arimitsu, S. 87 Brown, J. M. 62 Da Suva, Fierro, J. L. G. 84 Armor, J. N. 133 Brown, S. M. 87 M. de F. C. G. 134 Fiseher, J. 181 Aronovich, R. A. 185 Bruce, R. 45 Das, M. L. 40 Flachbart, K. 88 Asayama, E. 81 Bruk, L. G. 139 Date, M. 37 Fhagan, T. B. 133 Ashokkumar,M. 40 Buckley, T. 39 Davidson, J. L. 41 Fokkink, L. G. J. 80 Ashton, Bulple, J. 132 Davies, S. G. 62 Font, J. 83 S. V. 13,32, 132, 159 Bulsman, G. J. H. 140 Davis, M. E. 62 Fornasiero, P. 85 AuaeUo, 0. 64 Burch, R 84,138 Dawson, G. J. 86 Fowler, J. B. 72 Auffennann, G. 39 Burgers, M. H. W. 183 De Boer, F. R. 38 Fox, M. A. 42 Aye, K. T. 136 Burggraaf,A. J. 133 De Ci,A. 181 Fracassi, F. 84 Aymerich, X. 182 BurgstaUer, A. 38 De Cola, L. 136 Freund, H.J. 183 Bustin, D. 137 De Peuter, G. 42 Fricker, S. P. 150, 179 Baak, M. 136 DeganeUo, G. 139 Fmt. J. C. 126. 171 Baiker, A. 138,183 Cabrera, A. L. 80,133 Del Angel, G. 85 Fu, riG. 88 Baker, M. J. 87 Cabrera, C. R. 82 Delarue, E. 133 Fujita, T. 32 Bd,V. 136 Cacucci, A. 84 Delcourt, M. 0. 133 Fukuda, M. 83 Bamwenda, G. R 184 Cade, N. A. 141 Delmas, H. 62 Fukushima, K. 87 Barbi, G. B. 181 Cai, H. 42 Demazeau, G. 134, 135 Fukuyo, E. 184 Barbier, J. 85 Candela, G. A. 137 Deng, B. 185 Funatsu, K. 135 Bardin, M. 84 Cant, N. W. 183 Dew, F- 139 Barnard, C. F. J. 63 Cao, G. Z. 133 Deshpande, R. M. 62 Gallemt, P. 159 Barniol, N. 182 Carley, A. F. 41 Desu, S. B. 45, 141 Gat’vita, V. V. 88 Barton, J. K. 84 Carpita, A. 139 Di Monte, R. 85 Gam, K. S. 45 Bashilov, V. V. 38 Cd,B. T. 41 Diesner, K. 39 Gaudhi, H. S. 84.85 Battle, P. D. 38 Cnsella, I. G. 182 Dimitrov, D. A. 129 Gao, C. 37 Bat’ko, I. 88 CasMo, A. 41 Do, Y. 134 Gao, Y. 40 Becker, E. R. 171 CastiU6n, S. 87 Dobreva, E. D. 137 G&R 159 Bednon, J. G. 32 Cavinato, G. 86 Doherty, A. M. 85 Garnett, J. L. 140 Beller, M. 183 Cazorla-Amor6s, D. 84 Doherty, A. P. 39 Gasteiier, H. A. 82 Bellina, F. 139 Cerveny, L. 184 Dong, s. 81, 181 Gas’kov, A. M. 37 Bellur, K. R. 64 Chabutkina, E. M. 183 hnb,A. 135 Gautheron, B. 37 Belper, P. 136 Chan, T. H. 88 Dwglas, p. 183 Gehlen, M. 39 Belyaev, V. D. 88 Chatani, N. 141 Doyle, M.P. 44 Ghash, K. 81 Belykh, L. B. 19 Chaudhari, R. V. 62 Dub s. 83 Giger, T. 138 Bennett, S. 87 Chen, C. S. 133 Duca, D. 139 Giles, M. F. 87 Bensalem, A. 184 Chen, C.-H. 39 Diimpelmann,R. 183 Giordano, G. 44

Platinum Metah Rev., 1995,39, (4), 191-195 191 Page Page Page Page Gladii, S. L. 43 Hirai, T. 83 Kaliaguine, S. 45 Kramer, H. 85 Gladun, C. 38 Hodgson, D. R. 137 Kamatani, A. 141 Kraus, G. A. 139 Gleiter, H. 80 Hoffman, M. Z. 40 Kamegaya, Y. 135 Krausz, E. 40 Golberg, D. I26 Holmlin, R. E. 84 Kamer, P. C. J. 86, 140 Krishnan, R. 185 Gomez, R. 85 Holtz, R. L. 137 Kameyama, K. 39 Krhlas, K. 81 Gontazh, R. 88 Hong, C. I82 Kandasamy, K. 133 Kruidhof, H. 133 Gonzalez, R D. 138 Hongo, S. 141 Kang, B.-C. 183 Kubasheva, A. Zb. 42 Godez-Marcos, Horikawa, H. 126 Kang, K. H. 45 Kudo. A. 40, 135 M. P. 41 Hosseini, M. W. 181 Kang, W. P. 41 Kudkk, E. J. 138 GonzPez-Velasco, HSU,C.-M. 138 Kanoh, H. 135 Kudryavtsev, Yu. V. 88 J. R. 41 Huang, T. S. 88 Kanteeva, N. I. 180 Kiibler, J. 134 Gorelov, V. P. 88 Huang, T.-C. 183 Karasik, A. A. 43 Kiihlein, K. 183 Gori, R. 139 Hubbard, C. P. 84 Karsanov, I. V. 79 Kulmala, A. 182 Goto, S. 139 Hughes, H. P. 182 KaSpar, J. 85 Kulmala, S. 182 Gotoh, K. 43 Hutchison, J. E. 39 Kato, H. 45 Kumada, T. 37 Gould, R. D. 45 Kato, K. 141 Kumobayashi, H. 87 Grandberg, K. I. 39 Ibata, T. 87 Kawataka, F. 134 Kunitskii, A. A. 183 Grandjean, B. P. A. 45 Ibbotson, A. 41 Kawawake, Y. 185 Kunkely, H. 182 Graziani, M. 85 Ichikawa, M. 139 Keeling, A. G. 45 Kuriyama, Y. 141 Griffiths, S. P. 41 Igarashi, M. 83 Keene, F. R. 181 Kurkin, V. I. 185 Grigoryan, E. A. 40 Iglesia, E. 43 Kelly, D. M. 39 Kurachkin, I. N. 41 Grimmeiss, H. G. 134 Iizuka, N. 141 Kelly, J. J. 80 Kuwano, H. 185 Grivas, S. 140 Ikemoto, I. 81 Kelly, J. M. 136 Kuwano, R. 140 Grotzschel, R. 38 Ikonen, M. 82 Keppler, B. K. 45 Kuz’mina, L. G. 39 Gruzdkov, Y. A. 40 Imamura, H. 81 Kerns, D. V. 41 Gudaviciuu, L. 68 Imamura, T. 135 Kessler, M. 87 Labeau, M. 37 Guerrero-Ruiz, A. 84 Inaguma, Y. 180 Khairullina, R. Z. 43 Laine, R. M. 86 Guez, D. 82 Indolese, A. F. 87 Khannanov, N. K. 40 Landsman, D. A. 165 Guo, J. 85 Inoue, T. 85 Kharitonov, V. G. 43 Lange, H. 38 Gurbuz, Y. 41 Irie, Y. 185 Khil Shin, H. 85 Langer, S. H. 135 Gurunathan, K. 83 Ishida, S. 37 Kibel, M. H. 45 Larock, R. C. 139 G~ti61~~-Ortiz, Ishii, Y. 139,184 Kido, H. 135 Lastovyak, Ya. V. 43 J. I. 41 Ishikawa, M. 133 Kikuchi, K. 81 LeCorre-Frisch, A. I34 G~tiCrre~-OrtiZ, Ito, M. 82 Kim, G.4. 133 Lee, c. w. 140 M. A. 41 Ito, s. 83 Kim, H.-J. 134 Lee, J. 135 Ito, Y. 83, 140 Kim, S. H. 38 Lee, LH. 134 Haapakka, K. 182 Itoh, K. 185 Kim, Y.4. 45 Lee, P.-Y. 138 Hagen, W. R. 45 Itoh, M. I80 Kimura, A. 135 Lee, S.-J. 88 Hahn, P. 139 Itoh, Y. 185 Kimura, M. 184 Lee, S.-M. 133 Hakanen, A. 182 Ivanov, E. 38 Kincaid, J. R. 136 Leech, P. W. 45 Haller, E. E. I80 Ivey, D. G. 45 King, D. A. 182 Lees, A. J. 136 Hanaoka, T. 43 Iwamoto, M. 85 King, R. A. 141 Lerner, B. A. 41 Hao, L. 180 Iwasawa, Y. 85 Kingon, A. I. 64 Levintova, T. D. 184 Hapiot, F. 87 Iyoda, M. 81 Kirsch-de Mesmaeker, Levy, M. 85 Ham, K. 135 Izumi, Y. 139 A. 136 Lewis. Hards, G. A. 9, 160 Kitagawa, J. 133 F. A. 29.75, 127, 133 Hartley, J. P. 98 Jacobs, P. A. 42 Kitakami, 0. 141 Li, F. 181 Harvey, P. D. 136 Jacquet, L. 136 Kitani, A. 83 Li, G.-F. 18 Hasen, J. 80 Jansen, J. C. 183 Kitayama, K. 184 Li, H. 138, 182 Hashioto, H. 32 Jayaraman, V. 136 Kittel, M. U. 40 Li, Q. 136 Hassan, A. K. 45 Jia, Shichong, 167 Klootwijk, A. 140 Li, T. K. 141 Havela, L. 38 Jian, P. 45 Kluson, P. 184 Lichtenberg, F. 32 Hawker, P. N. 2 Jiang, X. 82 Knecht, A. 134 Lihn, C. J. 80 Hayashi, T. 184 Jimenez, J. R. 182 Knight, G. 45 Lin, H.-M. 138 Haynes, A. 134 Jin, 2. 136 Kobayashi, H. 83, 135 Lin, L. 42 He, C. 18 Johnson, B. F. G. 82 Kobayashi, T. 138 Lin, P. 184 Heinrich, A. 38 Johnson, D. R. 85 Kokkinidis, G. 82 Lin, R. Y. 136 Heinz, T. 138,183 Johnston, P. 41 Kolyadko, E. A. 39 Lin, X. W. 180 HeUer, A. 137 Jones, D. J. 180 Komatsubara, T. 37 Lin, Y. S. 136 Henrion, W. 38,39 Jug, D.-Y. 135 Konno, M. 85 Linares-Solano, A. 84 Hetrick, R. E. 40 Juzikis, P. 40,68 Kornberg, B. E. 85 Lindstriim, S. 140 Hibino, T. 137 Korneeva, G. A. 185 Liotta, L. F. 139 Hidai, M. 139.184 Kadija, I. V. 138 Korovina, S. P. 183 Lipponer, K.4. 45 Higbthwer, T. R. 139 Kaes, C. 181 Koshel’, G. N. 183 Lirkov, A. L. 137 Hino, M. 85,138 Kaga, H. 43 Kotov, N. A. 180 Listovnichiy, V. Ye. 174 Hintermann, L. 185 Kakiuchi, F. 141 Kozitsyna, N. Yu. 180 Liu, A.-M. 139

