UK ISSN 0032-1400
PLATINUM METALS REVIEW A Quarterly Survey of Research on the Platinum Metals and of Developments in their Application in industry www.matthey.com and www.platinum.matthey.com
VOL. 44 October 2000 NO. 4
Contents
Relativistic Phenomena in the Chemistry 146 of the Platinum Group Metals By Geoffrey C. Bond Platinum Films in Gasochromic Switched ‘Smart’ Windows 155
Jmdery Manufacturing Technology 156 By C. W. Cotti
High Breakdown Voltage of Au/Pt/GaN Schottky Diodes 157
Damping in Ruthenium Alloys 157 Platinum Metals-Based Intermetallics 158 for High-Temperature Service By Ira M. Wolff and Patricia J. Hill
Core/Shd Bimetallic and Trimetallic Nanoclusters 166
A Concise Encyclopedia of Catalysis 167 Reviewed by P. Johnston
Metathesis Catalysed by the Platinum Group Metals 168 By V. Dragutan, 1. Dragotan and A. T. Balaban
Silphenylenesiloxane Polymers 172
The Discoverers of the Platinum Isotopes 173 By J. W. Arblaster
Abstracts 179 New Patents 183 Indexes to Volume 44 187
Communications should be addressed to: The Editor, Susan V. Ashton, Platinum Metals Review, [email protected] Johnson Matthey Public Limited Company, Hatton Garden, London EClN 8EE Relativistic Phenomena in the Chemistry of the Platinum Group Metals EFFECTS ON COORDINATION AND CHEMISORPTION IN HOMOGENEOUS AND H!CTEROGENEOUS CATALYSIS
By Geoffrey C. Bond Brunel University. Uxbridge UB8 3PH, U.K.
It may atfirst sight seem strange that concepts developed by Albert Einstein in thefirst decade of the 20th century to explain the structure and dynamics of the cosmos should have any relevance to chemistry. However, it is now quite clear that the chemical behaviour of the heavier elements in particular is dominated by what are termed “relativistic effects”. This article explores the implications of this for the coordination and chemisorption of carbon monoxide and unsaturated hydrocarbons, and their reactions in homogeneous and heterogeneous catalysis involving the platinum group metals.
A khly significant feature of the chemistry of Group 10 and beyond, and it has traditionally been the elements at the end of the three Transition explained by electron occupation of the 4f orbitals Series of the Periodic Table is the close similarity to create the Rare Earth elements before the 5d that exists between the six elements with partially orbitals start to be filled. This has been held to pro- occupied 4d and 5d orbitals, that is, the group duce what is termed the “lanthanide contraction”, known as the “platinum metals”, and the marked caused by the inability of electrons in the 4f orbitals difference between them and the three elements to shield effectively the s electrons from the which have only 3d electrons, that is, the base met- increasing positive nuclear charge. The 6s orbital als (iron, cobalt, nickel). This difference also therefore contracts, and the expected increase in extends into Group 11, where gold and silver are atomic size does not occur (1,2). much “nobler” than copper. Part of the reason for this behaviour is that the size of the atoms increas- Chemistry of the Heavier Elements es on passing from the 3d to the 4d metals, but The heavier elements, that is, those having 54 there is no further increase on going to the 5d met- 6s or 6p electrons, show a number of unusual als, see Table I. This size difference is seen right physicochemical properties, many of which have across the Transition Series, from Group 4 to been interpreted in terms of other measurable
Table I Atomic Numbers, Z , Electronic Structures, Melting Temperatures, T,, Enthalpies of Sublimation, AHsut,, and Metallic Radii, r, for the Platinum Group Metals
Metal Electronic Structure Tm, K AHlub,kJ mol-’ r, pm
(Kr) 4d75s1 2655 648 132.5 (Kr) 4ds5s1 2239 556 134.5 0sIr 7877 (Kr) 4d” 1825 373 137.5 (Xe) 5d66s2 3318 784 133.7 “t (Xe) 5d76s2 2713 663 135.7 (Xe) 5d96s‘ 2042 469 138.5
Phtinzm Mutak Rw.,2000,44, (4), 14C155 146 Fig. I The forms ofaromic orbitcils: (i) s orbitals are spherically synmetrical (ii)p orbitals consist of three pairs of lobes, centred on each of the Curtesian axes (the p.;orbital is shown) (iii) d orbitals comprise the e, family, that is the dzz and dr2.!: (shown),and the tZg family, which contains three four-fold lobes centred on two of the Cartesian axes, each set being mutually at right angles (the d, set is shown)
parameters, such as ionisation potential, or by tivistic analogue of the Schrodinger equation, assigning a label, such as "the 6s inert pair effect", which incidentally predicted the existence of the which provides a comforting sense of understand- positive electron (positron), and accounted for the ing. However the underlying causes have remained occurrence of electrons having opposite "spins". uncertain, and there has been an increasing suspi- The difference which the relativistic correction cion, especially in the last 20 years, that the made to the energetic description of the hydrogen lanthanide contraction is not a full, perfect and atom was however very small, and it was therefore sufficient explanation for all that is observed. concluded that the chemical consequences were Among the anomalies are the greater stability of insignificant; but what was overlooked was the fact the Ppoxidation state compared to Pdw, the sta- that, as the positive charge on the nucleus increas- bility of the Au"' state, the varied colours of the es, the orbiting electrons must move faster in Group 11 metals, the low melting temperature of order to overcome the greater electrostatic attrac- mercury and the existence of the Hg? ion. tion and hence to maintain their position. When Numerous other unexplained aspects of the the nuclear charge is about 50 (at the element tin), chemistry of the heavier elements have been noted electrons in the lr orbital are moving at about 60 (1, 2). The quite startlmg properties of gold have per cent of the speed of light, and their mass is recently been rwiewed in depth (3): it has hgh increased according to the equation: electronegativity and can form the auride ion, Au-. p) = mo (l-v2c-y It owes its nobility to the instability of its com- pounds with other electronegative elements, such where mass m moves with speed v, cis the speed of as oxygen and sulfur. hght and mois the mass of the particle at rest. The 1s orbital therefore canfrucfs,and the outer s orbitals The Relativistic Analogue have to contract in sympathy, butp orbitals are less of the Schrodinger Equation affected, and d orbitals hardly at all: their shape The Schrodinger wave equation, describing determines that their electrons spend little time subatomic particle motion, which we were taught close to the nucleus, see Figure 1. to believe contained in principle the understan- of all chemistry, has in fact one major defect: it Relativistic Effects on the Properties does not treat space and time as equivalent, as of the Heavier Elements required by Einstein's Theory of Special Relativity. The net effect of all this can be illustrated by P. A. M. Dirac and, independently, the Dutch the results of recent calculations for the metals physicist, H. A. Kramers, therefore devised a rela- molybdenum, tungsten and seaborgium, (4), see
Pkztinum Metalr REV., 2000, 44, (4) 147 Fig. 2 This shows the calculated outermost atomic energy levels for molybdenum, tungsten and seuborgium (4). (ussutned to be unalogous to pulludiuni. platinum und eka-plutinum). The Ieji-hand purt for each element shows the tion-relativistic values (NR)nnd the right-hand part the values having the relativistic correction (Rel)
Figure 2. We may provisionally assume this also The extent of the relativistic correction to the applies to palladium, platinum and eka-platinum size of the s orbitals (and its smaller effect onp (element 110), respectively. The 6s orbital, having orbitals) increases approximately as the square of contracted, is thus lowered in energy, while the 5d the nuclear charge, and the total effect on the levels are raised in energy because the orbitals have atomic size is expressed as a “relativistic contrac- expanded. The spin-orbital splitting of thep and d tion”, that is, the fractional decrease in the actual orbitals is a particular feature of the relativistic metallic radius compared to the calculated non-rel- treatment (5-7). ativistic value, see Figure 3. This relativistic contraction is greatest for platinum and gold, but it subsequently decreases with increase in nuclear charge as the space occupied by the 6s orbital has 20 a diminishing effect on atomic size. It is now generally thought that the relativistic contraction is at least as significant, if not more so, than the lanthanide contraction for the 5d metals, 15 and that it is a dominant factor in the chemistry of elements having nuclear charge greater than 80 -L
2- (mercury). From the energy level diagram of Figure 0 2 we can understand why the electron configura- u 2 1c tion of palladium is 4d” while that of platinum is B 5d96s’, and why osmium and iridium have the 6s’ u configuration while ruthenium and rhodium are 5~’ L” (because the lower energy levels are flled up fist). 1 I-45 It also follows that the 5dmetals have higherionisa- wP tion potentials than the 4d (because the 6s level is of lower energy) and that they should have the greater bond strengths, with atoms both of differ-
C ent type and of the same type, as shown by the 60 70 80 90 100 sublimation enthalpies and melting temperatures ATOMIC NUMBER in Table I. This also explains why the (100) and (110) SUI- Fig. 3 Relutivisric contraction of the 6s electron level i a function of nuclear charge (redrciwn,~un7(4)) faces of only the 5dmetals undergo reconstruction
Phtinzm Mefah Rey., 2000, 44, (4) 148 in the absence of chemisorbed atoms. The small difference in the energies of the 6s and 5d levels, Figure 2, means that d-electrons can be more easi- ly removed or mobilised for bonding pqoses, thus accounting for the stabilities of the PtN and Aum oxidation states. Indeed, it would be an inter- e+ exercise to try to predict the properties of eka-platinum on the basis of calculated energy lev- Fig. 4 Molecular orbital diugrum for the linear bonding eL of the type shown in Figure 2. of carbon monoxide to u metal atom (14) The above observations and their interpreta- tion have been well described (3, 5-7), so it is of M(CO), of both metals can be made at very low more interest to explore less well documented temperature using the ma&-isolation technique areas. Inorganic textbooks (1,2)pay due regard to (9). The carbon monoxide can bond to one, two or the phenomenon of coordination of hgands to three metal atoms, and the nature of the bonding metal atoms and ions, and to the related reactions is well understood (1, 2). In the linear form of that occur in homogeneous catalysis, but little coordinated carbon monoxide, the 5p molecular attention is paid to the parallel phenomenon of orbital donates charge to a vacant d orbital on the chemisorption or to the resultant reactions of het- metal atom, and accepts charge from a fUed atom- erogeneous catalysis. These are no less interesting, ic orbital into the 27t molecular orbital, Figure 4, and in practical terms more useful, aspects of the but since both are antibonding the first strengh- inorganic/organometallic chemistry of the ele- ens the C-0 bond and the second weakens it. The ments. We ought therefore to look for evidence of two effects therefore tend to cancel out, but the the operation of relativistic effects in these areas, strength of the C-M bond depends on the extents to see whether they assist in understandmg and in of the two transfers of charge. rationalising what is seen. This will be done by The role of the relativistic effect is shown by considering: recent density functional theory (DFI') calcula- (a) carbonyl complexes, chemisorption of carbon tions on the first bond dissociation energy of monoxide and relevant reactions, and carbonyl complexes of the type M(C0)S and @) complexes and chemisorption of unsaturated M(CO), (lo), see Table 11. The agreement between hydrocarbons, and their reactions. In doing so it theory and experiment, where possible, is satisfac- will be necessary to engage in some rather broad tory. It is one of the triumphs of modern generalisations. computational chemistry that results can be
Coordination and Chemisorption of Carbon Monoxide Table II A very great deal of research has been per- Calculated and Experimental First Bond formed on the carbonyls formed by coordination Dissociation Energies, D, of Mononuclear of carbon monoxide to metal atoms (1, 2). Stable Carbonyls of Groups 8 and 10 (10) neutral complexes containing one or more metal atoms exist for all the metals of Groups 8 to 10 D, kJ mol-' exqt palladium and platinum, where the presence Carbonyl Experimental I Calculated I of either negative charge or of other hgands, such 176 192 as halide ion, is required for stability. The same is 118 138 true for the metals of Groups 11 and 12. Palladium 130 ~ 145 is different from platinum, however, in that it can- 105 124 - 50.5 not form polynuclear ionic complexes of the Chini - i 65.6 type (8), but neutral monatomic complexes,
Phtinnm Metah Rev., 2000,44, (4) 149 obtained on molecules such as Pd(C0)4 and 8 form complexes of the type M(PR3)d-L (15). Pt(CO), which do not exist as stable entities, When M is osmium there are four hydride ltgands, although the calculation correctly predicts very low but if M is iron or ruthenium there are two M-CO dissociation energies for them. Estimates of hydrides and one hydrogen molecule, the latter act- force constants for the Group 10 molecules ing as a (T' acceptor via its vacant antibonding O* M(C0) in matrix isolation provide confirmation orbital. DFT calculations show that this that nickel is a much better 0-donor and n-accep- changeover is due to the destabilisation of the tor than either palladium or platinum, although the osmium 5d orbitals, making osmium a stronger latter is the second best because the destabilised 5d donor. It is not yet known whether there are paral- levels, see Figure 2, allow more metal-to-ligand lel differences in hydrogen chemisorption. back donation (9). In Group 8, both theory and experiment show that the sequence of M-CO bond Homogeneous and Heterogeneous energies is Fe > 0s> Ru, for the same reason (10). Catalytic Reactions of Carbon Monoxide Much is also known about the chemisorption of The industrially and environmentally important carbon monoxide on metal surfaces and particles: catalysed reactions of carbon monoxide are: the nature of the bonding is very similar to that in (i) its reaction with hydrogen carbonyl complexes, and the fact that a surface (ii) its reaction with hydrogen and an alkene, that metal atom is linked to a number of others seems is, hydroformylation to have little effect. The sigdcant difference is (iii) its reaction with methanol, and however that the M-CO bond is stronger at sur- (iv) its oxidation to carbon monoxide. faces than in complexes, so that strong The reaction with hydrogen can lead to many dif- chemisorption is observed with palladium and ferent products, including methane, methanol and, platinum, and the adsorbed state can even be stud- by the Fischer-Tropsch synthesis, higher alkenes, ied on the Group 11 metals. alkanes and oxygenated products, depending on In fact, it is in Group 11 that the relativistic the catalyst used, and on the temperature and the effect is more clearly seen (1 1-13), but results from pressure at which the reaction is conducted. a recent important paper which analyses the situa- There are no significant applications of homo- tion with the Group 10 metals in great depth must geneously catalysed reactions of carbon monoxide be examined (14). In summary it concludes that with hydrogen alone. Laboratory studies have the chemisorption of a carbon monoxide molecule shown that HCO(CO)~can catalyse the formation on platinum differs from that on nickel and palla- of methanol, and rhodium cluster complexes can dium because there is: give 1,2-dihydroxyethane (ethylene glycol), but vig- a larger differential shift in C-0 vibration fre- orous conditions are needed, and they are not quency between the atop and bridge sites, and commercially attractive (1).
0 a smaller change in the work function of the All the many important reactions of carbon metal. These observations can only be explained monoxide and hydrogen require heterogeneous cat- theoretically on the basis of DFT calculations alysts. The metals which feature in Fischer-Tropsch which incorporate the relativistic correction. This synthesis are the three base metals of Groups 8 to is however of much less importance in the case of 10, and ruthenium and osmium. Ruthenium is able palladium, see Figure 2. to give very high molecular weight hydrocarbons at hlgh pressure. Palladium can catalyse the forma- Coordination of Hydrogen Atoms tion of methane, and rhodium can make CI and Molecules oxygenated products; the distinction here between In homogeneously-catalysed reactions in which these two metals and the others of Groups 8 to 10 hydrogen is a reactant, it must &st be coordinated is a clear reflection of the weaker bonding of car- to the metal centre: this usually occurs by dissocia- bon monoxide to their surfaces. In the same way, tion and oxidative addition. The metals of Group copper is the metal of choice for the industrial
Phhnwn Metah h.,2000, 44, (4) 150 synthesis of methanol, although gold also works, but much less effectively (3). The carbonylation of methanol to acetic acid was for many years operated with a homogeneous rhodium catalyst, although an iridium compound is now also used (the C&vu process) (16). This is one of the very few examples of the use of iridium in industrial homogeneous catalysis.
Coordination and Chemisorption I of Unsaturated Hydrocarbons Fig. 5 Molecular orbital diagram for the bonding of ethene to Pt " in [PtCldC2Hd)]- (the anion of Zeisek Much work has been performed on these sub- salt). Note that there are other Cl- ions in.front of and jects (1,2, 17-19), so it is necessary to draw some behind the platinum atom broad generalisations and to select just a few examples for closer attention. Many metal atoms metal species, the nature of the other llgands and and ions coordinate alkenes, alkynes and alkadi- the substituents on the alkene, mean that there is a enes, and these molecules are also strongly continuous range of structures, from an almost chemisorbed by the metals of Groups 8 to 10. unaltered ethene molecule through the ox: com- plexed Zeise's salt structure to the ethane-like Ethene metallocydopropanemode, rather than there being Most work has been done on ethene, so it will dearly divided classes. be discussed first. The archetypal complex is It is difficult to find quantitative information Zeise's salt, KptCl3(C2&)].H2O, in which the on the strengths of the coordinate bond between ethene molecule coordinates sideways on to the ethene and metal atoms or ions. There is however PP ion. The C-C bond is stretched and the hydro- a general impression that platinum complexes are gen atoms move backwards, see Figure 5. The more strongly bonded than palladium, due to the bond is very similw to that described above for greater spatial extension of the platinum's 5d carbon monoxide: electrons pass from a filled x: orbitals, and the larger orbital overlap which is orbital into a vacant d orbital on the metal @vhg therefore possible. This impression is confirmed the 0 component) and there is a reciprocal trans- fer back of electrons from a filled orbital into a vacant antibondmg R' orbital of the ethene (the R component). Similar coordination occurs with other metal atoms and ions of Groups 8 to 10, and with the univalent cations of Group 11, although here the bondmg is weaker because there are no vacant dorbitals on the metal. There are also com- plexes of the type Mo(PR3)Z(C2H4) in which the geometry is distorted tetrahedral, see Figure 6. The bonding has predominantly R character, again because of the absence (ii the case of palladium) or lesser availability (in the case of platinum) of d-orbital vacancies. The coordinated ethene molecule may therefore be considered to have a Fig. 6 Molecular orbital diagram for the bonding of metallacyclopropane structure. The variable ethene to Pto in Pto(PPh~)2(CzH4):electron donation from ethene is supposed to be to a partly-filled dp2 extents of the two types of orbital overlap, hybrid orbital on the metal. This complex is almost dependmg upon the electronic structure of the planar: the phenyl groups are not shown
PMmm Me& Rev., 2000,44, (4) 151 DFT, and are, in both cases, smallest for palladium, see Table III, (21). Similar structures to those seen in coordination complexes have also been identified when ethene is chemisorbed by metal surfaces or particles (17-19). Indeed, a simple-minded theoretical basis for the correspondence was pre- sented in the mid-1960s (22). In particular the 7~0form (as in Zeise’s salt) is seen at low temperature or high sur- face coverage on a number of surfaces, and an analogue of the metallacyclopropane form may also have been detected, see Figure 7. However, because multi-atom sites are available, other structures can arise, especially the 0-diad- sorbed ethane-like structure where each carbon atom forms a 0-bond to two metal atoms, as shown in Figure 7, (23). The only analogy for this type of structure in organometallic chemistry is the complex OSZ(CO)~(CZH~),which may also owe its existence to the relativistic d orbital destabilisation. The use of spectroscopic and structure-deter- mining techniques such as FTIR and LEED have provided estimates of the stretching of the C-C bond following chemisorption, either by: (i) a “n,~parameter” derived from the change in vibration frequency of the C-C bond, taking values between zero (for the free molecule) and unity (for CZH~B~Z)(24), or by (ii) a bond order between unity and two derived from the length of the C-C bond (19). Fig. 7 Molecular orbital diagrams jbr ethene Some values of both parameters are given in chemisorbed on metal surfaces:(a) the o-diadsorbed form on platinum, (b)the xoform on a platinum atom Table IV, and show that the distortion due to (the analogue of the structure shown in Fig. 6)and (c) stretchmg is shght for the Group 11 metals but large on atoms of Group 11, where back-bondingfrom ethene to metal cannot occur because of the lack of a suitable for iron, ruthenium, nickel and platinum surfaces. vacant orbital From the very extensive literature, the follow- ing generalisations may be made: by measurements of the equilibrium constant for (i) The 0-diadsorbed form of ethene is com- the formation of M(PR&(C2H4) complexes in ben- monly seen on platinum surfaces, but rarely on zene solution at 298 K: palladium, which usually shows the ~COtype of structure. M(PRJ3 + CzH4 + M(PR&(CzH4) + PR3 (ii) The JCG type occurs together with the 0-&ad- the values of which are - 300 for nickel, 0.013 for sorbed form on stepped platinum surfaces. palladium and 0.122 for platinum (20). Bond ener- (iii) Pre-adsorbed oxygen atoms favour the KG gies for these complexes and for those of the type form, or structures which tend towards this form. M(C0)4(C2H.,)have been calculated by relativistic The clear conclusion is that here is a marked
Platinwm Me:& Rm, 2000,44, (4) 152 tendency for ethene to be more strongly chemisorbed (as the 0-&adsorbed form) on plat- I Table IV inum than on palladium (where the nb form is Values of the 7c,o Parameter (24) and of the favoured); the parallels with coordination chem- C-C Bond Order (19) for Ethene Chemisorbed istry are also very marked, and the explanations are on Various Metal Surfaces the same. n,o Parameter Bond order
Other Alkenes Fe(ll0) 0.55 1.20 Ru(001 ) 0.85 1.35 Alkenes having a methylene group adjacent to Rh(ll1) 0.50 1.39 the double bond may on coordination lose a Ni(ll1) 0.80 1.33 hydrogen atom to form a n-allylic ligand (1, 2). Pd(ll1) 0.43 1.61 This occurs with a number of metal atoms and Pt(ll1) 0.92 1.13 Cu(100) 0.21 1.66 ions, but more readily and extensively with nickel Ag film - 1.88 and palladium than with platinum. Here is another Au foil 0.25 - distinction that may have its origin in relativistic effects. Dienes coordinate strongly through both double bonds to many metal species, for instance, is however not often noted. The distinction on palladium, 1,3-butadiene is chemisorbed by between the second and third row metals is strik- both double bonds in the mode, but on plat- ingly confirmed by inspecting, for example, inum, only through one double bond in the Number 3 of this Journal for 1999, where in the 0-diadsorbed form (18). reviews on pages 103 and 114, and in the Homogeneous Catalysis’ Abstracts and New Homogeneous and Heterogeneous Patents sections, every reference concerns either Catalysis of Reactions of ruthenium, rhodium or palladium. More generally, Unsaturated Hydrocarbons complexes of the three base metals: iron, cobalt It would be possible to summarise the homo- and nickel, are also effective, while those of the 5d geneous catalysis of alkene reactions and of metals and compounds of the Group 11 metals are metal-mediated reactions of organic molecules in not. This illustrates the operation of a “Volcano general by saying simply that (with the sole excep- Principle” in homogeneous catalysis: the 5d metals tion of hydrosilylation) all npin a metai m@owd or form complexes that are too strong, the Group 11 mvpkx dramjiom the ekmenfs in tbejnt & mnu .f metal complexes are too weak, while those of the Gm@ 8 to 10. This remarkably dear generalisation 3d and 4d metals fall in the acceptable range. Unfortunately there seems to be little pantit&be information available (apart from that mentioned Table 111 above) to underpin that statement. It is only necessary to record briefly some of Ethene-Metal Bond Dissociation Energies Calculated by Relativistic Density Functional the observations which lead to this concept. Early Theory (21)- work on homogeneous hydrogenation used com- pounds or complexes of iton, cobalt, ruthenium Complex Bond dissociation energy, kJ mol-’ and rhodium (for example, Wilkinson’s complex Rh(PPh3)sC1); hydroformylation used initially 38.0 cobalt, but this was later replaced by rhodium 19.8 which gave greater selectivity to terminal aldehy- 22.8 des (2). Complexes of Nin and Rh’ catalyse the 38.9 30.7 dimensation of alkenes (2), and complexes of Fen, 39.3 Ni” and Pdn with suitable nitrogen-containing hg- ands catalyse the polymerisation of ethene either
Platinwm Metub Rev., 2000,44, (4) 153 to a-alkenes or to high-density polyethene, diadsorbed intermediates with the B Group. Once dependq on the type of hgand (25). Nil' com- again there is a clear correspondence between the plexes also polymerise ethyne to either benzene or findings of organometallic chemistry and homoge- cyclo-octatetraene. neous catalysis and with those of heterogeneous In the case of hydrosilylation, the use of plat- catalysis. inum is probably required in order that an alkene The second point (ii) above also explains why complex of sufficiently great stability can be fat-hardening is conducted with nickel (27) or pal- formed in the presence of bulky -S& ligands. ladium (28) catalysts, but not with platinum. Alkenes coordinated to nickel and palladium Expressed briefly, a CI8 chain containing three species are susceptible to nucleophilic attack, for non-conjugated C=C bonds has to be hydrogenat- example by OH- ions. The best-known case of this ed so that only one C=C bond is left. This requires is the oxidation of ethene by Pd" to ethanal first an isomerisation to bring them into conjuga- (acetaldehyde), or in the presence of ethanoic tion, and then a selective hydrogenation, for which (acetic) acid to ethenyl ethanoate (vinyl acetate). nickel under hydrogen-diffusion-limited condi- Here the Pd' is reduced to Pdo, and an oxygen- tions is suitable. Palladium is also suitable. carrying Cu" species is needed to complete the We may also note that ethyne trimerises to ben- catalytic cycle (1, 2). zene on palladium (best on the (111) surface), just In heterogeneous catalysis, the clearest proof of as occurs with Ni" complexes (29). the operation of a relativistic effect lies in the reac- Finally we may ask why platinum was the metal tions of unsaturated hydrocarbons with hydrogen of choice for petroleum reforming, since the open- or deuterium. There is a very clear distinction ing step is dehydrogenation of an alkane, followed between: by desorption of an alkene and its migration to an (A) nickel and palladium (and copper) on the one acid site. In fact nickel was the metal first used, and hand, and recently palladium has found some use, so the (B) platinum (and iridium) on the other, in the answer probably lies in the fact that platinum, in following reactions (26): conjunction with tin or rhenium, is much less sus- (i) Reaction of ethene with deuterium, where the ceptible to deactivation by carbon deposition than A Group metals allow a much greater return of nickel or palladium would be. deuterium-substituted alkenes to the gas phase. (ii) Reactions of Cq or hgher alkenes where mol- Some Final Thoughts ecules altered by double-bond migration or This review has indicated that there are many E/Z-isomerisation appear in the gas phase to a respects in which the 5dmetals (Os, Ir, Pt, Au) dif- much greater extent with the A Group than the B fer from the 3d base metals (Fe, Co, Ni, Cu) and Group. the 4d metals (Ru, Rh, Pd, Ag) (30). These differ- (iii) Hydrogenation of alkynes and alkadienes, for ences can be explained in terms of the stabilisation which the A Group metals are more active, and on of the 6s level and the destabilisation of the 5d which they afford the intermediate alkene with level, compared to the situation in the earlier series, much %her selectivity, and preferential Z-addi- see Figure 2. The origin of this phenomenon is the tion of hydrogen; with 1,3-butadiene, for example, operation of a relativistic effect on all the s orbitals. a high yield of 1-butene is obtained. Metal catalysts for those reactions involving only All of these observations are consistent with a o-bonded akyl radicals or multiple C=M bonds weaker chemisorption of the alkene compared to (equilibration of alkanes with deuterium, alkane that of the akyne or alkadiene on the A Group hydrogenolysis, etc.) do not show preferential metals, as indeed was suspected many years ago activity related to this effect. (26). These and other features of the reaction have It may be wondered what other aspects of the been rationalised by proposing that n(3 or x-allylic chemistry of the elements may be traced to this intermediates occur with the A Group, but (3- cause. In the bioinorganic field, there is platinosis,