Platinum Metals Rev., 1995, 39, (4) 192 Page Page Page Page Liu, C.-L. 37 Mengoli, G. 181 Nikam, S. S. 85 Perry, R. J. 43 Liu, G.-B. 86 Menon, L. 81 Ning, Y. 19 Perutz, R. N. 111 Liu, J. 41 Meriani, S. 85 Nishimura, J. 83 Pesin, 0. Yu. 185 Liu, W. 37.81 Me%&, 8. 137 Nishiyama, H. I85 Petit, M. 84 Liu, Y. 81 Meyer, T. J. 135 Nihizaki, S. 32 Petrov, E. S. 86 Loader, P. K. 84, 138 Michelin, R. A. 134 Nohira, T. 83 Petrovskii, P. V. 38 Loboda-Cackovic, J. 80 Miegge, P. 42 Noskov, Yu. G. 86 Pettersson, H. 134 Loginova, I. V. 79 Mikd’shina, V. V. 43 Novikov, Yu. N. 82 Petyukh, V. M. 174

Loheac, P. 84 Milli, E. 181 Nfvlt, M. 185 Pfaltz. A. ~~138, 183 Long, M. A. 140 Mills, A. 44 Pindeva, L. I. 137 Lopez-Agudo, A. 84 Minder, B. 183 Obara, M. 141 Pinto, R. P. 38 Lorkovic, I. M. 140 Minowa, T. 83 Ober, K. 85 Pitschke, W. 38 Lu, F. 41 Misumi, Y. 139 Obuchi, A. 184 Plichon, V. 84 Lu, s. 39 Mitamura, T. 135 Oda, K. 37 Podlovchenko, B. I. 39 Lukey, C. A. 140 Miyai, Y. I35 Ogata, A. 184 Pombeiro, A. J. L. 134 Miyake, T. 87 Ogawa, Y. 81 Ponomarev, G. V. 41 Mackenzie, R. A. D. 141 Mizobe, Y. 184 Ohara, T. J. 54 Poon, S. J. 38 Mackovl, S. 133 Mizukami, T. 44 Ohkawauchi, H. 82 Postlethwaite, T. A. 39 Madon, R. J. 43 Mizuno, F. 83 Ohshima, K.4. I33 Potgieter, J. H. 107 Maeno, Y. 32 Mizuno, K. 184 Ohta, T. 87 Potter, R. J. 173 Maggini, M. 135 Moiseev, A. I. 79 Oi, J. 184 Poulios, I. 82 Maier, J. 134 Moiseev, I. I. 43. 180 Okada, Y. 83 Power, D. C. 117 Maisano, J. J. 138 Monteil, F. 140 Okaji, M. 45 Prato, M. 135 Maitlis, P. M. 134 Morale, E. 133 Okino, F, 134 Pratt, A. S. 32 Makhlouf, S. A. 38 Morale-Leal, E. 80 Olivh, M. 140 Prokes, K. 38 Makhmotov, E. S. 43 Morgulii, M. A. 185 Ollivier, J. 86 Prosser, V. 185 Malashkevich, A. V. 139 Morii, Y. 180 Onoue, S. 39 Provenzano, V. 137 Malik, S. K. 81 Morinaga, K. 81 hi,K. 135 Prunier, M. L. 65 Mallat, T. 138, 183 Morneau, A. 82 Orejin, A. 87 Puddephatt, R. J. 180 Mamedyarova, I. A. 39 Morris, G. E. 134 Orij, E. N. 86 Purwanto, A. 38 Manduchi, C. 181 Morris, R. H. 135 Onto, K. 43 Punvoko, A. A. 136 Manivannan, A. 82 Morrissey, R. J. 182 Oro, L. A. 140 Manninger, I. 183 Mortreux, A. 87 Orpen, A. G. 87 Qian, Y. 184 Madcot, P. 85 Moss, J. R. 33 Oshima, R. 180 Qin, Z.-C. 81 Markovif, N.M. 82 Mostafavi, M. 133 Oto, K. 37 Qiu, J.-Q. 139 Markovitsi, D. 82 Mousa, M. S. 80 Otsuka, K. 126 Quagliotto, M. G. 181 Marquh, G. 83 Mozzon, M. 134 Otto, K. 84 Martin, M. E. 140 Miiller, T. J. J. 87, 141 Ovchinnikov, A. N. 41 Raerinne, P. I82 Martinez, J. 141 Mumtaz, K. 83 Rajendran, S. 88 Maruszewski, K. 136 Murai, S. 141 Pa&, 2. 183 Rajumon, M. K. 41 Maruthamuthu, P. 83 Murakami, Y. 39.82 Piissler, R. 134 Ralph, T. R. 9 Marvaud, V. 82 Murakami, Y. 126 Pakala, M. 136 Ramakrishnan, S. 81 Masdeu, A. M. 87 Murase, K. 37 Pakkanen, T. A. 39 Ranga Rao, G. 85 Mas6, J. 182 Murata, T. 184 Pakkanen, T. T. 39 Rao, N. N. 83 Massara, R. 37 Muravama T. 85 Pan, W. 45 Rar, A. 37 Massardier, J. 42 Murray, R:W. 39 PaneUa, F. 140 Rasinkangas, M. 39 Mataka, S. 86 Musakova, E. Yu. 43 Papenmeier, D. M. 84 Raub, Ch. J. 40 Matar, S. F. 134 Mutoh, H. 87 Papkovsky, D. B. 41 Rebizant, J. 38 Matsuhara, T. 44 Papoutsis, A. 82 Rdik,J. 44 Matsuda, I. I40 Naidoo, M. N. 137 Parera, J. M. 27 Reeves, G. K. 45 Matsumoto, H. I85 Nakabayashi, M. 82, 136 Park, J. T. 82 Regnault, D. I33 Matsumoto, M. 87 Nakagomi, S. 88 Park, S. B. 88 Richard, N. 84 Matsumoto, Y. 40 Nakamura, T. 44 Parsons, S. 82 Richardson, J. N. 39 Matsushima, T. 37 Nakane, H. 32 Parthasarathy, N. 132 Richter, J. 180 Matsuyama, H. 81 Nakato, Y. 83 Pasichnyk, P. I. 43 Riesen, H. 40 Matsuzaki, T. 43 Nakotte, H. 38 Pawlowski, V. 182 Rievaj, M. 137 Matulionis, E. 68 Nara, K. 45 Pazderskii, Yu. A. 43 Roberts, M. W. 41 McCabe, R. W. 85 Natarajan, M. P. 83 Pearson, J. M. 134 Robinson, R. A. 38 McGrath, R. B. 98 Neddemeyer, H. 183 Pedrero, M. 137 Rodriguez-Ramos, 1. 84 McIntyre, B. J. 13 Neely, D. 80 Pellegrini, P. W. 182 Romln-Martinez, McMurray, H. N. 183 Nefedova, M. N. 39 Pentin, A. Yu. 79 M. C. 84 McNichoU, R.-A. 133 Neiteler, P. 42 Pereira, C. J. 171 Ronchin, L. 86 Mednikov, E. G. 180 Neumann, K.4. 37 Perez-Murano, F. 182 Roobeek, K. F. 134 Meheux, P. A. 41 Ng, K. Y. S. 84 Perkas, N. V. 184 Ross, P. N. 82 Meldrum, E C. I80 Ni Dhubhghaill, 0. M. 45 Perng, T. P. 80 Rossi, R. 139 Menchikova, G. N. 40 Nicoloso, N. 134 Perrichon, V. 184 Rossin, J. A. 84

Platinum Metals Rev., 1995, 39, (4) 193 Page Page Page Page Rotondo, E. 44 Shen, J. Y. 43 Webe, H. 81 Viiegas, I. 82 Rousset, J. L. 42 Shephard, D. S. 82 Weda, N. 133 Vincent, H. 81 Rowlig, S. 87 Shldo, T. 139 Takeno, N. 82, 136 Viney, C. 86 Rozenberg, V. 1. 43 Shimada, S. 138 Tgkeuchi, K. 43 Vinogradova, L. E.I 82 Rozibre, J. I80 Shimada, Y. 141 M,M. 83 Viiovskf, s. 185 Ruckenstein, E. 138 Shlmizu, I. 134 lhmaru, Y. 139. 184 Vittal, J. J. 180 Rulz, A. 87 shimizu, Y. 83 'Igmura, H. 42 Vogler, A. 182 Ruppert, R 181 Shimura, T. 180 Tanaka, A. 139 Voitlilnder, J. 38 Rusetskaya, N. Yu. 174 Shindo, Y. 83 TBnaka, K.-I. 42 Volkening, F. A. 137 Russell, M. J. H. 65, 172 Shiono, T. 87 TBnaka, s. 139,184 voutov, P. 38 Rutherford, T. J. 181 Shirai, J. 140 lhaka, Y. 141 Voroatsov, E. V. 43,82 Ryan, M. E. 128 Shong, W. 167 lho, w. 141 Vorontsova, N. V. 43 Shu, C. 185 lhrdy, B. 42 Vos, E. J. 140 Sachtler, W. M. H. 41,183 Shu, J. 45 Tashiro, M. 86 Vos, J. G. 39, 182 Sadler, P. J. 45 Siegel, R. W. 37 'hylor, M. J. 87 Saha, D. K. 133 Shorn, K. E. 41, 138 Temkin, 0. N. 139 Wakabayashi, T. 184 Saito, N. 40 Sinn, E. 87 Teraoka, T. 32 Wakoh, K. 38 Saito, Y. 44 Slivinskii, E. V. 185 Tercier, M.-L. 132 Walker, J. M. 180 Sakakima, H. 185 Slutzky, M. 137 Teapier, M. 185 wan, c. c. 80 Sakata. T. 40. 135 Smetana, Z. 185 Thommett, D. 165 Wan, K. T. 62 Sakauchi, J. 138 Smirniotis, P. G. 138 Thombn, Wang, B. 37 Salanov, A. N. 81 Smith, G. D. W. 141 D. T. 27.62, 108,172 wang, c. 182 Salaiin, J. 86 Smith, J. G. 37 Thompson, M. 141 Wang, G. 138,183 Salinas-Mdnez Smyslova, E. I. 39 Thomson, J. 42 Wang, H.-L. 139 de Lecea, C. 84 Sobyanin, V. A. 88 Tielen, M. C. 42 W-3 J. 41,137 Salmemn, M. 13 Sokolov, A. L. 183 Togni, A. 185 wanp, L. 42 Saivatierra, D. 83 Sokolov, V. I. 38.39 Toktabaeva, N. F. 42 Wang, P.-w. 42 Sanchez, J. P. 134 Solovetskii, Yu. I. 185 Tokura, H. 80 Wm, w. 18 Santi, R. 140 Somora, M. 88 Tolosa, J. I. 140 Wq,W.-K. 81 Sasabara, A. 42 Somorjai, G. A. 13 Toma, P. I37 Warshawsky, A. 85 sasaki, K. 83 Song, H. 82 Tomiehige, K. 85 Wartnaby, C. E. 182 Sd,Y. 135 Sonoda, M. 141 Tong, X. Q. 133 Washburn, J. 180 Sato, N. 37 Soma, J. B. 38 Toniolo, L. 86 Watanabe, K. 40 Satomi, M. 185 Spirlet, J. C. 38 Toril, S. 181 Watanabe, M. 44.85, 135 Satyanarayana, N. 86 Spivak, G. J. 180 'Raldi, P. 134 Watt, R J. 87 Savadogo, 0. 44 Starchevskii, M. K. 43 'Randalllov, A. T. 137 Weaver, M. J. 82 Savchenko, V. I. 81 Sternlk, M. 81 Ikptow, B. 87 Webster, D. E. 73 Sawabe, K. 40 Stonehart, P. 44 Mbutach, H. 39 weinstein, v. 137 Sawamurn, M. 140 stuhr, u. 80 ?timm, D. L. 183 Weissmiiller, J. 80 Scaros, M. G. 65 Sturm, J. C. 182 Mvedi, D. C. 88 Wells, P. B. 41 Sehamp, A. L. 40 Su, H. 141 kt,B. M. 87,141 white. P. 107, 126 Schieck, R. 39 sugawpra, Y. 185 TrovareUi, A. 85 White; S. F. 41 135 Sehlaf, M. 135 S-9 B. 81 'Lheeiak, A. M. 44 Williams, D. S. Sehmalz, K. 134 sugi, y. 43 Isurumi, K. 44 Williams, E. W. 45 Schmld, R D. 41 SUgiYama, K. 31 lbmanskii, B. L. 38 Willinms,J. M. J. 86 Schmidtke, D. W. 137 SUgiyma, T. 141 nng, c.-Y. 138 Williams, P. 141 Scbnyder, A. 185 Sub, L-H. 134 'hrner, A. P. F. 41 WUson, B. D. 43 Schiitz, E. 141 sumiyama, K. 38 Tvmftek, V. 137 Winand, J. M. 38 Schuller, I. K. 80 Sun, H. 40 Window, B. 80 Schumann, J. 38 Sunley, G. J. 134 Udovic, T. J. 80 Winkelmann, F. 183 Scorrano, G. 135 Sutherland, I. M. 41 Ueki, T. 126 Wiubst, A. J. A. 133 Searles, R A. 112 SUZUki, K. 38 Uemura, S. 184 Wipf, H. 80 Sechovskj, V. 38 Svoboda, P. 38 Ueno, H. 81 woodward, s. 87 Seddat, M. 185 Swain, M. 80 uozumi, Y. 184 Worsley, D. 44 Seido, N. 87 Sweetmnn,M. J. 42 Usatov, A. V. 82 Wrigbton, M. S. 140 Sekine, S. 141 Sykes, A. G. 179 Usmen, R. K. 85 wu, L. 37 Sellinger, A. 86 Uttlch, T. 183 wu, 2. 37 Semenova E. L. 174 Senateur, j. P. 37 'hgo, T. 83 Van Bekkum, H. 183 Xi, c. 136 Sepulveda-Escrlbano, Tpkabara, N. 180 Van Leeuwen, Xiao, J. 180 A. 84 'hkabashi. M. 180 P. W. N. M. 86,134.140 X~O,T.-C. 139

Seraglia, R. 134 Takahefh;N. 138.. ~ Van Rooy, A. 86 Xiao. X. 182 Seret, A. 38 'Igkano, N. 82,136 Vanicky, D. 88 xu, L. 81,181 Sergeeva, E. V. 43 Takaoka, s. 37 Vargaftik, M. N. 43 xu, Y. 38, 126 Shanklln, M. S. 44 mlkas- Y. 39.82 Vermaak, C. F. 116 Shapovalova, L. B. 43 Takaya, A. 87 way, D. P. 45 Yagita, H- 184

PlannumMeraLc Rev., 1995,39, (4) 194 Page Page Page Page Yahikozawa, K. 39.82 Yeo, Y. Y. 182 Zang, T. 42 Zheng, G. Z. 88 Yahiro, H. 85 Yoo, I. K. 45 Zannoni, G. 181 Zhou, L. 37 Yamamoto, A. 134 Yoshida, A. 181 Zayer, N. K. 37 Zhou, Y. 18 Yamamoto, T. 88 Yoshida, K. 32 zhan, z. 183 Zhu, Y. 184 YillUaShita, H. 84 Yoshimori, Y. 184 Zhang, D. 167 Zlebeck, K. R. A. 37 Yanagi, K. 184 Yu, K. M. 180 Zhang, M. 184 Zikrina, Z. A. 79 Yang, N.-H. 139 Yu. s. 184 Zhang, Q. 167 ZWkowskI, J. J. 44 Yang. S.-M. 8R Zhang, Y. 81 ZloLazov, M. V. 44 Yang, z. 19 Zakumbaeva, Zhao, H. 19 zou, w. 138 Yasui, K. 139 G. D. 42,43, 184 Zheng, D. 139 Zung, T. T. 139

SUBJECT INDEX TO VOLUME 39 Page Page a = abstract Butane, reactions, a 42,85 Acetcenes, reactions. a 42,136,140, 184 ButenoUdes, synthesis, CpRu(C0D)CI catalysed, a 141 ACT , pgm coating technology 98 Acyclic Compounds, hydrogenation, on Pt, a 183 C-H Bonds, addition to olefins, a 141 Advanced Coating Technology, ACTM 98 Cancer, anti, rrans-[RuCl,(Him),]- complex, a 45 Alcohols, 2-alkanols. synthesis, on Pd catalysts, a 184 chemotherapy, conference 63 electro-oxidation on Ru(VU)/Ru(IV), a 181 Pt drugs, binding to DNA, a 141 methyl, electro-oxidation. at FY, Ru, Pt-Ru, a 82,181 Rn compounds in NO mediated disease 150 oxidation, by P&,Phenm(OAc),,, a 43 Ru phthalocyanines. for photodynamic therapy 14 Rh carbonylahon catalyst, a 87 Capacitors, RuO b(Zrfl)OJRuOz with Pt interlayers 64 optically active, production, a 140 Carbon Oxides, &, electroreduction, on Pd. Pt. a 39 primary, aromatic. oxidation, by RuO,, a 88 at Pt gas diffusion electrode, CH, production, a 135 Aldehydea, benzaldehyde, allylation, a 139 CO, adsorption at Pt, Ru, Pt-Ru electrodes. a 82 branched, from Rh chiral catalysts, a 140 hydrogenation, on Rh/Mo/SiO a 43 formaldehyde, hydroformylation, on Rh, a 185 interdiffusion in Ru pellets, foYFischer-Tropsch. a 43 oxidation, by RuO,, Q 88 oxidation, over CuO-Pdy-Al,O,, a 184 from primarylsecondaq alcohol electro-oxidation, a 18 1 reaction with NO and H over Pt, Rh catalysts. a 183 yield, from pentane carbonylation,a 40 for triarylbismuthines carbonylation,a 184 Alkenes, addition reactions, via Ru complexes, a 87, 141 Carbonyl Compounds, a$-unsaturated, hydmsilation. Q 88 I-alkenes, asymmetric hydrosilylation. a 184 CarbonylPtion, aryl iodides, by F’dq(PPh&€%(CO),. a 139 hydroformylation, by Rh(1) complexes, a 44 by PdCl,(PPh,),-Ru(CO) 2, a 139 isomerisation, by Rh complex, a 140 halogenoalkynes to alkynytcarboxylicacid esters, a 139 Wacker oxidation, a 42 MeOH, by Rh complex, a 87 Alkenyl Halides. coupled to aryl-alkynyl20 chlorides, a 139 pholo-. pen-. in Rh&%(CO), + PMe,, a 40 2-AUryleminooxazoles, high yield synthesis, a 87 triarylbismuthines, with CO, a 184 ccAUrylstion, hydroxyalkynoates, via CpRu(C0D)Cl. a 141 Carboxylates, production using Ru chiral complexes, a 185 Alkyues, addition to alkenes, by Ru complexes, a 87 Carboxyk Adds. acetylene addition, by Pd cluster, a 184 Akynylcarboxylic Acid Esters. production, a 139 Catalysis, biphasic I07 l-Alkynylzinc Chloride coupled to alkenyl halides, a 139 heterogeneous, a 4143,8445, 138-139. 183-184 Allenyl Tosylcarbamates, cyclisation on Pd, a 184 homogeneous, a 43-44.86-88. 