Phtinnm Metah Rm,2000, 44, (4) 154 but not palladosis; there is the well-known toxicity 12 A. Sandell, P. Bennich, A. Nilsson, B. Hemnas, 0. of many of the heavy elements, but the beneficial Bjomeholm and N. Mirtenson, S~tlfSci, 1994,310, 16 use of platinum complexes in chemotherapy (7) 13 P. Dumas, R G. Tobin and P. L. Richards, Su$ SCi.., (but not so much those of palladium or other met- 1986,171,555,579 als) and of gold (but not silver) in treating arthritis. 14 G. Paccioni, S.-C. Chung, S. Kruger and N. Rosch, Sutlf Sci., 1997,392.173 It would be surprising if there were not some 15 J. Li, R M. Dickson and T. Ziegler, J. Am. Cbm. underlying connection. SOC.,1995,117,11482 So next time you touch gold, or drive a car with 16 B.-J. Deelman, Phtinum Metals Rev., 1999, 43, (3), a platinum catalyst beneath it, or take your tem- 105;J. H.Jones, ibid., 2000,44, (3), 94 N. Sheppard and C. De la Cruz, 4.Cutal., perature with a mercury-in-glass thermometer do 17 1996, 41,l;ibid., 1998,42,181 remember: you are now directly in touch with 18 F. Zaera, Cbm. Rev., 1995,95,2651 some consequences of the principles that shape 19 E. Yagaski and R Masel, in “Specialist Periodical the Universe and are determining its evolution. Reports: Catalysis”, Roy. SOC. Chem., London, 1994, Vol. 11, p. 164 References 20 C. A. Tolman, W. C. Seidel and G. H. Gerlach, 1. Am. Cbem. SOC.,1972,94,2669 1 N. N. Greenwood and A. Eamshaw, “Chemistry of the ~~~~~~77,znd E&., B~~~~~~.H~~~~, 21 J. Li G. Schmkenbach and T. Ueder, znq. Chm., Oxford, 1997 1995,34,3245 G. Bond, Di.sms. Farday SOC., 2 F. A. Cotton and G. Willtinson, “Advanced 22 C. 1966, 41, 200; Phtintm Metub Rev., Inorganic Chemistry”, 5th Edn., Wiley-Interscience, 1966,10,(3), 87 New York, 1988 23 A. M. Bradshaw, Sn$ Sd, 1995,331-333.978 3 G. C. Bond and D. Thompson, Catal. h.:Sci. Eng., 24 E. M- SmVe and R.J. PbCbem., 1985,89, 1999.41.319.. 105,3183 4 D. C. Hoffinann and D. M. Lee, J. Cbm. E&c., 25 V. Gibson and D. Wass, Cbem. Br., 1999,35,(7), 20 1999,?6,332 26 G. C. Bond and P. B. Wells, Adv. Catd., 1964,15,92 5 K. S. Pitzer, Acc. Cbem. Res., 1979,12,271 27 G. C. Bond, “Heterogeneous Catalysis - Principles 6 P. Pyykko and J.-P. Desclaux, Acc. Cbm. Res., 1979, and Applications”, 2nd Edn., OW, Oxford, 1987 12,276 28 V. I. Savchenko and I. A, Makaryaa, Phtinum Metals 7 P. Pyykko, Cbem. Rev., 1988, 88,563 Rm, 1999,43, (2), 74 M. Gentle and E. L. Muetterties,J. Cbem., 8 P. Chini, G. Longoni and V. G. Albans, Adu. 29 T. P4.r. Orpnomet. Cbcm., (eds. F. G. A. Stone and R West), 1983, 87,2469 1976,14,285 30 G. C. Bond, J. Mol. Catal. A: Cbem., 2000,156,l 9 E. P. Kiindg, M. Moskovits and G. A. Oh,Can. J. Cbm., 1972,50,3587 The Author Geoffrey Bond has retired from Brunet University and is Emeritus 10 J. Li, G. Schreckenbach and T. Ziegle, j. Am. Cbem. Professor. He is also Visiting Professor at the University of Salford. Soc., 1995, 117, 486 His major interests are in metal-catalysed reactions of hydrocarbons, 11 K. Duckers and P. Bonzel, Sutlf Sci., 1989,213,25 supported oxides and kinetics of catalysed reactions. Platinum Films in Gasochromic Switched ‘Smart’ Windows The solar hght and heat allowed into a buildmg ods: to make wo3 film, with platinum catalyst can be controlled by W0,film ‘smart’windows. sputtered on the surface and atomic hydrogen Optical modulation is used to ‘switch’ such films (gasochromism) to ‘switch‘ them (U. Opara to control the frequencies transmitted. Switchmg Kraiovec, B. Orel, A. Georg and V. Wittwer, Sohr can be done in different ways. WO3 films prepared Enw, 2000,68, (6), 541-551). by sputtering have fast colouring/bleaching bet- Sol-gel W03 films were made by dip-coating. ics, but textured surfaces. Sol-gel-made films have Adding an ormosil gave thicker, less bride films higher visible transmittance in the bleached state of improved coloration. The sol-gel/Pt(sput- and thicker films are easier to make. tered)WO3 films change colour as quickly as Now work from the National Institute of Pt/WO3 sputtered hlms, and faster than wo3 sol- Chemistry, Ljubljana, Slovenia, and the Fraunhofer gel hlms with Pd. In H2/Ar gas mixtures the films Institute for Solar Energy Systems, Freiburg, colour in HZconcentrations as low as 0.002 pe-r cent. Germany, combines sputtering and sol-gel meth- This may give simpler switchable ‘smart’windows.
Phiinurn Metah b.,ZOOO, 44, (4) 155 Jewellery Manufacturing Technology LATEST ADVANCES REPORTED AT THE FOURTEENTH ANNUAL SANTA FE SYMPOSIUM
The 14th Santa Fe Symposium on jewellery man- but has not seen commercial application. Its use ufacturing technology was held in Albuquerque, for the production of wedding rings in carat golds New Mexico, from 21 st to 24th May 2000 and this and platinum was described by P. Raw (Consultant year attracted a record 188 delegates from 19 coun- to Engelhard-CLAL, U.K.). Based on a press and tries. Twenty-five presentations on the latest sinter technique using water atomised powders, the research results and advances in technology cov- process not only leads to better technical proper- ered all the precious metals and gems, with ties, such as smaller grain size and increased platinum jewellery receiving considerable attention ductility (facilitatinga hgher degree of ring sizing), - as it has over recent years - and illustrating the but it is also faster and has hgher productivity, and considerable interest in this fashionable jewellery hence it is more economic. This process is a major metal. breakthrough and is already attracting attention The Symposium opened with Mark Grimwade from other jewellery fabricators. (Consultant, U.K.) giving his now customary The elecaoplating of the platinum group met- ‘Introduction to Metallurgy & Jewellery Alloys’ als: platinum, palladium and rhodium, for lecture, which this year was widened to include a decorative and functional applications was detailed section on platinum jewellery alloys. This reviewed by E. Salomon (Consultant, Technic Inc., was followed by John Wright (Consultant, U.K.) U.S.A.), with many practical tips for the small elec- talking about ‘Mechanical Properties and troplater. Rhodium, of course, finds application on Jewellery’, which gave an insight into how such white gold jewellery to improve colour. properties impact on manufacturing processes and The rapid production of platinum jewellery in the design of jewellery from an engineering per- the small workshop by high speed investment cast- spective. The advantages to fabricators of the ing (lost wax casting) was described by Jurgen unique properties of platinum in jewellery manu- Maerz (Platinum Guild International). Using mag- facture were highlighted. nesia-based dental investments, which can be fired The unusual macwproperties of platinum quickly, it is possible to make a successful casting have been the subject of much investigation, see in less than 2 hours. This will prove to be a boon (1) for example. More recently, new work to opti- to the designer/smith making individual pieces to mise machining parameters for surface quality has order. Modem investment casting of jewellery was been undertaken by C. Volpe (Tiffany & Co.) and origmally developed from the dental industry tech- R Lanam (Engelhard-CLAL) and their initial nology in the 1950s. This work once again results on platinum-5 per cent ruthenium alloy illustrates how technology has been successfully were presented at Santa Fe last year. The second transferred across into the jewellery sector. part of their results, presented at this Symposium, On the broader precious metal jewellery front, extended their earlier work to other platinum jew- a number of papers were presented on aspects of ellery alloys includmg a new age-hardenable 950 jewellery technology. R. Carter (Ransom & platinum alloy. Surface quality was evaluated by Randolph, U.S.A.) described the effect of water surface roughness measurements and by examina- quality and temperature on investments for lost tion under a scanning electron microscope, and wax casting of precious metals. The use of de- results showed polycrystaJline diamond tools to be ionised water to maintain a consistent quality was superior to cermet tools. The best surface texture recommended. New research into the thermal sta- was found on the age-hardenable alloy. bility of investments was also reported by G. M. Powder metallurgy as a process for producing Ingo (CNR, Italy). The stability of investments is precious metal jewellery has long been attractive, important to the lost wax casting of jewellery.
PhtinwnMetals Rev., 2000,44, (4), 156157 156 Instability is often a cause of a number of casting mance and aaining evaluation was discussed. defects including gas porosity; progress is being Other presentations looked at copyright and achieved in improving stability. patent law, quality assurance and at the metallurgy The influence of the metallurgy and chemistry and properties of other precious metals. of jewellery materials on the processes used in jew- The presentations at this Santa Fe Symposium elleiy manufacture was discussed by D. Ott (FEM, and previous Symposia are available from: The Germany). This topic was also picked up by H. Santa Fe Symposium, 7500 Bluewater Road NW, Freye (Techform, U.S.A.) in considering the NM 87121, U.S.A. Tel: +1 505 839 3249; Fax: +1 ceramics used in shell casting of high temperature 505 839 3248; E-mail: [email protected]. alloys includulg platinum. C. W. CORTl G. Normandeau described the metallurgical References training programmes used by his company, 1 R W. E. Rushforth, P/atinlrm Metah Rcu., 1978, 22, Imperial Smelting & Refining Ltd., Canada. This (119 2 includes subject matter unique to platinum as well The Author Chris Corti is editor of Gold Bulletin and Gold Technology. His main as gold and silver. All staff on the shop floor are interests are the manufacturing technology of gold jewellery and the trained and the impact of this on staff perfor- industrial applications for that metal. High Breakdown Voltage of Au/Pt/GaN Schottky Diodes In power electronics (power > 1 MW), silicon merit (Vrn)'/RON,(hN = on-state resistance) were carbide, +um arsenide and +um nimde (GaN) 4.2 to 4.8 MW crn-'. The reverse leakage currents are being developed as alternative materials to sili- and forward on-voltages were shghdy higher than con. Silicon carbide is already used in solid-state theoretical minimum values, but comparable with power electronic devices, such as diodes, thyristors reported Sic Schottky rectifiers. The GaN-devices and transistors. Wide bandgap GaN, with hlgh show promise for use in ultralugh-power switches. breakdown voltage, is also under extensive invesd- gation for power device uses, but little work has Damping in Ruthenium Alloys been reported on breakdown in GaN diode devices. An important physical property of an alloy is its Schottky diodes can switch faster than junction damping capacity in response to an imparted diodes and are often used to measure the quality of mechanical force. High damping in iron-rutheni- material. Now, a team of researchers, from the um alloys is closely linked to the amount of E National Central University, Taiwan, the martensite present. University of Florida, Sandia National Scientists at Yonsei University, Seoul, Korea, Laboratories, Bell Laboratories, and a consultant, have investigated the damping capacity of iron- U.S.A., have examined breakdown using ruthenium alloys, containing 25 and 13 per cent Ru Au/Pt/GaN Schottky diode rectifiers (G. T. Dang, at room temperature, using samples processed to A. P. Zhang, M. M. Mshewa, F. Ren, J.-I. Chyi, C.- contain various amounts of E martensite (H.-C. M. Lee, C. C. Chuo, G. C. Chi, J. Han, S. N. G. Shin, J.-H. Jun and C.3. Choi, Sm. Muter., 2000,42, Chu, R G. Wilson, X A. Cao and S. J. Pearto&]. (lo), 981-986). VM.Sci. Technol. A, 2000,18, (4), 1135-1 143). Fe-13% Ru, which undergoes a y+a' marten- GaN was grown by MOCVD on sapphire via site transformation to give a' Mephase, showed NH, and trimethylgalhum precursors. The ohmic poor damping capacity. Fe-25% Ru undergoes a contacts were formed by Pt/Au liftoff. They were Y+E martensite transformation and has hlgh damp- annealed before Pt/Au deposition. Optimised high- ing capacity, dependent on the strain amplitude. density plasma etchmg conditions were developed For Fe-25% Ru, damping capacity increases with for GaN, to give minimal degradation in reverse increasing E martensite content at < 3 xIO" strain current leakage in pi-ti mesa diodes. Reverse amplitude. At strain amplitude > 4 x104 it reached breakdown voltages (V,) of up to 550 V on verti- a peak for a volume fraction of - 42 per cent of & cally depleting structures and > 2000 V on lateral martensite. Stackmg fault boundaries inside the E devices were obtained. Values for the figure-of- martensite plates act as damping sources.
Pkatinum Metah Rex, 2000,44, (4) 157 Platinum Me tals-B as ed Inter metahc s for High-Temperature Service
By Ira M. Wolff and Patricia J. Hill Physical Metallurgy Division, Mintek, Private Bag X3015, Randburg, 2125 South Africa
Not long ago structural intermetallics were metallurgical curiosities rather than the,focus of a serious campaign to topple the supremacy of nickel-based .sriperalloys. Indeed, a handful of intermetallic compounds, notably the titanium and nickel aluniinides, have succeeded in making it to the point of operational testing: but, if anything, they have highlighted the challenges facing a new generation of ultra-high temperature materials. Two constraints in particular have directed developments. First, at the core of the development of intermetallics, is the need to address the dual requirements of low-temperature toughness and high-temperature strength central to structural applications. Second, the operating conditions of interest (temperatures above Il5OoC)call for a marked improvement in the environmental resistance of the materials. In these respects, systems based on platinum group metals deserve attention. The potential benefits resulting from using composite microstructures based on platinum, iridium and ruthenium are highlighted here, using collaborative studies being undertaken by Mintek and a number of alloy development centres.