139-141, 184-185 Ally1 Acetates, reaction with sodicdimethylmalonate,a 86 modelling techniques 171 Allylamiweyellzation,allenyl tosylcarbamates, a 184 review of the 14th N. Am. Catalysis Soc. meeting 126 AUylation. benzaldehyde. (I 139 Catalysts, automotive. new Mexican plant opens 72 AUyloxyaromatic Esters, reactions, a 86 review of 2nd European Precious Metals Cod. 112 AUyKianes, synthesis, a 86 SAE conf., 1995 73 Ammonia,oxidation, Pd alloy catchment gauzes 19 biphasic Rh systems 62 sensor, a 182 electro-, Pt-AYC, for SOz oxidation, Q 135 synthesis, from N,, a 83 industrial, book review 65 [Ru9N].clusters for, a 139 phase transfer, a 88 Aromabsshoqalkanemvrtures, on Wmlite composites, Q 138 Iridium Comdexes. Ir chloro comulexes. Aryl Halides, reactions, a 139 H isotipe exchange in aromkics, a 140 Arylation, Heck, on benzene-Pd(U)/polymer, a 42 [Ir(COD)(~’-~,PCH,CH,OMe)l[BF,I, 2-Arylbenzothiazoles,new synthesis, a 43 pheny lace~lenebydsilylation; a 140 Aryldiazonium salts, Heck reaction, a 183 wundium, SSPd/BaSO, for 0-benzyl hyhxamates. a 85 Pd(ll) complex/polymer. for Heck arylation, a 42 Bdard Bus, 4th Grove Fuel Cell Symposium 160 CuO-Pdr-AI,O,. for CO oxidation. a 184 Biofuels. glycerol oxidation 159 glycerol irom‘ra’peseed oil, oxidation 159 Book Reviews, “Catalysis of Organic Reactions” 65 Pd colloids/NR *, preparation, stabilisation. a 42 “Catalytic Naphtha Reforming, Science & Technology” 27 Pd-Culreolite. tor Wacka oxidation of alkenes, a 42 “Computer-Aided Design of Catalysts” 171 Pd/AI,O, methane combustion, a 84 “Insights into Speciality Inorganic Chemicals” 172 P~AI,~!.~dlz~o,, SO, propane oxidation eficst, a 84 “Metal Compounds in Cancer Therapy” 179 preparat~on,liquid-phase hydrogenation activity, u 184 “Phase Diagrams of Recious Metal Alloys, First Suppl.” 18 selective acetylene hydrogenation, a 42 “Rhodium Express” 78 PdK + AsPh,. for cross-coupling reactions, a 139 ‘The Platinum Group Metals: A Global Perspective” 116 Pd/C, A1 0 , SO,, BaSO,, for Heck reaction, Q I83 Butadienes, reactions a 42,140 Pd/ceo,ldteractlon with H,, a 184

Platinum Metals Rev., 1995, 39, (4), 195-200 195 Page Page Catalysts, Palladium (conrd.) Catalysts, Rhodium Complexes (conrd.) Pdpolymer microdispersions, H, generation, a 85 (ph,),RhH, hydrosiition of c*punsaturatedcarbonyls, a 88 PdSiO,, Rh modified, ethene hydroformylation, a 138 Rh,CI,(CO), + PMe,, pentane photocarbonylation, a 40 Pd/WO,,, nanocrystalline, catalytic properties, a 138 [Rh2(~-(-)-DI0S)(cod),]~,styrene hydroformylation, a 87 PdEnO&Al,O,, CCl,F,, hydrogenolysis, a 42 Rh,(OAc),, for 2-alkylaminooxazoles synthesis, a 87 PdC1,(PPh3),-Co,(CO),, aryl j$de carbonylation,a 139 for cycloheptatnenes,norcaradiene synthesis, a 87 PdC&(PPh,),-Ru(CO),,, aryl iddecarbonylation, a 139 Rh,(CO),,, acetylene silylformylation, a 140 Pd(OAc), + AsPh,, for cross-coupling reactions, a 139 Rl-PPh,, catalyst regeneration,a 185 PdSAPO-5, one-step synthesis, a 139 Rh(acac)(P(OPh),)JP(OPh),, for hydroformylation, a 44 Ph,P[Pd(dba)JPh,P], oxysilylation reactions, a 86 RhCl,(Pybox), ketone asymmetric hydrosilylation, a 185 Palladium Alloys, Pd-Ni, butadiene hydrogenation, a 42 [RhCI(CO),l,, triarylbismuthines carbonylation, a 184 Palladium Complexes, ~dMo,S,(tacn),CI][,, a 184 [RhCI(CO),CI],, for poly(methylhydrosi1oxane).a 86 Pd@ba),CHCI,, cyclised, butzdienyl tosyl-, a 184 RhCI(CO)(PPh,),, formaldehyde hydroformylation, a 185 Pd,,Phen,(OAc),,. for MeOH oxidation, a 43 RhCl(PPh,),, for 2-propanol dehydrogenation, a 44 Pd-HC1, for H transfer from H,O-CO, a 86 RhCl(PPh,),, formaldehyde hydroformylation, a 185 Pd-MOP, 1-alkenesasymmetric hydrosilylation,a 184 for poly(methylhydrosiloxane), modification, a 86 [Pd(allyl)Cl], for ally1 acetate reactions, a 86 Rh(CO),acac, for hydroformylations, a 86 PdCl,.dppf, for [2.2]paracyclopbanes synthesis, a 43 [Rh(cod),]BF,, for hydroborations, a 185 PdCl,(dppf)/K,CO,, one-pot method for enamides, a 43 for keto esters hydrosilylation, a 140 PdCI,(Ph,P),, for styrene hydrocarboxylation, a 86 [Rh(COD)Cl)]pPTS, biphasic 62 PdCl,(PhCN),, cyclised butadienyl tosylcarbamates,a 184 [Rh(cod)(OOCR)I,, alkene hydroformylation, a 44 PdCI,(PPh ) , for 2-arylbenzothiazoles, a 43 [Rh(CO)(PPh,)(p-Cl)],, isomerisation, a 44 Pd(I1) + cy%c aminomethyl phosphines, a 43 [Rh(dppc)-(acetone)],hydrosilation, hydrogenation, a 140 Pd(OAc),:PPh,, for allylsilane synthesis, a 86 for ketones, alkenes reduction, isomerisation, a 140 Pd(OAc),, for enones, enals synthesis, a 139 [Rh(dppc)NEDI(PF,), precursor, isomerisation, a 140 for olefin hydroesterification, a 140 Ruthenium, hydrogenation, review, a 184 Pd(OAc),/PPh3/Naf2O,, enamide synthesis, a 43 [Ru,N] clusters, for NH, synthesis, a 139 Pd(0)L. for cyclodimerisation of butadiene, a 140 Ru, FeRu, F't, FeWC, pyridine hydrodenitrogenation,a 84 Pd(PPh,),, for benzaldehyde allylation, a 139 Ru pellets, Fischer-Tropsch. HJCO diffusion effect, a 43 for imidazo[4,5-b]pyridines phenylation, a 140 Ru-Cr-MdAl,O,, for CO hydrogenation, a 43 for tribromomethylbemneto diarylacetylenes, a 86 RuO,.xH,O, 0 catalytic activity, a 44 PdX,-LiX, for carbonylations,a 139 Ruthenium Complexes, Pd/pumice, phenylacetylene liquid-phase hydmge&on, a 139 for addition of C-H bonds to olefins, a 141 PdlWO,.,, nanocrystalline, catalytic properties, a 138 BLNAP-Ru(ll), olefin asymmetric hydrogenation, a 87 Platinum, for diesel filter trap 2, 114 chiral, with glass microbeads, in biphasic catalysis 108 EUROPT-1, compared with Pt catalysts, a 183 CpRu(C0D)Cl. for alkynes addition to alkenes, a 87 glycerol from rapeseed oil, oxidation 159 [Ru(a~py)~(H~O)@y)l'*,glucopyranoside oxidation,a 44 Pt(100). activity for NO+H, reaction, a 42 [RUCI,(C~~)(R,C(C=NCHR~R,O),)], Pt, cinchona-modified, pyruvate hydrogenation, a 41 for aerobic alkene epoxidation, a 87 Pt-AdSiO,, preparation, characterisation,a 85 trans-RuCl,(Pybox-ip)(ethylene), Pt-MFI zeolite, NO reduction, a 85 for asymmetric cyclopropanation, a 185 Pt-Nay, WSiO,, HY, n-hexane reactions, a 183 Ru(II)-bis(2-oxazolin-2-yl)pyridine, chiral, Pt-Sn/Al,O,, modified by Sm, Li, a 42 for asymmetric cyclopropanation of styrene, a 185 Pt-SdSiO,, for unsaturated nitrile synthesis, a 85 Ru(II)(AMPP),a-ketoesters hydrogenation, a 87 WAI,O,, for chlorobenzene hydrodehalogenation,a 183 RuO,, phase catalyst transfer, oxidation reactions, a 88 enantioselective ethyl pyruvate hydrogenation, a 183 Catchment Gauzes, Pd alloy 19 ethyl peruvate hydrogenation, a 138 Chemical Compounds, a 38-39.81-82, 134-135, 180-181 methane reactions, a 84, 138 chemicalTeehwlogy,cH,s~reforming, slurry-phase hydrogenation of phenol, a 41 in Pd mmbrane mcfor, a 45 in trickle bed reactor, naphthalene hydrogenation, a 183 Chlorobenzene, hydrodehalogenation, a I83 WAl,O,, Rh/AI,O,, adding H, to NO+CO, a 183 Chloroform, catalytic oxidation, a 84 WAl,O,/NiAI(l lo), model, characterisation, a 183 Cinnamic Acid Esters, production, a 183 WBaKL composite, to reform alkane mixtures, a 138 Clusters, K,.,Pt(C,O,),, on glassy C electrode, a 181 WC, metal-support interaction,a 84 Pd,,(CO),,L,,, synthesis, a 180 PdC, Rh/C, acyclic compounds hydrogenation, a 183 [Ru,(CO),,I2-, in NaX zeolite, 0 sensitive, a 139 Wy-AI,O,, Wzro,, SO,, propane oxidation, a 84 [Ru,N] for NH, synthesis, a 139 Pt/H-BEA, chlorobenzene hydrodehalogenation, a 183 Coatings, Ir, on isotropic graphite, thermal cycling, a 83 WH-mordenite, methylcyclopentane conversion, a 41 Pd, for semiconductor packages, a 138 WK-6A1,0,, for CHCl,, CH,H, oxidation, a 84 pgms, ACTTMtechnology for glass manufacturing 98 WSiO,, high surface area, preparation, a 138 Ru-Sn, on Ti, a 137 pt/zro,, superacid, butane isomerisation,a 138 See also Electrodeposition I't/WO,,, nanocrystalline, properties, a 138 Cobalt, in alloys, a 68.88 Platinum Complexes, See alsa Thin Films Pt- 1.3-divinyltetramethyldisiloxane,a 86 Colloids, palladium, catalysts, preparation, a 42 PtBaKL zeolites, reforming alkane mixtures, a 138 Ru,S, preparation. luminescence, a 40 Rhodium, Rh/Al,O,, preparation, a 85 Composites, a 133,134 Rh/CeO,-ZrO,, 0 exchangers, a 85 Conferences, 14th Fuel Cell Seminar, Rh/F't(lOo), NO + H, reaction, a 42 San Diego, CA. Nov.-Dec. 1994 9 Rh/SiO,, promoted by Mo, CO hydrogenation, a 43 14th N. Am. Catalysis Soc, meeting, MnO,for N,O decomposition, a 184 Snowbird, Utah, June 1995 126 Rhodium Complexes, in biphasic catalysis 108 1st Int. Workshop on Diffusion and Stresses, cis-[RhI(CO)(Ph,PCH~P(S)Ph,)], Kossuth Univ., Hungary, May 1995 127 activity for MeOH carbonylation, a 87 1st Int. Symp. Fuel Cell Systems, (I~-c&BF%+ooD), acetylene silylfonnylation,a 140 Montreal, 9-13 July, 1995 165 HRhPP(CO),, for asymmetric hydroformylation, a 140 2nd European Precious Metals, Lisbon, May 1995 112

Platinum Metals Rev., 1995,39, (4) 196 Page Page Conferences (contd.) Electrodes, anodes, platinised Ti, a 88 4th Biennial Int. Symp. on Metal-Hydrogen Systems, cathodes, F't/Y,O, stabilised Zro,, a 181 Fujiyoshida, 6-11 Nov. 1994 75 chlorosilylatedPt oxide surfaces, a 39 4th Grove Fuel Cell Symp., London, Sept. 1995 67, 160 interdigit array, WionPt-IDA,trace k analysis, a 137 6th Int. Conf. on Platinum Group Metals, microelectrodes, Ir, for water quality testing 132 York Univ., July 1996, announcement 111 K, uPt(C,0,)2. a 81 7th Int. Symp. on Metal Co-ordination Compounds in Pd, for Pd-Li alloy formation from eutectic melts, a 83 Cancer Chemotherpy, Amsterdam, March, 1995 63 Pd microparticles/poly-[N-(5-hydroxypentyl)-pyrrole] Electrochem '95, Bangor, 10-14 Sept. 1995 173 film, for C,H, hydrogengation. a 136 "Noble and Rare Metals", Pd poly(N-pyrro1e)film-coated, a 82 Donetsk, Ukraine, Sept. 1994 29 Pd/Pt, for CO, reduction, at + potentials, a 39 SAE, Feb.-March 1995, Detroit 73 Pt, surfaces, for MeOH electro-oxidation, a 181 Corrosion hteetion, Ru in stainless steel 107 gas diffusion, for CO, reduction, a 135 in RuO,.xH,O, a 44 K,,,Pt(C,O,)Jglassy C fibres, ultramicroelectrodes, a 18 I Crystals, h5Ru,-xS2.a 39 Ru, Pt-Ru, CO adsorption, a 82 nano, Pd, in H, sensor, a 137 WC, highly dispersed, fabrication, a 135 PtlWO,,, PdlwO,-,, catalytic properties, a 138 Wy-MnO,, for Li ion insertion, a 135 Cyclisations, 2,3-butadienyl tosylcarbamates, by Pd, a 184 Wmodified glassy C, for monohydrics, polyhydrics, u 182 Cycloaddition, reactions, a 87 WpHAPh, rotating disc, a 82 Cycloalkanol, Cycloalkanone, production, a 183 Wi/Pt/Au base, for bipolar transistors, a 141 Cyclodimerisation, butadiene, by Pd complex, a 140 Rh-dispersed Cpaste. for lactate biosensing, a 137 Cvcloheutatrienes. svnthesis. a 87 with IRh(bovL1'. for nicotinamide reduction. a 83 Cyclohekne, hydrofknylation, by Rh catalysts, a 86 [Rh(bpy);]''it;~drogel, for nicotinamide reduction, a 83 Cyclowntene. hvdroformvlation. a 44 Ru,S colloids/liO,, sensitisation.a 40 Cyclopmpanation, asymmktric, styrene, dimacetates, a 185 Rub2. reactive ionetching, a 45 Ru0,-glass, composite, for pH sensing, a 183 Debrominative Coupling, reactions with Pd catalysts, a 86 wire, with 0s complex for glucose detection, a 137 Dehydrogenation, reactions, a 42,44 Electroless Depasition,, Ni, aided by Pd/Si( 110). a 80 Dehydropipernonalines, synthesis, a 43 Emission Control, in diesel engines 2, 114 Deposition, Pd-Fe alloys, electrolytically, a 40 technology 113 Rh on brass, a 40 SAE conf. 73 Desorption, Hz. from Pd, Ru-Pd foils, a 133 Emitters, Pd silicide coated Si, a 141 Detectors, air humidity, a 41 Enals, production from enol silanes, a 139 air-fuel ratio for automotive exhaust, with Pt, a 40 Enamides, conjugated, one-pot synthesis, a 43 biosensor for Pt anticancer drugs, a 141 En01 Silanes, conversion to enones, a 139 DNA, a 84 Enones, from en01 silanes, a 139 glucose, a 41.54.137 Epoxidation, aerobic alkene, Ru complex promoted, a 87 H,, a 41, 137 Esters, keto, hydrosilylation,a 140 R a 182 Etching, dry, Pd thin films, by F sputtering, a 84 lactate biosensor, a 137 Ethene, hydroformylatlon, on Rh-modified PdSiO,, a 138 monohydrics, polyhydrics in flowing streams, a 182 Ethyl Peruvate, hydrogenation, over WAI,O,, a 138 NH,, by WGaAs porous Schottky diode, a 182 Ethyl Pyruvate, enantioselectivehydrogenation, a 183 PH, a 183 Rh, a 182 Feeder Tubes, coated by Johnson Matthey ACTm 98 Deuterium, absorptioddesorption, diffusion, a 80, 181 Pt, for hollow glassware, a 141 Diarylacetylenes, catalytic production, a 86 Fibre Optics, in air humidity sensor, a 41 l&Diarylethenes, catalytic production, a 86 Films, PLZT on (1 1I)qt/riSiOJSi, for memories, a 141 Diazoacetates, asymmetric cyclopropanation, a 185 Pt, sputtered, properties, a 80 Dichloromethane, catalytic oxidation, a 84 Filters, for diesel engine emissions 2 Dienamides, conjugated, one-pot synthesis, a 43 Foils, Pd, Pd alloys, H absorptioddesorption, a 80, 133 Diesel, reduction of NO in exhaust, a 85 Formic Acid, electro-oxidation, a 82 trap, review of 2nd European Precious Metals Conf. 112 Fuel Cells, 14th Fuel Cell Seminar, conf. report 9 Diesel Engines, particulate emission control 2 4th Grove Fuel Cell Symp. 67, 160 Diffusion, H, D, in Pd. Pd alloys, a 80,127 a 44.88 Diodes, p'n, Pt diffused, in SiO, films, a 185 new materials, conference 165 Diphenylimidazo[4,5b]pyridines, synthesis, a 140 SPE, a 88 Dispersion, Pd in Pd/AI,O,, a 42 Fullerenes, [6o]derivative with Ru tris(bpy), synthesis, a 135 DNA, a 84, 136, 141 C -R-MV, photoreduction of H,O to H,, a 83 Doctoral Theses, CIS 79 (?