The attributes that make intermetallic higher melting points, based on Ll2 precipitates compounds desirable materials for hgh-tempera- (ordered f.c.c.) in a f.c.c. matrix (the matrix usually ture structural applications have been widely has the higher melting point) are however limited reported (1). Intermetallics draw on properties in number. Some of the platinum group metals are such as good diffusional creep resistance, almost unique among the high-melting-point met- hgh-temperature strength, high melting points, als in that they have f.c.c. structures. Moreover, good oxidation resistance and low densities for they have environmental resistance that enables performance in service regimes which the nickel- them to be considered for higher-temperature use. based (Ni) superalloys cannot meet. Unfortunately, Systems based on iridium Qr), rhodium (Rh) and their almost-universal low tolerance to defects platinum (Pt) have attracted attention that has led makes them unsuitable for application in critical to the suggestion that they form a class of alloys to components. Engineering design and alloy devel- be named ‘refractory superalloys’ (2). (This term- opment therefore have to address the competing nology is something of a misnomer insofar as requirements for high-temperature strength and refractory metals are normally associated with ambient-temperature toughness. This has led to strong aftinities for oxygen, whereas most of the the interest in multi-phase systems which bring platinum metals are relatively noble in this respect). together these apparently contradictory attributes. Second, analogous precipitation-strengthened Three such approaches are currently under investi- systems have similarly been proposed for the b.c.c. gation. metals, in this case with an ordered b.c.c. structure In the first instance, the success of the Ni-based contained within a ductile b.c.c. matrix (or p/p’). superalloys leads one to seek succeeding genera- Among the most oxidation resistant of materials tions of high-temperature alloys that make use of are ferriuc alloys based on iron-chromium-alu- the precepts of a high volume fraction of minim (Fe-Cr-Al), typically with composition finely-dispersed, coherent precipitates within a around 20 wt.% Cr and 5 wt.% Al. Various ductile matrix. Analogous y/f systems with much attempts at alloying have been made to induce the
Phtinnm Metah Rm, 2000,44, (4), 15a166 158 precipitation of coherent precipitates in these systems, and one such study examines alloying with ruthenium (Ru) to enhance not only the strength, but also the oxidation and corrosion resistance of these alloys. Third, there are the so-called in sirw com- posite microstructures, which exploit ‘ductile phase toughening’. Methods to pro- duce ductile phase toughening stem fiom the recognition that ‘ductile’ secondary phases contribute not only towards deflect- ing crack propagation in the usual way, but also to strengthening (by acting as obstacles to dislocation motion at the phase inter- faces). In particular, eutectic systems lend themselves to exploitation of inherently compatible phases in a finely divided mix,
and are natural candidates for structural I intermetallic composites. Some eutectic 500 1000 1500 21 I systems, based on Ru-Al, Ir-Al, Ru-Nb TEMPERATURE, *C (niobium), Ir-Nb, Ru-Al-Ni and Ru-Al-Ir, Fig. 1 The high-temperature compression strength of some have been examined (3-5). The systems are iridium-based alloys: Mar-M247 is a nickel-based superalloy, unusual because although the ducdities of CMSX-10 is a single crystal nickel-based superalloy (2) Ru and Ir, in elemental form, are unprepos- sessing, some of the ordered phases are uniquely small lattice mismatches, develop microstructures ductile within the context of intermetallics. and mechanical responses strongly reminiscent of In this paper hghhghts of some of the current the Ni-based systems. The extraordinary mechani- research are reported. Concepts are discussed cal performance of these alloys indicates that there more fully elsewhere in a publication which traces could possibly be a supersedmg class of super- the emerging role of the platinum metals in coat- alloys, see Figure 1. ings, superalloys, structural intermetallics, and as a For a number of reasons, development studies potential basis for an entirely new generation of on Ir-based superalloys have been extended to materials for high-temperature applications (6). examine their convergence with Ni-based superal- loys by cross-alloying (7, 8). Although attractive The ‘Refractory’ Superalloys mechanically, the simple Ir binary systems have a Compression tests on Ir-Irab (Ir-15 at.% Nb) number of drawbadrs: a hgh density, restricted have ranked this system and the related Ir-X and room-temperature ductility, relatively poor hgh- Rh-X alloys Q = hafnium (Hf),zirconium (Zr), temperature oxidation resistance (Ir forms volatile tantalum @a), titanium pi) or vanadium 0)as oxides above 1196”C), and, perhaps most signifi- being among the strongest of all metallic materials cantly, the limited physical supply of Ir in the ever tested at temperatures up to 1800°C (2). At world. Only some 4 tonnes of Ir are produced the heart of these simple binary alloy systems lies anndy to meet the already hgh demand by a the classic coherent y/v microstructure, but with variety of industrial applications. World Ir (and the advantages of a hgher melting point and the Rh) resources would be unable to sustain a major inherently htgher critically resolved shear stress new bulk application, and these alloys must that Ir has over Ni. The strongly ordered Llt pre- inevitably find use in only the most performance- cipitates, with distinctive morphologies and very critical and niche applications.
Phtinxm Metuh Rm, 2000, 44, (4) 159 Ptx2 A114Tir P~~~AIZ~RU~ Prd1lICn Fig. 2 Oxidation structures of Pt-Al-X alloys, exposed at 1200°C for 500 hours. Additions of Ti, Ru and Cr support the development of adherent protective scales. while Re and Ta increase the propensity for internal oxidation (14)
Platinum, on the other hand, enjoys relative protective scale-forming mechanisms or coatings. abundance and excellent environmental resistance. Most of the refractory additions to platinum great- Although it has a more modest melting point ly debilitate its environmental resistance, leading to (1772°C) than Ir, a Pt solid solution can be equili- severe internal oxidation in the absence of such a brated with an L12 phase in a number of systems. protective mechanism. In particular, useful high temperature L11 com- In this respect, the Pt-Al system holds great pounds are derived by alloying with Al, Ti, Hf and promise, having a considerable history as a protec- Zr. With other elements, systems which are stable tive coating on Ni-based superalloys (12). Platinum at lower temperatures are formed, for example: aluminides represent some of the most adherent, Pt3Cr, Pt3Ga, Pt&, Ptw, PtjSn, PtZn and oxidation- and hot corrosion-resistant formula- Pt3Co. In certain Pt,X systems, for example Pt;V, tions identified to date. Studies of the Pt-A1 system Ptab and Pt3Ta,X may not form an L12 structure have shown that as little as 2 wt.% of Al in Pt is with Pt at low, or, in other cases, any temperatures, sufficient to establish a thin protective oxide coat- but may be stabilise an Llz phase (as in fact they do ing at temperatures up to 1450°C (13). However, in the Ni-based alloys) in combination with other even relatively small additions (several per cent by elements. weight) of strong oxide-forming elements can be Intermetallic dispersion-strengthened alloys inimical to the oxidation resistance of the Pt-Al based on Pt-Hf and Pt-Zr have also been proposed alloys, and it has been found that the protective (9). These have promising melting points and some scale-forming ability is initially compromised at of the phase relationships have been reported (10). elevated temperatures when elements, such as Re More recently, Hill and colleagues have evaluated and Ta, are present, see Figure 2 (14). microstructural development with other additions The microstructure of the Pt-PtAl system, as to Pt, notably Al, rhenium (Re), Ta, Nb, Ti, Ru and developed by solutionising and ageing, is shown in Ni (11). In the course of this work, it became clear Figure 3. Among its principal features are: that the high-temperature stability of these systems strongly oriented cuboidal precipitates, typically in oxidising atmospheres will have to rely on present in a bimodal size distribution. The
Phtinwn Metah Rev., 2000,44,(4) 160 Fig. 3 Cuboidal PtrAI precipitates in Pt8zAlr2,which has been solutionised and aged at 1350°C. Evidence of a sub-micron secondary precipitate structure can be seen interspersed with the cuboids
microstructure finds strong con- nection with the Ni-Nia system in terms of morphology and development (see, for deformation is generally thought to be the limiting example, Westbrook (15)). The distinctive factor in increasing mechanical strength (18). cuboidal geometry is taken to indicate low mis- These features are being addressed by ternary match strain and a hgh degree of coherency. and higher order alloying additions, aimed at: the existence of a low-temperature variant of (a) moderating the lattice mismatch between the the Pta?/ phase, manifested by a lath or twinned two phases for optimal stability in the temperature microstructure. This is problematic in the sense range of interest that microstructural stability and dimensional tol- @) stabilising the high-temperature Llz phase erances can be compromised during service. down to room temperature a relatively low volume fraction of the precipi- (c) maximising the volume fraction of the f tated ?/ phase, dictated by the maximum solubility phase, and point of Al in the Pt solid solution. (d) increasing the resistance of the matrix phase to the Ptaphase has been shown to have greater deformation - by solid-solution strengthening. strength in compression than its Irab counter- Systems based on the Pt-AI-X ternaries have part at temperatures up to about 1000°C (16,17), come in for most attention at Mintek (19). Simple but the disordered platinum solid solution lacks ternary formulations have been tested in compres- the hlgh critical resolved shear stress (CRSS)of It. sion at temperatures up to 1350”C,see Figure 4, As in the case of the Ni-based superalloys, the and found to outperform their conventional resistance offered by the solid-solution phase to
------t Ft-Al-Ru - Mar-M247 PM2000
Fig. 4 High-temperature compression strength of Pt-Al-Ru ’)f/f alloy compared to that reported for Mar-M247 (a Ni-based superalloy) and the tensile strength of PM2000 (an TEMPERATURE, ‘C Fe-based superalloy) (19)
Pkztinam Mefab Rm, 2000,44, (4) 161 Fig. 5 Isothermtrl oxidation hehaviour of Pt-Al-Cr arid Pt-Al-Ru y/y alloys at 1350°C compared to that reported for PM2000 (an Fe-based superalloy) at 1300°C. The ht’o Pt alloys show ideal para-linear behaviou6 as opposed to the mass loss shonvi by PMZOOO ( 14)
-6.1
-8 0 50 XX, 150 200 250 300 350 400 TIME, hours
Ni-based counterparts (these, of course, are limit- been found to enhance greatly both the lugh- ed by their melting point at these extremes of temperature oxidation and aqueous corrosion temperature) (20). Static oxidation trials point to resistance of these alloys (26). This leads to the the considerable efficacy of the aluminium in pro- idea that these alloys might similarly be strew- vidmg a protective adherent scale on the Pt-A- ened by a precipitated RuAl (B2) phase if such a based alloys (14). In this regard the Pt-based phase could be induced at hgher alloying levels of systems have also proved to be capable of with- Ru. RuAl precipitates would have the benefit of a standing greater extremes of temperature than hgher melting point and possibly greater stability their base metal counterparts, based on their than the isostructural NiAl phases. higher melting points, see Figure 5. In a recent study, up to 4 wt.% Ru was added to alloys based on Fe-35Cr-5Al and Fe-20Cr-5A (27). Ferritic Alloys with Platinum Metals In addition to the alloys being soluiion-strength- The concept of a b.c.c. ‘superalloy’ analogue is ened by the Ru, the resulting alloys also exhibited not new, and coherent precipitation-strengthened characteristic age-hardening behaviour in response p/p’ alloys have been widely investigated. A pop- to isothermal annealing at up to 850°C. This can be ular approach has been to cultivate NiAl-type (B2) correlated with the development of a fine predpi- precipitates in a ferritic @.c.c.) matrix, and precip- tate distribution, see Figure 6. Strong wentof itation-strengthened alloys: Fe-Cu-Au (gold) (21), the precipitates and associated strain fields indicate Fe-Ni-Al (22), Fe-Ni-Al-Mo (molybdenum) (23) that there is at least partial coherency with the and Fe-Cr-Al-Ni (24, 25) have been described. matrix. Despite significant increases in strength at low to Unfortunately the precipitates appear to have intermediate temperatures, rapid coarsening of the no advantage over their NiAl-type counterparts in precipitates is reported to occur at temperatures terms of their resistance to coarsening. This can be much above 700°C. The stability of the precipitates understood from an analysis of the precipitates. has been found to decrease as both the lattice mis- Although too fine to isolate, analysis by match, and the volume fraction of the precipitates, TEM-EDS points to Al-rich stoichiometries closer increase (23). to 21 or 3:1, which would indicate one of the Ferritic alloys based on the Fe-Cr-A system lower aluminides had formed, such as R&, have exceptional oxidation resistance and find which would at best probably be only semi-coher- widespread application in turbine seals, catalytic ent with the matrix. Ru:A alloying ratios converter substrates, and heating elements. considerably closer to 1:l stoichiometry thus Microalloying additions of Ru (- 0.2 wt.%) have appear to be required in order to stabilise the RuAl
PhhHm Metah Rev., 2000,44, (4) 162 Fig. 6 Age-hardening in alloy iron-chromium- uluminium-ruthenium (Fe-35Cr-SAI- Ru) - lwt.%Ru (a)Ageing behaviour at - 2wt.V. Ru 700°C as a function of the amount of ruthenium (b)Development of a semi-coherent precipitate structure, within the alloy Fe-35Cr-5Al-IRu, showing strong crystallographic alignment and associated strain fields (27. 28)
'""1 , 1. 0 0.33 0.67 1 2 3 5 7 9 11 14 18 TIME, hours symmetry. Lowering the Al content while main- taining Ru levels of about 4 *.%, however, does not appear to effect any precipitation hardening (28). The patent literature indicates that Ru con- tents of between 18 and 30 wt.?! are necessary to stabilise the RuAl phase in these systems (29).
Eutectic Ru-RuAl and Ir-IrAl Alloys Considerable interest was evoked by R L. Fleischer and colleagues (30, 31) in a handful of platinum metals-based intermetallic compounds which display useful room-temperature toughness: notably RuTa &lo),IrNb &lo), RSc (B2) and RuAl Q32). While factors like poor oxidation resis- tance and scarcity limit the first three in by changing the operative fiacture and deforma- applications, the development effort put into RuAl tion processes at the phase interfaces (34). has been sustained by its singular combination of Effectively, this same compliant-layer effect is hgh melting point (- 2O5O0C), thermodynamic reproduced on the micrometer level in the eutectic stability, toughness, corrosion resistance, thermal which forms as a fine mix of Ru-RuAl lamellar and electric transport properties, oxidation resis- plates, and yields a ductile phase composite. The tance and amenability to substitutional alloying synergy of the constituent phases of the Ru-RuAl (32, 33). eutectic in evolving strengths far greater than One of the development paths followed for the those anticipated from simple rules of mixture is production of RuAl takes as its starting point the demonstrated in Figure 7 for a composition cho- two-phase mixture that can be equilibrated sen to be primarily eutectic in microstructure. between the B2 RuAl and the Ruh,,-RuAl eutec- The benefit to be gained from such a fine tic. In melt-processed material, Ru-rich eutectic mix can be extended to ternary alloys, stoichiometriesresult in the formation, of an inter- such as those based on Ru-Ni-Al. These can be granular phase (eutectic) which has the attributes formulated to give mixed eutectic structures with of a compliant layer. This intergranular phase substantially h.gher strengths than the simple greatly enhances the ductility in alloy formulations Ru-RuAl binary (3). The close resemblance of the which mainly comprise the B2 RuAl-type phase, Ir-Al system to the Ru-AI system allows the even
PL#rn Mctalr Rn?, 2000,44, (4) 163 Fig. 7 High-temperature conipression strength of ' .-- I eutectic Ru-RuAI RU-RuAI (Melt) (Ru7,rAl,,)in relation to its constituent phuses of Ru IP l2*I1000 mid RuAI (4. 6)
I 200 400 600 800 1000 1200 1 3 TEMPERATURE, *C hlgher melting points and strengths of Ir and IrAl melt with refractories, volatility of aluminium, to be exploited in a similar way (4). inhomogeneous solidification), recourse to powder Despite the excellent extrinsic toughening and metallurgical techniques allows the development strengthening characteristics of the lamellar struc- of near full-density material with unique ture (typically - 0.7-0.8 pinterlamellar spacing), microstructures. One such example is shown in there is a limit to the gains achievable in hgh-tem- Figure 8. Here, a homogeneous distribution of a perature strength. At a temperature roughly half secondary phase (in this case the eutectic con- the melting point of the alloys, strength tails off stituents) can be engineered, to give rise to a significantly as interfacial sliding becomes prob- precipitation- or dispersion-strengthened RIA. lematic. An alternative approach is therefore to The accompanying improvement in resistance to effect a fine discrete dispersion of the eutectic high-temperature deformation is illustrated in phases to limit the operative distances for sliding. Figure 7. The production of RuAl-based mated by reactive hot isostatic pressing (RHIP) offers a useful way in Conclusion which such a microstructure can be engineered The development of composite microstructures (33, 35). based on platinum metals intermetallics is still in its While conventional melt processing techniques infancy, but these alloy classes provide ample are subject to various limitations (reactivity of the opportunities for next-generation ultra-high
Fig. 8 Microstructure of eutectic Ru-RuAl created by reactive hot isostatic pressing (RHIP) (33). The microstructure is characterised by a fine. discrete dispersion of the eutectic phase
Pbtinwm Met.& h.,2000,44, (4) 164 temperature materials. Three classes of materials to holdmg the metal plus the recychg cost. based on platinum metals have been hghhghted Perhaps two more serious constraints worth fac- here, these being alloys developed in the superal- toring in are: (1) the limited physical supply of loy paradigm, augmented femtic alloys, and certain platinum metals (notably Ir and Rh) to composite alloys. The unparalleled combination of industry, which precludes their use in large-scale environmental resistance, high melting point and bulk applications, and (2) the entry into a new tem- crystal structure make these platinum metals-based perature regime with regard to primary intermetallics sound contenders for applications in manufacture and processing. Process metallurgy performance-critical components. has lagged behind alloy development, and hgh- In a previous publication, R L. Fleischer spec- volume component production of these ulated on platinum metals-based intermetallic h@-melting point compounds has some way to compounds in turbines, and noted that their cost travel before it becomes an industrial reality. is likely to preclude them in the near future (30). It is, however, a common maxim that any gains in Acknowledgements the operational parameters of aerospace materials, The results reported here ace drawn from a wide-ranging be it strength, temperature or service interval, research programme, and the authors are particularly indebted eventually get adopted in the relentless push up to the following collaborators: Dr G. Sauthoff (Max-Planck- Institut her Eisenforschung, Germany), Professor C. the performance meof high-temperature mate- Humphreys (Rolls Royce University Technology Centre, rials. Cost can be significantly discounted when it Cambridge, U.K.) and Dr H. Harada and Dr Y. Yamabe-Mitarai is appreciated that precious metals invariably (National Research Institute for Metals, Japan). Financial sup- port from the Department of Arts, Culture, Science and re-enter the secondary market by means of rev- Technology, South Africa and the Platinum Development *,and the real cost is only the interest lost due Initiative is gratefully ahowledged.
References
“Intermetallic Compounds - Principles and 9 G. B. Fairbank, C. L. Humphreys, A. Kelly and C. Practice”, eds. J. H. Westbrook and R L. fleischer, N. Jones, Conf. Proc. Intermetallics for the Third John Wiley and Sons, Chichester, 1995 Millennium, ASM, Cincinnati, lst-4th Nov., 1999 Y. Yamabe-Mitarai,Y. Ro, T. Maruko, T. Yokokawa 10 G. B. Fairbank, C. L. Humphreys, A. Kelly and C. and H. Harada, ‘Platinum Group Metals-Base N. Jones, lvew Platinum Alloys for Ultra-High Refractory Superalloys for Ultra-High Temperature Temperature Applications’, presented at the 5th Use’, Stnutnml IntmnckrllicJ 1997, (Proc. 2nd Int Charles Parsons Turbine Conf., Cambdge, U.K, Symp. on Structural Intermetallics, Seven Springs, 3rd-7th July, 2000 chmPi04 U.SA., eds. M. v. NawDaioh c. 11 P. J. W, T. Biggs, P. Ellis, S. Taylor and I. M. Wolff, T. Liu, P. L. Martin, D. B. Miracle, R Wagner and ‘An Assessment of Ternary Precipitation- M. Yamaguchi, Minerals, Metals & Materials SOC., Strengthened Platinum Alloys for Ultra-High 21st-26th Sept., 1997, pp. 805-814) Temperature Applications’, U.Sci. Eng., in press 1. M. Wolffand G. sauthoff, Metau. Muter Tm.4 12 “coatings for mh-Temperature ~~~~~d 1996,274 1395 Materials’’, National Research Council, National 1. M. Wolffand G. sauthoff, hf8ta.Z Me.Tm. 4 Academy Press, Washington, D.C., 1996 1996,274 2642 13 E. J. Felten and F. S. Pettit, Oxid Met., 1976,10, (3). P. J. HI& L. A. Cornish and M. J. Witcomb,]. A,!Iqs 189 Coqba!, 1999,291,30 14 P. L. Hill, P. Ellis, P. L. A. Cornish, M. J. Witcomb I. M. Wolff, ‘Precious-Metal Intermetallic and 1. M. woEf, me &&tion Behaviour of Compounds’, in ‘‘Intermetallic Compounds - Pt-4-X Alloys at Temperatures between 1200 and Principles and Practice”, Vol. 3, eds. J. H. 135~~, at c~igh-~~~~~~~como~on Westbrook and R L. Heischef, John W~Vand and Protection 2000’, Japan, 17th-ad Sqt,2000 Sons, Chichester,in press 15 J. H. Westbrook, Z. Krirhhg., 1958,110,21 X H. Yq Y. Yamabe-Mitarai, Y. Ro and H. Harada, Metau. M&. Tram. A, 2000,3lA, 173 16 D.-M. Wee, 0. Noguchi Y. Oya and T. Suzuki, Tm.JIM, 1980,21,237 X H. Yu, Y. Yamabe-Mitarai, Y. Ro and H. Harada, svestigation on ~cmsttuctuteand F~~~ of 17 Y. Yamabe-Mtarai, M.-H. Hong, Y. Ro and H. Qmternary If-Based Alloys’, “Key Engineering Harada, l‘hikx. Mq. Lett., 1999,79, (9,673 Materials”, Vols. 171-174,2OOO, pp. 677-684 18 F. R N. Nabarro, Muw. Sci En&, 1994, A184,167
PhftnmMe.+& Reu., ZOOO, 44, (4) 165 19 P. J. W, N. Adams, T. Bigs, P. Ellis, S. Taylor and 28 K. P. Ngwenya and I. M. Wolff, ‘Precipitation I. M. Wolff, ‘Platinum Alloys Based on Pt-PtAl for Strengthening and Age-Hardening in Ferritic Ultra-Hlgh Temperature Use’, presented at the 5th Fe-Cr-Al-Ru Alloys’, Sm Mufez, in press Int Conf. Structural and Functional Intennetallics, 29 M. R. Jackson, U.S. Patent 4,983,356; 1991 Vancouver, Canada, 16th-20th July, 2000 30 R. L. Fleischer, Phihum Mefuh Rev., 1992, 36, (3), 20 P. J. Hill, Y. Yamabe-Mitarai and I. M. Wolff, 138 ‘High-Temperature Compression Strengths of 31 R L. Fleischer, R. D. Field and C. L. Briant, Me&. Precipitation-Strengthened Ternary Pt-Al-X Alloys’, Trans. A, 1991,22A, 403 Sm Muh..,in press 32 I. M. Wolff, JOM, 1997, 34 21 S. D. Dahlgren, Truns. Mefd Sot. AI2ME, 1967,239, 33 I. M. Wolff, L. A. Cornish, G. Sauthoff, H. De V. 1867 Steyn and R. Coetzee, ‘Structure-Property Application Relationships in Ruthenium Aluminide 22 A. J. Bradley, J. Imn andstcellnst..,1951,168, 233 RUAL’, op. df., (Ref. 2), pp. 815-823 23 H. A. Calderon, M. E. Fine and J. R. Weeman, 34 I. M. Wolff and G. Sauthoff, Acta Mutec, 1997,45, Metarz! Truns. A, 1988,194 1135 0,2949 24 R Taillard, A. Pineau and B. J. Thomas, Mater Jd. 35 I. M. Wolff, MetaIL Muter. Trans. A, 1996, 274 3688 Eng, 1982,54,209 The Authors 25 S. M. Zhu, S. C. Tjong and J. K. L. AcfuMatw., Lai, Ira Wolff is Head: Advanced Materials, in the Physical Metallurgy 1998,46, (9), 2969 Division, Mintek. He acts as convener for the Platinum 26 I. M. Wolff, L. E. Iorio, T. Rumpf, P. V. T. Scheers Development Initiative (PDI), which fuels his main interests in and H. Potgieter, Mufm Sd. Eng. A, 1998,241, (1-2), product development based on the platinum group metals. 264 Patricia Hill is Senior Engineer: Advanced Materials, at Mintek. Her interests are primarily in the field of phase and structure-property 27 K P. Ngwenya and I. M. Wolff, ‘Precipitation relationships in the platinum group metal systems. She is currently Strengthening in Ferritic Fe-Cr-Al-Ru Alloys’, Pmc. on secondment to the NRIM, Japan, where she is participating in Ek&n Mimsc. Sot. S. Af;.,1999,29, p. 19 the High Temperature Materials HTM-21 Programme. Core/Shell Bimetallic and Trimetallrc Nanoclusters A core/shell metallic microstructure usdy or microclusters, next coagulation of one type of refers to a metal bound, for example, to a polymer, atom or microcluster to form core clusters, and denber or carbon nanostructure of colloidal lastly deposition of the second metal atoms or dimensions (- 1-1000 nm). Such structures are microclusters onto the core dusters to form shells. usually monometallic and have interesung proper- Structures are controlled by the reduction potential ties, such as combined heterogeneous and of the metal ions and the coordinating ability of homogeneous catalytic properties. However, there the metal atoms or microdusters to the PVP. In are bimetallic core/shell dusters where one metal this way core/shell clusters of Pt/Ru, Au/Pt, is the core, and the second forms a shell around Au/Pd and Au/Rh of diameters - 1.9-2.6 nm the first. Until recently these structures and their were produced. When tested for visible-light- properties had not been examined. induced electron transfer, the bimetallic Pt/Ru Two recent papers from the Science University nanoclusters had the hgher catalytic activity. of Tokyo in Yamaguchi, Japan, (N. Toshima, Pure The second paper describes a radiolytic method A@L Chem., 2000, 72, (1-2), 317-325), and from to produce Pd/Au and Pd/Au/Ag bi- and the University of Notre Dame, U.S.A., (A. trimetallic colloids. Hydrogen reduction of PdC&*- Henglein, J. Pbs. Chem., B, 2000, 104, (29). at room temperature gave Pd nanoparticles. Gold 6683-6685) discuss the preparation of core/shell shells (from K~AU(CN)~),and silver shells (from bi- and trimetal nanodusters. NaAg(CN)$ were then deposited. Colloidal smc- In the first paper colloidal core/shell bimetal tures and absorption spectra were examined. dispersions were prepared from mixtures of two of The Foundation of the Metric System in HAuCL, H2PtC&, PdC12, RhC13 and RuCl3. The France in the 1790s metal ions were reduced simultaneously by alcohol under mild conditions in the presence of the pro- In the July 2000 issue of Pkztinum Metals Review on page 125, the date on which the platinum metre and tective polymer poly(N-vinyl-2-pyrrolidone), PVP. the platinum kilogramme were deposited in the The reaction occurred in stages, first by metal ion French National Archives should be 22nd June coordination, then their reduction to metal atoms 1799, not 22nd July 1799.