-C,)Pt(PPh,),. a 38 Doping, see also Modifiers (q2-C,)Ru(C0).,, a 39 Drugs, metal based, book review 179 h-Cm, h-C70complexes, a 82 Os,-C, complexes, a 82 Electrical Contacts, ohmic, AulGelPd to n-type Inp,a 45 A-C,, Pt-C, complexes, a 81 PdGe to n-type InF', a 45 Pd/ln/Pd, Pd-In/Pd, Pd-Idn-GaAs, comparisons, a 88 Gas lhrbines, pinning wires for blades 117 Pd/zn/pd/Au to p-type InGaAs/InP, a 45 Glass, ACTm, pgm coating technology 98 PdEnSe, thin film, solid state reactions, a 180 RuO, composite, conduction mechanism, a 134 Electrical Engineering, a '5.88, 141,185 Glass Technology, a 141 Electrochemical Cell, PdfllSzIpd, NO, CH., removal, a 137 Glucose, sensors 41.54, 137 Electrochemistry, a 39.82, 135-136, 173, 181 Glyd,rapeseed oil by-producf oxidation 159 Electrodepasition, a 40.83, 136-137, 182 Glycolaldehyde, from formaldehyde, a 185 Pd-Fe alloys, a 40 Ru-COalloy 68 Halogenoalkynes, carbonylation, a 139 Ru-Sn on Ti, a 37 Heck,reactions, a 42,183 Electroless Depasition Heptine-1, hydrogenation, + aminomethyl phosphines, a 43

Platinum Metals Rev., 1995, 39, (4) 197 Page Page n-Hexane, reactions, a 138, 183 Iron, trace analysis, in ultrapure spectral C, a 137 Humidity, sensor, a 41 Isomerisation, butane, to isobutane, a 85 Hydridosilanes, reactions with allyloxyaromaticesters, a 86 [O~(~PY)(C~),(N)I’.a 135 HydriaosUoxanes reactions with aUyloxyan~mdicesters, a 86 [R~(CO)(P~,)(P-COI,,a 44 Hydmhoration. styrene, a 185 Isotope Exchange Reactions, H, catalysed by Ir. a 140 Hydrocarbons, synthesis, Fisher-Tropsch, on Ru, a 43 Hydmearboxylation, styrene, a 86 JM1226,new Ru drug 150 Hydrodehalogenation, chlorobenzene, a I83 Johnson Matthey, filter for diesel engines 2 Hydrodenitmgenation, pyridine, catalytic, a 84 JM1226,new Ru drug 150 Hydroesterification, olefins, by Pd catalyst, a 140 Mexican autocatalyst plant opening 72 Hydrolomylation, alkenes. by Rh(1) complexes, a 44 “Platinum 1995” 128 asymmetric, styrene, by Rh catalysts, a 87 Joining, Pd. Pd alloy electrodeposits,solderability, a 138 using HRhPP(C0) ,a 140 ethene, on Rh-mded Pd/sio,, a 138 a-Ketoesters, hydrogenations, a 87, 138 I-octene, by Rh biphasic catalyst 62 Ketones, asymmetric hydrosilylation,a 185 olefins, on Rh, catalyst regeneration, a 185 diaryl, from triarylbismuthines, a 184 reactions, on Rh(acac)(P(OPh))Jp(OPh),, a 44 from electro-oxidation of alcohols, a 181 Hydrogen, desorption from Pd, ku-Pd foils, a 133 isomerisation, by Rh complex, a 140 diffision in Pd, Pd alloys, a 80, 127 effects in metals, conference 29 Lactate, detector, a 137 effects in Pd, Pd alloy-H, p-c(n)-T, a 133 Lasers, trimming Pt thin films 129 induced ordering in Pd-Au, a 133 Legislation, automotive, reviewed at conf. 112 interaction with PdCeO,, a 184 Liquid Crystal Polymers. formation, a 86 interdiffision in Ru pellets. for Fischer-Tropsch. a 43 Lithium, a 42. 135 isotope exchange reactions, Ir catalysed, a 140 Lithography, using Pd as proton source 32 in Pd-H, Pd alloy-H systems, conf. 75 Luminescence, in air humidity sensor, a 41 photoevolution, a 83 lyoluminescence, in Ru(II)tris(bpy)chelates, a 182 reaction with NO, over RhPt( 100). a 42 in Ru compounds, complexes, a 40.82.83 reaction with NO and CO over Pt. Rh catalysts, a 183 Lyolumineacence, in Ru(n)tris(bpy)chelates,a 182 sensitive Pd-Si MIS. a 88 sensors, a 41, 137 Magnetism, in annealed Cc-Pd-Si amorphous alloys, a 133 separation by Pd impregnated AI,03 membrane, a 88 in BaFeIrCoO, a 81 solubility, vibrational modes in nanocrystalline Pd. a 80 Co-FVWpedoy sandwiches, magnetoresistance, a 141 sorption, in @n Pd, Pd alloy foils, a 80 ferromagnetism, in CrIrO, a 134 storage by bicarbonatelformate reaction, a 85 in P&TiAl, a 37 hlinsfer to p-benzoylacrylic acid, Pd catalysed, a 86 high field magnetisation of Upd,Al,, a 37 Hydrogenation, 1.3-butadiene, on Pd-Ni alloys, a 42 in SrLaZnRuO, a 38 acetylene, on Pd, a 42, 136 in U,Pd.Jn, U,Pd,Sn, a 38 asymmetric, a-ketoesters, by Ru(II)(AMPP), a 87 Magneto-Optics, a 185 olefins, by BINAP-Ru(II) complexes, a 87 CoPd multilayer films, a 88 CO, on RhlMolSiO,, Ru-Cr-Mn/Al,O,, a 43 spin valve memory, Co-Pt/Cu/Ni-Fe-Co/Cu, a 185 enantioselective, of ethyl pyruvate, a 183 Medical, a 45, 141 ethyl peruvate, over PtlAI,O,, a 138 Membranes, Pd, impregnated Al,O,, H2 separation, a 88 heptine-1, by Pd(lI) + cyclic aminomethyl phosphines, a 43 Pd, W/Ag/stainless steel, steam reforming m,a 45 liquid-phase, on PdyAl,03, a 184 ultrathin on porous ceramic, sputter deposited, a 136 naphthalene, a 183 Memory, PLZT films on (lll)PfI3iSiOJSi, a 141 0-containing acyclic compounds, a 183 Methane, adsorbed & photoirradiated. on Pt( I1 I), a 40 phenol, slurry-phase, a 41 catalytic combustion, a 84 phenylacetylene, on Pdpumice, a 139 oxidation, over Pt, in SPE fuel cell, a 88 pyruvate, enantioselective. on WAl,O, catalysts, a 138 by cinchona-modified Pt, a 41 removal by Pd/YSz/pd electrochemical cell, a 137 on Ru catalysts, review. a 184 steam reforming, in Pd membrane reactor. a 45 Hydrogenolysis, 1,1,2-trichlorotrifluorthane,a 42 Methyl Esters, fmn triarylbismuthines, a I84 Hydrosllation, a,p-unsaturated carbonyl compounds, a 88 Methylcyrlohexsw, refonning,,on Pt5aKL composite, a 13X Hydrosllylation, reactions, a 140, 184,185 Methylcyclopentane, conversion, a 41 Hydroxyalkynoates, a-alkylation, a 141 reforming. over WBaKL zeolite composite, a I38 Hydroxyls, detector, a 182 Mexico, Johnson Matthey autocatalyst plant 72 Microelectronics, Pd source of protons for lithography 32 Imidazo[4,S-b]pyridines, phenylation. a 140 Mineralogy. in CIS, conference 29 Indium, in electrical contacts, Electrical Contacts Modiiers. Sm. Li, on PI-Sn/AI,O,. a 42 Infrared,detector, a 182 Molybdenum, promoter for Rh/Mo/SiO,, a 43 Iridium, coatings on graphite, thermal cycling, a 83 MultllPyers, Cbwcu/Ni-FeCa/cu. memory elements, a 185 compounds, BaFeIrCoO, a 81 Pt/(NiCo), for magneto-optics,a I85 CrIrO, ferromagnetism in, u 134 IrH(CO)(PPh,),, reaction with C, & C, fullerenes, u 82 Nanocatalysis, by R-Rhtip 13 IrXRu&. crystals, a 39 NanocrystPLLites. Pt-Pd, in a Langmuir trough. u 180 in microelectrodes. for testing water quality 132 Nanoparliclea. Rh-PI colloids, structure. a I no Iridium Alloys. Ir-Pt, tips for SEM,a 137 Nanotechnology, by R-Rh tip, for nanncadysib 13 Iridium Chlorides, for highly acidic catalysts, a 85 fabrication of nanophase Pd, a 37 Iridium Complexes, [MeCOIr(CO),I,]‘, synthesis, a 134 seeelrpm- Iridium Oxides, films, sputtered, a 84 Naphtha. reforming, book review 27 Ir0,-Ru02-Ti0, powders, preparation, a 39 Naphthalene. hydrogenation, a 1x3 IrO -SnO, ultrahe binary oxides, sol-gel production, a 82 Nickel, electroless deposition. aided by PdSi(100). a 80 sr2h6,perowkite structure, a 135 NHrile9. unsahuapl, synthesk~from NO-alkandaJkene, a 85 Iridium Siliddes, IrxSi,.x,thin films, properties, a 38 Nitrogen, reductlon. on irradiated (Ru. OSlTiO,). a 83

Ratinurn Met& Rev., 1995,39, (4) 198 Page Page Nitrogen Oxides, N,O, decomposition on RhEnO, a 184 Palladium Alloys (conrd.) NO, in the body, Ru compounds for 150 Pd-Ag, foils, H absorption studies, a 80 in diesel exhausts, reduction on Pt-MFI zeolite, a 85 porous stainless steel, in membrane reactors, a 45 reaction with CO and H over h,Rh catalysts, a I83 Pd-Au, H induced ordering, a 133 reaction with H2, over RhPt(lM)), a 42 Pd-Co-Si, amorphous, annealing, magnetisation, a 133 removal by PdNSZTd cell from gas flow, a 137 Pd-Fe, electrolytic deposition, a 40 NMR,of %I, '"Ru in h.c.p. Ru, a 38 Pd-Li, eutectic formation on Pd electrodes, a 83 Norcaradiene, synthesis, a 87 Pd-5%Ni, ammonia catchment gauzes 19 Pd-rare earths, formation from eutectic melts, a 83 0-Benzyl Hydmxamates, deprotection by PcUBaSO,, a 85 Pd-5%l+, D, loadings, a 181 Octenes, hydroformylations, on Rh catalysts, a 62,86 Pd-Ru, foils, H absorption studies, a 80 Octyl-D-Glucuronic Acid, synthesis, a 44 H desorption, a 133 Octyl-a-D-Glucopyranoside,oxidation, by Ru, a 44 for pinning wire in gas turbine blades 117 Oletins, reactions, a 87, 140, 141, 185 shape memory effect 126 Osmium, the densest metal 164 Palladium Chlorides, for highly acidic catalysts, a 85 red?" polymer,. [0~(bipy)~~VP),~C!]Cl,stabfiation, a 39 Palladium Complexes, P%(dppm),Cd*, photoaddition, a 136 Osmium Chlondes, for hghly acidic catalysts, a 85 low valence complex, with n-acceptor Iigands, a 180 Osmium Complexes, Os,-C, fullerenes, clusters, a 82 rrans-[PdPh(py)(PMe,),IBF,, synthesis, a 134 Os,(CO),,(NCCH,), cluster growth on surfaces, a 82 trans-[PdPh(solvent)(PMe,),]BF,, synthesis, a 134 0s bi@henanthmline)dipyridophenazine, DNA probe, a 84 Palladium Sicides, formation studies, a 37 0sbipyridyl redox polymers, for glucose electrodes 54 Pd,,Si,,, amorphous, heat of crystallisation,a 81 [Os(bpy),]'+, fast efficient energy transfer, a 136 bulk nanophase, prepared by quench melting, a 81 [Os(~2-H,)(CO)(quS)(PPh3~2~+,synthesis. a 135 PdSi, Pd,Si. phases in Pd thin films/( 111)Si. a 80 [O~(QY)(C~)~(N)I9 a 135 Paracyclophanes, synthesis, by PdCl,Pppf, a 43 tnchlorostannyls, electronic, photo properties, a 182 Particulates. from diesels, filter emission control 2 in wired sensor, for glucose detection, a 137 Pentane, photocarbonylation, by Rh,Cl,(CO),, a 40 2-Oxazolidinones, synthesis, by Pd, a 184 Pentenolides, synthesis, CpRu(C0D)CI catalysed, a 141 Oxidation, chloroform, dichloromethane, a 84 pH, detection, a 183 CO, over CuO-Pay-Al,O,, a 184 Phase Diagrams, book review 18 electro-, MeOH & H,C02 at F't, Ru, Pt-Ru, a 82 Pt-Sn, a 37 electrochemical. SO,, with Pt-AUC black, a 135 Phenol, slurry-phase hydrogenation, on WAI,O,, a 41 MeOH, catalysed by Pd,,,Phen,(OAc),,,, a 43 Phenylacetylene, reactions, a 139, 140 methane, on WAl,O, catalysts. a 138 Phenylation. of imidazo[4,5-b]pyridines,a 140 in SPE fuel cell, a 88 Photoconversion, a 40, 83, 136, 181-182 octyl-a-D-glucopyranoside.by Ru catalyst, a 44 Photodynamic Therapy, with Ru phthalocyanines 14 propane, a 84 Photoelectrochemical Cells, a 83 Rh, a 81 Photolysis, in [(R~(bpy)~)~(bpzt)l'',a 182 Wacker, of alkenes, a 42 Pipernonalines, synthesis, a 43 Oxygen, reactions, a 37.85, 181 Plating, Rh, a I82 "Platinum 1999' 128 Palladium, in Au/Pd thermocouples, a 45 Platinum, cancer drugs 63, 141 bonding ability, a 138 clusters, K,,Pt(qO,)Jglassy C, ulhamiirroelectrodes,a 181 clusters, giant, Pd,,Phe~(OAc),,. MeOH oxidation, a 43 clusters, [n,(~-CO),(~-dppm),],first octahedral, a 180 large, Pd,(CO),(PEtJ,,, preparation, a 180 compounds, (q*-C,)Pt(PPh,),, a 38 Pd,,(CO),,(PR,) ,,. preparation. a 180 doping in SnO, thin films, electronic conduction, a 45 colloids, in catalysts, a 42 feeder tubes for glass production, a 141 complexes, Pd phosphine-phosphidte, a 134 in photoreduction of H,O to H,. a 83 composites, ZrOz(YSZ)-Pd,0 permeation, properties, a 133 Pt( 11 I), CH, adsorption, photoirradiated, a 40 compounds, Pd,TiAI, fernmagnetism, a 37 Pt(533), 0 desorption, dissociation, a 37 U,PdzIn, U,P&Sn, magnetic ordering, a 38 Pt100-hex and PtlW(1x I), surface energy, a 182 UP&Al,, magnetisation of, a 37 Wp-lnP( 100) photoelectrochemical cells, a 83 diffusivities of H, D, a 80 sputtered films, properties, a 80 foils, H absorption, H desorption studies, a 80, 133 in thermometry 45, 129 H effects in, p-c(n)-T, a 133 Platinum Alloys, Pt-Co catalysts, in PAFC, a 44 impregnated A1,0, membrane, for H, separation, a 88 R-H,WO, electrocatalyst, for PAFC, a 44 in magneto-optic multilayer films with Co, a 88 Pt-Ir, tips for SEM, a I37 membranes, a 45, 136 Pt-Ni, short range order, a 133 microparticles, in poly(N-pyrro1e)fdm electrodes, a 82 Pt-Rh tip, for nanocatalysis 13 nanocrystalline, H solubility, vibrational modes, a 80 Pt-Zr, Pt-Zr-Y, structure, dispersion strengthened 167 for solid state gas sensor, a 137 Platinum Chlorides, for highly acidic catalysts, a 85 nanophase technology, a 37 Platinum complexes,cluster, K1,,Pt(q04)2/C. synthesis, a 81 nanosize particles/Si(IOO). Ni electroless deposition, a 80 Pt-C,, Pt-C,, fullerenes, a 81 nuclei, activated on plastic, a 137 PtCl~-,,photoconversionin aqueous TiO,, H. CI, a 136 in P&Si layer in field emitters, a 141 [Pt(N2C(H)CO,)(PPh3),],fumarate derivatives, a 134 Pd-Ag powders, morphology, thermal properties, a 133 Pt@JO,),(NH,), for WCelectrodes, a I35 Pd-H, Pd alloy-H systems, conf. 75 Pt(qdt),l-, Pt(phen)(qdt), absorptiodemission, a 181 PdCu( 110) single crystal, surface analysis, a 80 low valence oomplex synthesis, rr-accepor Sgandq, a 180 pinning wires for gas turbine blades 117 Platinum Silicides, PtSi, thin film superconductivity, a 37 as proton source for lithography 32 PLZT films, on (1 1I)WrilSiOJSi. for memories, a 14 I with Si in tunnel insulator, H sensitive, a 88 Pollution Control, filter to remove diesel soot 2. 112 systems, Ce,P&Si,, heavy efectron system, a 133 in water, Ir microelectrode, to test Pb and Cd 132 dry etching, by F sputtering, a 84 Pdyme&ation, electm-, 2-hydroxy-3-aminophenazine.a 82 SeeeLEe Conferences; Thin Films Polymers, liquid crystals, formation, a 86 Palladium Alloys, Pd alloy-H, H effects in, a 133 redox, [Os(bipy),(PVP),,CI]C1, a 39 bonding ability, a 138 to support Ru, Pd catalysts 109