PMntm Metair b.,2000,44, (4) 166 A Concise Encyclopedra of Catalysis CATALYSIS FROM A TO Z EDITED BY BOY CORNILS, WOLFGANG A. HERRMANN, ROBERT SCHLOGL AND CHI-HUEY WONG, Wiley-VCH, Weinheim, 2000, 640 pages, ISBN 3-527-29855-X, fl30
Classically, catalysts are defmed as materials that usually well detailed, sometimes illustrated, albeit alter the rate of a chemical reaction without being in some cases generalised. In a few cases the infor- consumed or altered in the process. The chemicals mation is sketchy or oversimplified. As may be industry relies heavily on the use of catalysts to expected in a volume of this nature there are occa- achieve chemical reactions at acceptable rates of sional missed cross references or missing entries, reaction and with desired product selectivity. It is however these are few in number and do not estimated that over 80 per cent of all chemical and detract from the overall excellent quality. oil processing products are obtained with the aid Throughout, there is considerable reference to of catalysts. Catalysis has thus emerged as an the platinum group metals as catalysts in all rele- essential technology spanning many of the disci- vant processes; but whereas electrocatalysis is plines in science and engineering, both in industry barely mentioned, fuel cell catalysis is covered. and academia. As a consequence few, if any, peo- Since the book is intended as a first stop, point ple are familiar with details of all aspects and of reference guide, many entries have references terminologies used in the various areas of catalysis, either to further comprehensive reference works since practitioners in disciplines such as homoge- and textbooks on the subject or to primary scien- neous, heterogeneous, biological catalysis and tific literature and articles. This enables the reader industrial process catalyst engineering fields have to access detailed and specialist information, all developed specialist terminologies relevant to beyond the scope and intentions of the book, very their art. This encyclopedia, “Catalysis from A to quickly and easily. French and German translations Z”, specifically covering catalysis, is thus welcome. of the keyword are given at the end of each entry. The book contains approximately 3000 entries Of particular interest to the reviewer are the which provide concise explanations or descrip- entries of industrial processes which are listed tions of the keywords in question. The keywords under either the name of the company, such as BP, cover most of the terminology likely to be encoun- Shell, UOP, Monsanto, where appropriate, or the tered and used by practitioners on all aspects of process or reaction name, such as BP Cativa catalysis. These include descriptions used in cata- process, SHOP process and Monsanto Gdopa lyst preparation: impregnation for example, and in process. As a result the book provides quick, easy fundamental, theoretical and applied studies of cat- and straightforward reference and insight to the alysts, for instance kinetics, density functional range and extent of technologies, processes and theory, phase transfer catalysis as well as character- products developed worldwide across the chemi- isation methods and techniques used. Concise cals industry by many different companies. descriptions of most of the important industrial This book will be an extremely useful reference processes, reactions and technologies are included, book for scientific libraries and to practitioners in for example Fischer-Tropsch synthesis, LPO (low the field. While reviewing this book, my colleagues pressure 0x0) processes, hydrogenation and oxida- and I spent many pleasant hours testing (and tion. The 164 contributors, mostly European, who increasmg) the extent and breadth of our knowl- have supplied the information are from academia edge of catalysis. I am sure many others will enjoy and industry, and all are active in catalysis. doing the same. P. JOHNSTON Besides the clear concise descriptions for each entry, there is extensive cross referencing through- Peter Johnston is a Consulting Chemist in the Process Catalyst Development Group, Johnson Matthey, Royston. His main interests out. The level of information given in each entry is include the development and manufacture of heterogeneous catalysts.
Phfinwn Me& Rm, 2000,44, (4), 167 167 Metathesis CatalvsedJ bvJ the Platinum Group Metals A NEW STRATEGY FOR THE SYNTHESIS OF ORGANIC COMPOUNDS AND POLYMERS PART 111: ACYCLIC DIENE METATHESIS REACTIONS AND RING-OPENING METATHESIS POLYMERISATIONS
By V. Dragutan and I. Dragutan Institute of Organic Chemistry, Bucharest. Romania and A. T. Balaban Polytechnic University of Bucharest, Romania
Thefirst two parts of this paper appeared in the April and July issues of this Journal. Part I looked at types ofplatinum group metals catalysts and metathesis activity and selectivity. Part II examined specific syntheses catalysed by these catalysts, in particular; reactions catalysed by ruthenium carbenes. This resulted in the syntheses of various carbocycles, heterocycles, metallacycles, crown ethers, polycyclic polymers, natural compounds and sub-units of biologically active compounds. The concluding part of this review deals first with acyclic diene metathesis and then with ring-opening metathesis polymerisations, and ranges of products formed by these reactions are given.
Following on from Part II of this review in the ADMET reaction of vinylsilanes turned out to which platinum group metals catalysts takmg part be particularly effective, see Equation (xl) below, in tifig-dosed metathesis reactions were consid- (63). ered, Part III looks at this group of catalysts as they are used for acyclic diene metathesis reactions and Ring-Opening Metathesis for ring-opening metathesis polymerisations. Polymerisation Ring-opening metathesis polymerisations Acyclic Diene Metathesis Reactions (ROMPS)have great industrial sqpflcance. The The acyclic diene metathesis (ADMET) reac- use of metathesis platinum group metals catalysts tion of divinylsilanes and divinylsiloxanes was in polymer synthesis by ROMP has become a performed in the presence of homogeneous ruthe- ubiquitous catalytic process in polymer chemistry. nium- and rhodium-containing systems in combination with cocatalysts of the HSi-type, see ROMP of Functionalised Cycloolefins Equation (Xxxix), (62). Since their early application in ROMP of nor- The application of ruthenium hydride complex- bornene and its derivatives (lo), salts and es, in particular RuHCl(CO)(PPh3)3, as catalysts in complexes of ruthenium, iridium and osmium,
I RR
PhtinwnMdxalr Rev., 2000,44, (4), 16S172 168 because of their tolerance toward functional lysts. For instance, 5-(aimethylsiloxy)norbom-2- groups, have been widely employed in metathesis ene, 5-(uiethylsiloxy)norbom-2-ene and 5-(tr- polymerisation of a variety of functionalised methylsiloxy)methylnorborn-2-ene readily give cycloolehns. Solvents used have been various mix- silicon-containing polymers in the presence of tures of water, ethanol and halogenated organic RUC~~(PP~~)~catalyst with chlorobenzene/ethanol solvents (1 (a), 1(b)). as solvent, see Equation (xliii), where X = Si(OR), A first example of ROMP is the living ring- opening polymerisation of 3-substituted cyclobutenesbearing a wide range of various func- RuCIZ(PPh$3 PhCl IEtOH.60.C tional groups, under the influence of catalysts such -T(xliii) as RuClZ(=CHPh)(PCy3)2,la, or RuCh(=CHCH= CP~;)(PCY~)~,(Cy = cyclohexyl), leading to func- tionalised polybutenamer, see Equation (xli), (64), or CHzOSMe3. Functionalised oligomers and polymers prepared according to this procedure are useful as components of gas separation mem- branes, materials with valuable electrophysical properties, adhesives, precursors of ceramics and I I thermosetting products. where X = OCHZPh, OCPh3,OC(O)Ph, OH, N(i- A new class of glycopolymers was prepared, in P+, OCH2COOMe, (CH&COOH, (CH&OH, a controlled manner, by the living ring-opening (CHz)3CONHBu or (CH2)3COOMe. Depending polymerisation of sugar-substituted norbomenes on the nature of the substituent,the polymer yields using RUC~~(=CHCH=CP~~)(PR~)~(R = phenyl or varied between 87 and 97 per cent. Thus, a new Cy) as the catalyst, see Equation (xliv), where R', class of functionalised polybutadi- enes that are difficult to prepare by conventional methods have been synthesised by this route. Among the ruthenium carbene complexes, of general formula RuCl2(=CHCH=CPh2)(PR3)Zrthe one bearing tris(cyclohexy1)phos- phine Wds(R = Cy), has proved to be the most active and able to polymerise less strained olefins such as R"= H, COCH,, CHZPh, SiEt:, or R' = H and R" cyclooctene and derivatives, see Equation (xlii), = CPh3, (66). This type of glycopolymer finds interesting applications in the modulation of cell adhesion, immobilisation of particular cell types and the study of multivalency in extracellular inter- "OX&& (xlii) actions. With the recent development of a new genera- (65), where X = OH, Ac, Br or OCOCH,. A fam- tion of carbene metal complexes that are more ily of ternary copolymers of butadiene, ethylene tolerant to proiic solvents and water, living ROMP and vinyl derivatives was manufactured by this of cyclic olehns can now be carried out in these method. media under rigorously-controlledconditions (67). Of great interest is the synthesis of poly- Latex particles based on polynorbomene and norbomene substituted with silicon-containing polybutadiene were thus obtained by ROMP of groups, using ruthenium complexes as the cata- norbomene and 1,5-cyclooctadiene in a mixture of
PIatnum Metah Rm, 2000,44, (4) 169 reported by Novak and Grubbs (9) using RuCl,, pucl3(1,5- COD)] and oscl3 (1,5-COD = 1,5-cyclooctadiene), see Equation (xlvi), where R = H; R’ = H, CH20H,CHz0CH3 or CHzOTMS; R” = CH3, CH20H, CHzOCH3 or CH20TMS. The poly(7-oxanorbornenes) result- PEO ing from the selective metathesis polymerisation of the 7-oxanorbornene monomers (xlvi) are of keen interest for their R R‘ R“ potential ionophoric properties. In addition to binding ions in dichloromethane/ethanol, using a-norbomenyl- solution, these polymers act as ion permeable PEO ((poly(ethy1ene oxide), a water-soluble resin) membranes. macromonomer as a stabiliser and the ruthenium This reaction has been successfully applied to a benzylidene complex, RuClz(=CHPh)(PCy3)2, la, large number of heterocyclic monomers using var- as initiator, see Equation (xlv). ious ruthenium complexes (21, GS70). As a result This was the &st time that such a polymerisable of these developments, the direct synthesis of surfactant was used to obtain latex particles by dis- ABA triblock copolymers of different 7-0XanOr- persion ROMP of cyclolefins. These PEO-based bomene derivatives has been efficiently performed macromonomers function both as co-monomers by living ROMP using the well-defined, bimetallic of cycloolefins in the ROMP process and as ruthenium catalyst, of general formula, stabilisers of the formed polyalkenamer. The RUC~~(PR~)~(=CHC~H,CH=)RUC~Z(PR~)~,5. presence of the norbomenyl group at one end of Starting for instance from N-methyl-7-oxanor- the chain helps these novel surfmers (surfactant bomene-2,3-dicarboxylic hide and the bimetallic monomers) to anchor chemically onto solid sup- ruthenium catalyst, 5, a homopolymer is first porting particles, while their hydrophilic part obtained. Then by adding N-octy-7-oxanor- serves as a steric barrier. bomene-2,3-dicarboxylic hide the ABA triblock copolymer is readily formed, see Equation (xlvii) ROMP of Heterocyclic Olefins below, (26). Such copolymers have low polydisper- Because of their tolerance toward heteroatoms, sities and a controlled molecular weight. it became possible for numerous catalysts contain- ing platinum group metals to be employed in the ROMP in Water ring-opening polymerisation of heterocyclic Nowadays, there is extensive documentation monomers. The first successful ROMP of a series for the ROMP of strained, cyclic olefins in aque- of monomers based on 7-oxanorbomene was ous media, initiated by platinum group metals salts
Phtinum Mctalr Rev., 2000, 44, (4) 170 and coordination complexes, particu- larly by those of ruthenium (23(a), 71-73). We mention here the living ROMP of hydrophobic monomers derived from 5,b-disubstituted nor- bornenes under the action of RuCl*(=CHPh)(PCy&, la, in the presence of water, see Equation (xlviii), (74), where R = OMe or OSi('Bu)(Me)z. The reaction in the presence of an emulsifier yielded latexes of nearly monodisperse prod- ucts which are ideal for the preparation of tacky polymers. Although these of norbornene-2,3-dicarboxyIic imide have been complexes served as robust metathesis polymeri- prepared quantitatively with soluble ruthenium sation catalysts in water, polymerisations were not alkylidenes 3 and 4, see Equation (l). always living and inefficient hitiation steps pro- It is noteworthy that polymerisations are not duced erratic results (typically less than 1 per cent "living" in the absence of acid. The role of the acid of the metal centres were converted to catalytical- in these systems appeared to be two-fold: fist to ly active species). eliminate the traces of hydroxide ions which could However, true living ring-opening polymerisa- cause catalyst decomposition and second to tion of hctionalised cycloolefins in water has enhance the catalyst activity and stability by proto- been achieved with ruthenium complexes 3 and 4 nation of one of the phosphhe ltgands. (see Part I) (75) in the presence of a Brcansted acid. In fact, the most efficient ROMP catalyst Thus, an N-substituted norbornene-2,3-dicar- described so far (combining activity comparable to boxylic imide has been quickly and quantitatively the molybdenum-based catalysts and stability like polymerised with catalysts 3 or 4 and DC1 (1 other ruthenium-based catalysts) appears to be la, equivalent relative to alkylidene) in the absence of but with one of the phosphine hgands being surfactant or organic solvents, see Equation Q, replaced by an electron-donating imidazoline (25). carbene hgand having two N-mesityl groups (76). Water soluble polymers and block copolymers with low polydispersities and controlled molecular Concluding Remarks weight have been prepared by this technique (25). Metathesis catalysts based on platinum group For instance, block copolymers of N-substituted metals exhibit numerous advantages over their ammonium salts of 7-oxanorbornene-2,3-dar- classical heterogeneous and homogeneous cour- boxylic imide and N-substituted ammonium salts terparts. Essentially these catalysts:
Plniinwm McfdRev., 2000,44, (4) 171 (a) extend the metathesis reaction in polar and 72 M. B. France, R H. Grubbs, D. V. McGrath and R Paciello, Mammokmks, protic solvents including alcohols and even water 1993,26,4742 73 T. Viswanathan, J. Jethmalani and A. Toland, /. or much more acidic environments (for example, AppL Polym. Sci, 1993,47,1477 phenols or strong acids such as trichloroacetic 74 D. M. Lynn, S. Kanaoka and R H. Grubbs, /. Am. acid) Cbem. Soc., 1996,118,784 75 V. Dragutan, I. Dragutan and A. T. Balaban, (b) tolerate well many heteroatom-containing (for Phtinm Metalr Rey., 2000,44, (2), 58; ibid, 2000,44, example, 0, N, P, Cl, Br) functional groups, hence (3). 112 a wide profile of substrates 76 C. W Bielawski and R. H. Grubbs, Anp. Cbem. Int. Ed, 2000,39,2903 (c) allow worldfig under normal temperature and pressure, in common solvents, without special The Authors Professor A. T. Balaban, of the Romanian Academy, taught purification and chemistry at Bucharest Polytechnic University for over 40 years. (d) can be conveniently stored in air without sub- He now teaches at Texas A & M University, Galveston, TX. His interests include homogeneous catalysis, heterocyclic compounds stantial decomposition - even for weeks. (pyrylium, pyridinium, oxazole), stable free radicals, and theoretical Recently a new generation of catalysts, derived chemistry including chemical applications of graph theory and topological indices used in quantitative structure-activity mainly from Grubbs' ruthenium carbenes, has been relationships, one index being known as Balaban's index J. designed and applied successfully in the metathesis kana Dragutan is a Senior Researcher at the Institute of Organic of functionalised olefins and cycloolefins, in ring- Chemistry of the Romanian Academy. Her research interests include sterically hindered amines; synthesis of olefinic monomers closing and riugopening metathesis and in living via olefin metathesis; stable organic free radicals as spin probes for metathesis polymerisation of functionalised ESR of organised systems and membrane bioenergetics; and cycloolefins and heterocycloolefins. Particular transition metal complexes with free radical ligands. attention is presently being devoted to creaang Valerian Dragutan is a Senior Researcher at the Institute of Organic Chemistry of the Romanian Academy. His current research attracdve methods for the synthesis of new hetero- interests are homogeneous catalysis by transition metals and cycles, natural compounds with biological activity Lewis acids: olefin metathesis and ROMP of cycloolefins; bioactive organometallic compounds; mechanisms and stereochemistry of and sub-units of biologically-interesting organic reactions in organic and polymer chemistry. comDounds ha* comDlex architecture. Silphenylenesiloxane Polymers References Polysiloxanes are polymers with an alternating 62 (a) S. Cummings, D. W Smith, K. B. Wagener, R of silicon and oxygen atoms. Polysiloxanes h4iller and E. Ginsburg, Po&~er Pqb. (ACS, Diu. chain PoZymer Cbm.), 1995,36,697;@) D. W. Smith and K. have a range of very valuable properties which are B. Wegener, Mmmokmks, 1993,26,1633;(c) D. W. utilised commercially: inertness, resistances to water Smith and K. B. Wegener, ibid, 1993,26,13533 and oxidation, and hgh thermal stabilities. However, 63 E. Sh. Finkel'stein,PolymerSci, Sn: B, 1995,37,185 little work has been done to develop dehydrocou- 64 B. R Maughon and R H. Grubbs, Mmmokcnks, pling polymerisation to give polysiloxanes. A team 1997,30,3459 of scientists at the University of Cincinnati have 65 M. Hillmyer, W. R Laredo and R. H. Grubbs, now developed a general method of dehydtocoupling Mmmokmks, 1995,28,6311 polymerisation to give alternating copolymers of 66 C. Fraser and R H. Grubbs, Mmmokmks, 1995,28, silphenylenedoxanes from bis-shes and disilanols, 7248 under mild conditions, using Wilkinson's catalyst, 67 V. Heroguez, M. Fontanille and Y. Gnanou, 13th Int. Symp. on Olefin Metathesis and Related RhC1(Ph3P)3, (R zhang, J. E. Mark and A. R Processes, Rolduc, Kerkrade, The Netherlands, July Pinhas, Mmmo.'em.'es,2000,33, (lo), 3508-3510). 11-15,1999,Abstracts, p. 23 Silphenylenesilane polymers with controllable 68 R H. Grubbs, Polymer Pnp. (ACS, Div. Polymer microstructures and average molecular weight of Cbm.), 1992,33,163 10,100 g mol-' were produced. The best polymeii- 69 M. A. Hillmyer, C. Lepetit, D. V. McGrath, B. M. sation occurred betweenpbis(dimethylsily1)benzene Novak and R H. Grubbs, Mamnmkcnk.r, 1992,25,3345 and p-bis(dimethylhydroxysily1)benzene. Among 70 (a) K H. MOMM. Gingras and L. L. Kiess-1. other alternating copolymers produced were poly- Am. Cbm. Soc., @) K. H. Mortell, 1994,116,12053; (tea;M.thy--p~ph~ylenesiloxane)@oly-"S) and R. V. Weatherman and L. L. Kiessling,]. Am. Cbem. Soc., 1996,118,2297 a combination of tetramethyl-m-silphenylenesilox- 71 B. M. Novak, W. Risse and R H. Grubbs, Adu. ane and TMPS. The rhodium catalyst was very P~lym~Sci.,1992,102,47 efficient and robust under the reaction conditions.
P.4tinm Metah Rcv., 2000,44, (4) 172 The Discoverers of the Platinum Isotopes THE DISCOVERY OF THE THIRTY SEVEN KNOWN PLATINUM ISOTOPES BETWEEN 1935 AND 1996
By J. W. Arblaster Rotech Laboratories, Wednesbury, West Midlands WSlO 786,U.K.
The history of the discovery of the isotopes of platinum, made over some 61 years between 1935 and 1996, can be gleanedfrorn the various editions of the monograph “Table of Isotopes” (Id).However; except for a few cases, in general, little attempt has been made to correlate the circumstances of the discoveries of the isotopes of individual elements. In this article attention is drawn to the work of pioneering scientists who in a comparatively short period of creativity discovered the majorip of the isotopes of platinum.
There are thtrty-seven known isotopes of plat- 1949 using the mass spectrographic technique and inum and six of these occur naturally with the was shown to be radioactive by Porschtn and authorised isotopic abundances stated below (9). Riezler in 1954 (16)).The half-life of ‘vt is cur- rently accepted as 6.5 x 10” years (650 Gy) (17). I The Naturally Occurring Isotopes of Platinum I Artificial Platinum Isotopes Isotopic Mass number In 1935, the possible existence of radioactive abundance, % I platinum isotopes was inferred by McLennan, lWpt 0.014 Grimmett and Read (18) at the Radium Institute, 192pt 0.782 London, and also by Amaldi and colleagues in 194pt (19) 32.965 the Physics Laboratory at the University of Rome 195pt 33.832 196pf 25.142 by slow neutron bombardment of the metal. 198pt 7.1 63 However, the mass numbers could only be guessed at until later in the same year when Dempster iden- Of these, the five major isotopes were discov- tified the major naturally occurring isotopes using ered by Dempster at the University of Chicago, his new type of mass spectrograph. Illinois, in 1935 using a new type of mass spectro- The first definite identification of a radioactive graph; however, he only identified the mass platinum isotope was probably in 1936 by Cork numbers (10). The actual isotopic abundances and Lawrence (20) in the Department of Physics were measured using the same technique by of the University of California who produced an Sampson and Bleakney in 1936 (ll),although ear- isotope with a half-life of 14.5 hours. They used lier in the same year Jaeckel and Kopfermam (12) chemical means to identify the isotope as platinum and Kopfermann and JSrebs (13) had obtained rea- and assigned it to the ‘missing‘ I9’Pt. sonable estimates of the relative isotopic ratios of A year later, McMiUan, Kamen and Ruben (21) the four major isotopes (the last four) by a study of at the same Department of Physics produced an the hyperfine structure of the neutral platinum isotope which had a half-life of 18 hours. This was spectra. An earlier attempt by Venkatesachar and also chemically identified as platinum and assigned Sibaiya to use this technique for platinum led to a to 19’Pt. Although both set of claims were initially misidentification of the mass numbers of the tentative, the two teams of claimants have subse- major isotopes (14). quently been credited with the discovery of this The rare isotope, I9’Pt, was identified by isotope in the “Table of Isotopes” (1-8). Duckworth, Black and Woodcock (15) at the The major period of discovery was, however, in Wesleyan University, Middletown, Connecticut, in the 1960s when sixteen new isotopes were
P&nnm Metah h.,2000,44, (4), 173-178 173 I The Discoverers of the Platinum Isotopes
Mass number Half-life Decay modes Year of Discoverers Ref. Notes discovery - 166 300 ps a 1996 Bingham etal. 25 167 700 ps a 1996 Bingham eta/. 25 168 2.0 rns a, EC t p’ ? 1981 Hofmann eta/. 26 A 169 3.7 ms a, EC t p’ ? 1981 Hofmann eta/. 26 170 14.7 ms a,EC t p’ 1981 Hofmann eta/. 26 171 38 ms a, EC t p’ 1981 Hofmann ef a/. 26 B 172 98 ms a, EC t p’ 1975 Cabot eta/. 27 C 173 363 ms a, EC t p’ 1966 Siivola 22 D 174 898 ms a, EC t p’ 1966 Siivola 22 175 2.52 s a, EC t p’ 1966 Siivola 22 176 6.33 s EC t p’, a 1966 Siivola 22 177 10.0 s EC t p’, a 1966 Siivola 22 178 21.1 s EC t p’, a 1966 Siivola 22 179 21.2 s EC t p’, a 1966 S iivo la 22 180 52 s EC t p,a 1966 Siivola 22 181 51 s EC t p’, a 1966 Siivola 22 182 2.2 min EC t p’, a 1963 Graeffe 23 183 6.5 min EC t p’, a 1963 Graeffe 23 183m 43 s EC t p’, IT ? 1978 Visvanathan eta/. 28 184 17.3 rnin EC t p, a 1963 Graeffe 23 E 184rn 1.01 ms IT 1966 Burde, Diamond and Stephens 29 185 70.9 min EC t p’, a 1960 Albouy, Gusakow and Poffe 30 185111 33.0 min EC t p’, IT ? 1970 Finger eta/. 31 186 2.08 h EC t p’, a 1960 Albouy, Gusakow and Poffe 30 F 187 2.35 h EC t p’ 1960 1: Albouy, Gusakow and Poffe 30 2: Baranov eta/. 32 3: Malysheva eta/. 33 188 10.2 d EC, a 1954 Naumann 34 189 10.87 d EC t p’ 1955 Smith and Hollander 35 190 650 Gy a 1949 Duckworth, Black 15 G and Woodcock 191 2.80 d EC 1947 Wilkinson 36 192 Stable - 1935 Dempster 10 193 50 Y EC 1956 Naumann 37 H 19311-1 4.33 d IT 1947 Wilkinson 36 194 Stable - 1935 Dempster 10 195 Stable - 1935 Dempster 10 195m 4.02 d IT 1951 Huber etal. 38 I 196 Stable - 1935 Dernpster 10 197 19.892 h P- 1936 Cork and Lawrence 20 J 197117 95.4 min IT, P- 1952 Christian, Mitchell and Martin 39 K 198 Stable - 1935 Dempster 10 199 30.8 rnin P- 1937 McMillan, Kamen and Ruben 21 L 199m 13.6 s IT 1959 Walgren and Meinke 40 200 12.5 h P- 1956 Roy, Roy and Merritt 41 201 2.5 rnin P- 1962 Facetti eta/. 42 202 44 h - 1992 Shi etal. 43
s is second, min is minute. h is houc d is duy, y is year ms is millisecond (/O-‘s), p is microsecond (lon s). Gx is gigayeor (IO‘yJ
Phtinwn Mckrls h.,2000,44, (4) 174 Arthur Jeffrey Dempster 18861950 The US.physicist Arthur Dempster joined the faculty of the Depurtment of Physics at the University of Chicago, Illinois, in 1919. He developed the double focusing mass spectrograph in 1935 and used it to muke thejrst isotopic analyses of platinum. iridium, palladium and gold. Between 1920 and 1939 he is credited with the discovery or co-discovery of forty-jive nuturally occurring isotopes of nineteen elements. At his death A. J. Dempster was Professor of Physics at the University of Chicago Uniwrsin. of Chicago. r.nurie.ry <$Alp Emilio Se& Vi.rud Archives announced. In 1966, the Finnish physicist, Anm isotopes have half-lives in the millisecond region Siivola, working at the Lawrence Radiation they are all alpha emitters, so that for platinum the Laboratory, University of California, announced proton drip line (see Appendix) has not yet been the production and identification of nine new iso- crossed. The latest research to take place will be topes of platinum (22). He also contirmed three looking for the isotope 165Pt,which is likely to others which had been discovered by Graeffe in decay by alpha emission. This work is connected 1963 at the University of Helsinki (23). with experiments which are searching for the pro- More recently work has been concentrated on ton emitting isotope '%. discovering the hght isotopes and although such The actual methods for the production and
Anm' Siivola From 1963 to 1965 the Finnish physicist worked at the Lawrence Radiation Laboratory. Berkeley, University of Culifornir~. later returning to the University of Helsinki. Between 1966 and 196R hr announced the production and identification of nine new isotopes of platinum. seven of iridium, seven of gold, jve of lead arid six of bismuth (six ground state isotopes arid three isomrric states). Anni Siivola became Professor of Physics, Head of the Department of Physics and Dean of the Faculty of Science at the University of Helsinki. He retired from the University of Helsinki in October 1999 (lxhiikuw Ov) Rur Fcurarc~
PLdnnm Me& b.,2000,44, (4) 175 Notes to the Table A 16'Pt Alpha energy only, the half-life was measured by Bingham eta/. in 1996 (25). B 171Pt Alpha energy only, the half-life was measured by Della Negra eta/. in 1981 (44) and Enge eta/. in 1981 (45). c '72Pt Alpha energy only, the half-life was measured by Enge eta/. in 1980 (45,46). D i73Pt Alpha energy only, the half-life was measured by Cabot eta/. in 1975 (27). E lUPt The half-life, determined by Graeffe at 20 minutes, was confirmed by Siivola in 1966 (22). Other reported values are 2.6 hours by Malysheva eta/. in 1960 (33) and 42 minutes by Qaim in 1964 (47). F lWPt Smith and Hollander first characterised this isotope in 1955 but incorrectly assigned the mass number as 187 (35). This mistake was indirectly corrected by Scharff-Goldhaber eta/. in 1957 (48) who reassigned the mass number of a daughter isotope from lS7lrto la61r. G lgoR The radioactive nature of this naturally occurring isotope was discovered by Porschbn and Riezler in 1954 (16). H Ig3Pt Naumann only determined the half-life to be less than 500 years. The accepted value was determined by Soy, Ravn and Bsgeholt in 1971 (49). I i95mPt Non-specified activities of 3.3 days by McMillan, Kamen and Ruben in 1937 (21) and 3.45 days by Hole in 1948 (50) were assigned to Ig5"'Ptby the "Table of Isotopes". J "'Pt Although the claimed discovery by Cork and Lawrence was tentative (20), a later assignment by McMillan Kamen and Ruben in 1937 was equally tentative (21). K i97mPt Non-specified activities of 80 minutes by Sherr, Brainbridge and Anderson in 1941 (51), 78 minutes by Hole in 1948 (50) and 87 minutes by Mock eta/. in 1948 (52) were assigned to lg7"'Rby the 'Table of Isotopes".