Platinum Metals Rev., 1995, 39, (4) 199 Page Page Poly(metbylhydmiloxane), modified by Rh, a 86 Ruthenium Complexes (contd.) Powders, Ag-Pd, morphology, thermal properties, a 133 Ru(lI)tris(bpy)chelates, lyoluminescence, a I82 Ir0,-Ru0,-Ti02, preparation, a 39 Ru(OEP)(H,PyP,P),, synthesis, a 135 Ru and Rudl,, a 38 [Ru(pp),(CO),]’+. chiral, decarbonylation, a 181 Promoters, a 42.43. I39 Ru(TAP),(2-TAP-G)’*, for metal-DNA binding, a 136 Propane, catalytic oxidation, a 84 ruthenocene auration, a 39 2-Propanol, dehydrogenation, a 44 trichlorostannyls, spectra, photochemistry, a 182 Pyridine, hydrodenitrogenation, catalytic, a 84 very large moiecules 33 Pyruvate, hydrogenation, by cinchona-modified Pt, a 41 Ruthenium Oxides, RuO,/Fe,O,, H, photoproduction, a 83 Ru0,-glass composite, conduction mechanism, a 134 Rapeseed Oil, glycerol oxidation 159 for pH sensing, a I83 Reactors, membrane, Pd, Pd/Ag stainless steel, a 45 RuO,-Ir0,-TiO2, powders, preparation, a 39 Reduction, cathodic, of nicotinamide by Rh(bpy), a 83 Ru0,-thermometers for mK range, a 88 electro-, CO,, on Pd/Pt wire net and plate, a 39 RuO,.xH,O, corrodability, 0 catalytic activity, a 44 on Pt gas diffusion electrode, a 135 Ruthenium Sulphides, RqS colloidsrr10,, luminescence, a 40 N,, over Ru, OsriO,, to NH,. a 83 Scanning Tunnelling Microscope, Pt-Ir tips, a 137 Schottky Diodes, in sensors, a 41, 182 n-hexane, over WBa Sensors, gx Detectors naphtha, book review 27 Shape Memory Alloys, Pd I26 steam. methane, in Pd membrane reactor, a 45 Silicon, Ru implanted, electrical, optical properties, a 134 Resistance Thermometers, a 45 Silylformylation, acetylenes, a I40 Resistivity, in LaRh,Si,, Ce(Rh,.,Ru,),Si,. a 38 SIROFS, u 84 Rhodium, compounds, CeLaRhSb, superconductivity, a 81 Sodiodimethylmalonate, reactions, Pd catalysed, a 86 LaRh,Si,, resistivity, thermopower, a 38 Sol-Gel Process, for powder production, a 39,82 Sr,Rh04, 2D conductor, structure, a I80 Sputter Deposition, pgm metals, u 80,84, 136 crack-free deposition on brass, a 40 Steel, stainless, Ru additions I07 detection, a I82 Stilhenes, epoxidation by Ru complexes, a 87 modifier. for Pd/SiO,, ethene hydroformylation, a 138 Styrene, reactions, a 86.87, 185 plating, a I82 Sulphur Dioxide, oxidation, with Pt-AUC black, a 135 Rh( 100) & polycrystalline Rh, interactions with 0,. a 81 Superacids, a 85, 138 Rh(III)/Cu(II), on Fe,O,, for H2 photoproduction, h 83 Superconductivity, in CeLaRhSb system, a 81 “Rhodium Express” 78 Superconductors, PtSi, ultrathin films, a 37 segregation in dilute Ag-Rh alloys, a 81 Sr., ,RunOln+,, perovskite 32 Rhodium Alloys, Rh segregation in, a 81 Rh-Fe, martensites, structure, a 180 Temperature Detection, by thin film sensors 129 Rhodium Chlorides, for highly acidic catalysts, a 85 Thermocouples, Au/Pd, stability, properties, a 45 Rhodium Complexes, [(9S3)Rh(p-SPh),MCp*lZ’, a 134 Thermometers, PI resistance, a 45 (HBPz*,)Rh(CO),, photochemistry, a I36 RuO,, for mK range, a 88 Li,RhH,, preparation, structure, a 39 Thermopower, in LaRh,Si,, Ce(Rh,,Ru,)2Si2, a 38 [Rh@py),]”/hydrogel. nicotinamide electroreduction, a 83 Theses, CIS doctoral 79 Rh“’I, voltammetry, for trace Rh detection, a 182 Thick Films, Ru02-glass composite, pH sensing, a 183 Ruthenium, additions to stainless steel I07 Ru0,-thermometers for mK range, a 88 clusters, [Ru,(CO),,]’, in NaX zeolite, 0 sensitive, a 139 Thin Films, Co-WCu/permalloy sandwiches, a 141 compounds, AI,Ru, semiconducting properties, a 38 Co/Pd magneto-optic, a 88 Ce(Rh,.,Ru,),Si,. resistivity, thermopower, a 38 lr.xSi,.x,electrical, optical properties, a 38 IrxRul~xS~,crystals, u 39 PbZrTiO, reactive ion etching, a 45 NO-mediated disease, anti-cancer activity I 50 Pd, dry etching, by F sputtering, a 84 Ru porphyrins, photophysical properties, a 82 Pd on (I 1 I)Si, silicides formation, a 80 SrLaZnRuO. solid solution, structure, properties, a 38 Pd on ceramic, ultrathin. by sputter deposition, a 136 SrRuO, superconductor 32 Pd doped SnO,, synthesis, a 37 effect on transformations in Ti-Ni alloys 174 Pd/Si, nanothin, multilayers, formation, a 37 implanted in Si, electrical, optical properties, a 134 Pd/ZnSe contacts, structure, a 180 nanocrystalline, production from RuAl powder, a 38 Pt, laser trimming, for temperature sensors I29 NMR of “Ru, ‘O’Ru,a 38 Pt, Pd, Pt-Pd, in a Langmuir trough, a I80 Ru(VII)/Ru(IV) system, alcohols electro-oxidation, a 18 I Pt in Pt/NiCo multilayers for magneto-optics, a 185 Ruthenium Alloys, Rudl,, production & leaching, a 38 Pt-doped Sn oxide, electronic conduction, a 45 Ru-Co, electrodeposition 68 PtSi, superconductivity, a 37 Ru-Pd foils, H desorption, a 133 Titanium Alloys, Ru in martensitic transformations I74 Ru-Sn, coatings on Ti, a 137 Transistors, AIGaAdGaAs, PfliAuelectrodes, a 141 Ruthenium Chlorides, for highly acidic catalysts, a 85 Triarylbismuthines, carbonylation, a 184 Ruthenium Complexes, [60]-fullerene derivative, a 135 Trichlorosilyl Alkanes, synthesis, a 184 anticancer, a 45 Trichlorotrifluoroethanes,hydrogenolysis, a 42 CpRuC,H4(AuPPh,),+BF4-, a 39 lbrbine Blades, pinning wire 117 dinuclear, macrocycles, with bpy units, a 181 ($-C,)R~(CO)4, a 39 Vinyl, compounds reactions, a 44. 140 [(pp),R~(BL)Ru(pp’),]~*, synthesis, a 181 Ru,C(CO),,(~’-C,H4PPh,),cluster, a 82 Wacker, oxidation, alkenes, a 42 Ru phthalocyanines, photodynamic cancer therapy 14 Water, photoreduction, by C,-R-MV, u 83 Ru polyaminocarboxylate, new drug 150 testing its quality, by Ir microelectrode 132 l(Ru(bpy),),(bpzt)l’*. photolysis, a 182 Wires, pinning, for gas turbine blades 117 Ru(bpy)2(daf)**.in zeolite Y supercages, a I36 [Ru(bpy),]’*,fast efficient energy transfer, a 136 Yttrium, added to Pt alloys I67 RNbpy),”, a 40,83 Ru(bpy)(bpm)(bpz), quenchers of luminescence, a 40 Zirconium, added to Pt alloys 167

Platinum Metals Rev., 1995, 39, (4) 200