L '99Pt Non-specified activities of 36 minutes by McLennan, Grimmett and Read (18) and 50 minutes by Amaldi eta/. (19), both in 1935, were assigned to IggPtby the "Table of Isotopes".
Decay Modes a Alpha decay is the emittance of alpha particles which are 4He nuclei. Thus the atomic number of the daughter nuclide is lower by two and the mass number is lower by four. fl- Beta or electron decay for neutron-rich nuclides is the emittance of an electron (and an anti-neutrino) as a neutron decays to a proton. The mass number of the daughter nucleus remains the same but the atomic number increases by one. p' Beta or positron decay for neutron-deficient nuclides is the emittance of a positron (and a neutrino) as a proton decays to a neutron. The mass number of the daughter nucleus remains the same but the atomic number decreases by one. However, this decay mode cannot occur unless the decay energy exceeds 1.022 MeV (twice the electron mass in energy units). Positron decay is always associated with orbital electron capture (EC). EC Orbital electron capture. The nucleus captures an extranuclear (orbital) electron which reacts with a proton to form a neutron and a neutrino, so that, as with positron decay, the mass number of the daughter nucleus remains the same but the atomic number decreases by one. IT Isomeric transition, in which a high energy state of a nuclide (isomeric state or isomer) usually decays by cascade emission of y (gamma) rays (the highest energy form of electromagnetic radiation) to lower energy levels until the ground state is reached. However, certain low level states may also decay independently to other nuclides. P The emittance of protons by highly neutron-deficient nuclides. As the neutron:proton ratio decreases a point is reached where there is insufficient binding energy for the last proton which is therefore unbound and is emitted. The point at which this occurs is known as the proton drip line and such nuclides are said to be "particle unstable". n The emittance of neutrons from highly neutron-rich nuclides. As the proton:neutron ratio decreases a point is reached where there is insufficient binding energy for the last neutron which is therefore unbound and is emitted. The point at which this occurs is known as the neutron drip line. The heaviest platinum isotopes still have half-lives in the minutes to hour region and it is therefore likely that many more neutron-richisotopes remain to be discovered before the neutron drip line is reached.
Phrtinm Mcfah h.,2000,44, (4) 176 Appendix Some of the Terms Used for this Review Atomic number the number of protons in the nucleus Mass number the combined number of protons and neutrons in the nucleus Nuclide and isotope A nuclide is an entity characterised by the number of protons and neutrons in the nucleus. For nuclides of the same element the number of protons remains the same but the number of neutrons may vary. Such nuclides are known collectively as the isotopes of the element. Although the term isotope implies plurality it is sometimes used loosely in place of nuclide. Half-life the time taken for the activity of a radioactive nuclide to fall to half of its previous value Electron volt (eV) the energy acquired by any charged particle carrying a unit (electronic) charge when it falls through a potential of one volt. It is equivalent to 1.602 x J. The more useful unit is the mega (million) electron volt, MeV.
identification of the isotopes are given in the orig- a manuscript date or a conference report date. If inal reports and summarised in the Table of The the discovery was announced by different groups Discoverers of the Platinum Isotopes. at the same time, but independently, then all are In this Table the mass number of each isotope included in an order which makes use of the above is listed together with the half-life as selected by dating system. the compilers of the NUBASE Data Base (17). However, the data for ””Pt comes from a more Criteria for Discovery recent review (24). Isomeric states (indicated by Most impoftant are the criteria for the correct the suffix “m”) are included if their half-lives identifications of the atomic number and the nxgis exceed one millisecond or if they are a significant number of isotopes, although the sequence of dis- fraction of the half-life of the ground state, if the covery is not considered to be complete until an latter is also short. The principal decay modes are important radiation property, such as the half-life, listed in order of abundance, with a question mark or in the case of alpha emitters, for example, the indicating that the decay type is either expected or unique alpha energy spectrum, has been measured. has been detected but that the percentage abun- In the ‘Notes to the Table’ if the alpha energy dance has not been measured. spectrum was found first, the &st determination The year of discovery of an isotope is generally of the half-life is also included. For naturally- taken to be the year in which the discovery was occurring isotopes, discovery is considered to be placed in the public domain and is therefore either the first identification by mass spectrography.
References
1 J. J. Livingwood and G. T. Seaborg, Rw. Mod Pbs., 7 E. Browne, J. M. Dairiki, R E. Doebler, A. A. 1940,12,30 Sbihab-Eldin, L. J. Jardine, J. K Tuli and A. B. 2 G. T. Seaborg, Rev. Mod PLys., 1944,16,1 Buym, “Table of Isotopes”, 7th Edn., C. M.Lederer and V. S. Shirley (eds.), Wiley Interscience, John 3 G.T. Seaborg and I. Perlman, Rw. Mod Pbs., 1948, Wiley and Sons Inc., New York, 1978 20,585 8 C. M. Bagh, S. Y. F. Chu and J. Zipkin, ‘Table of 4 J. M. Hollander, I. Perlman and G. T. Seaborg, Rct. Isotopes”, 8th Edn., R B. Firestone and V. S. Mod Ply..,1953,25,469 Shirley (eds.), Wiley Interscience, John Wiley and 5 D. Strominger, J. M. Hollander and G. T. Seaborg, Sons Inc., New York, 1996 Rw. Mod Phys., 1958,30,585 9 Commission on Atomic Weights and Isotopic 6 C. M. Ledera, J. M. Hollander and I. Perlman, Abmdances- Subcommittee for Isotopic Abundance “Table of Isotopes”, 6th Edn., John Wiley and Sons Measurements, Pm&L Cbcm., 1998,70,217 Inc., New York, 1967 10 A. J. Dempster, N&m, 1935,135,993
PMnmMctaL Rm, ZOOO, 44, (4) 177 11 M. B. Sampson and W. Bleakney, Pbys. Rev., 1936, G. Astner, E. Beck, A. Kjelberg, F. Miinnich and P. 50,732 Patzelt, Proc. Int. Conf. on the Properties of Nuclei 12 B. Jaeckel and H. Kopfermann, Z. Pbys., 1936, 99, Far From the Region of Beta-Stability, Leysin, 492 Switzerland, 31st Aug.4th Sept., 1970, Rep. 70-30, Vol. 2,1970, CERN, Geneva, p. 1045 13 H. Kopfermann and K. Krebs, Z. Pbys., 1936, 101, 193 32 V. I. Baranov, K. Ya. Gromov, B. S. Dzhelepov, 14 B. Venkatesachar and L. Sibaiya, Nutun: 1935, 136, Zyong Chong Bai, T. V. Malysheva, V. A. Morozov, Akd 65 and Pmc. Indian Acad SCi, 1935,2,101 B. A. Khotin and V. G. Chumin, IT. Nmk SSSRSer. Fic, 1960,24,1079 (Bur%Ad. Jci USSR 15 H. E. Duckworth, R F. Black and R. F. Woodcock, Pbys. Ser., 1960,24,1086) Pbys. Rev., 1949,75,1438 33 T. V. Malysheva, B. A. Khotin, A. K. Lavtukhina, L. 16 W. Porschh and W. Riezler, Z. Natwtforsch., 1954, N. -ova and V. V. Murav’eva, I?. AdNauk 9a, 701 and ibid., 1956, lla, 143 SSSR Sw. Fit, 1960,24,1109 (Bur%Acd. Sci USSR 17 G. Audi, U. Bersillon, J. Blachot and A. H. Wapsaa, Pbs. Ser., 1960,24,1113) NucL Pbys., 1997, A624,l 34 R A. Naumann, Pbys. Rev., 1954,96,90 18 J. L. McLennan, L. G. Grimmett and J. Read, 35 W. G. Smith and J. M. Hollander, Pbys. 1955, Nature, 1935,135,147 I&., 98,1258 19 E. Amaldi, 0. D’Agostino, E. Fermi, B. 36 G. WiUdnson, Pbys. Rev., 1948, 73, 252 and ibid., Pontecorvo, R Rasem and E. Segrk, Pmc. R SOL. Lnd, 1935,1494 522 1949,75,1019 20 J. M. Cork and E. 0. Lawrence, Pbys. Rev., 1936,49, 37 R. A. Naumann, Bull. Am. Pbys. Soc., Sw. II, 1956,1, 788 42 21 E. McMillan, N. Kamen and S. Ruben, Pbys. Rev., 38 (a) 0. Huber, F. Humbel, H. Schneider and A. de 1937,52,375 Shalit, Hdv. Pbys. Ada, 1951, 24, 629; (b) A. de Shalit, 0. Huber and H. Schneider, ibid., 1952, 25, 22 A. Siivola, Nucl. Pbys., 1966, 84, 385 279 23 G. Graeffe, Ann. Acad Sci Fenn. Jer. A 1963, VI, 39 D. Christian, R F. Mitchell and D. S. Martin, Pbs. (128), 1 Rev., 1952,86,946 24 C. M. Baglin, NucL Data Sheets, 1999, 86,449 40 M. A. Walgren and W. W. Meinke, Pbys. Rev., 1959, 25 C. R. Bingham, K. S. Toth, J. C. Batchelder, D. J. 115, 191 Blumenthal, L. T. Brown, B. C. Busse, L. F. 41 L. P. Roy, J. C. Roy and J. S. Memtt, Pbys. Rev., 1957, Conticchio, C. N. Davids, T. Davinson, D. J. 105,1337 Henderson, R. J. Irvine, D. Seweryniak. W. B. Walters, P. J. Woods and B. E. Zimmerman, Pbys. 42 J. Facetti, E. Trabal, R. McClin and S. Torres, Pbys. Rev., 1996, C54, R20 Rev., 1962,127,1690 26 (a) S. Hofmann, G. Miinzenberg, F. Hessberger, W. 43 S. Shi,W.D. Huang,Y.Li,D. Z.Yin,J. H. Guand Reisdorf, P. Armbruster and B. Thuma, Z. Pbys., J. Q. Tian, Z. Phys., 1992, M42,369 1981, A299,281; (b) S. Hofmann, G. Miinzenberg, 44 S. Della Negra, C. Deprun, D. Jacqet and Y. W. Faust, F. Hessberger, W. Reisdorf, J. R. H. LeBeyec, Z. Pbys., 1981, MOO, 251 Schneider, P. Armbruster, K. Giittner and B. 45 H. A. Enge, M. Salomaa, A. Sperduto, J. Ball, W. Thuma, Proc. 4th Int. Conf. on Nuclei Far From Schier, A. Graue and A. Graue, Pbs. Rev., 1982, Stability, L. 0. Skolen, Helsinger, Denmark, (25,1830 7th-13th June 1981, CERN, Geneva, Rep. 8149, 46 H. A. Dirienzo, J. Molitoris, A. Sperduto, M. 1981, Vol. I, p. 190 Enge, Salomaa, J. Chervanek, J. Ball, W. Schier and H. 27 C. Cabot, C. Deprun, H. Gauvin, B. Lagarde, Y. Wegner, Bu/L Am. Pbys. Soc., 1980,25,486 LeBeyec and M. Lefort, Unpublished work quoted by H. Gauvin, Y. LeBeyec, J. Livet and J. L. Reyss, 47 S. M. Qaim, J. Inorg. NucL Chem., 1965,27,759 Ann. Pbys. (€‘ah)),1975,9,241 48 G. Scharff-Goldhaber, D. E. Alburger, G. Harbottle 28 A. Visvanathan, E. F. Zganjar, J. L. Wood, R. W. and M. McKeown, Private Communication, Fink, L. L. Reidmger and F. E. Turner, Pbys. Rev., November 1957, to R M. Diamond and J. M. 1979, C19,282 Hollander, NucL Pbys., 1958, 8, 143 29 J. Burde, R. M. Diamond and F. S. Stephens, NULL 49 T. Soy, H. L. Ram and P. Bageholt, Pbys. Rev., 1971, P&., 1966, 85, 481 C4,600 30 G. Albouy, M. Gusakow and N. Poffe, J. Pbys. 50 N. Hole, Arkiv. Mat. Asbun. fisik, 1948,364 (9), 1 Wum,1960,21,751 51 R Sherr, K. T. Brainbridge and H. H. Anderson, 31 (a) M. Finger, R. Foucher, J. P. Husson, J. Pby. Rev., 1941,60,473 Jasazebski, A. Johnson, C. Skbille, R. Henck, J. M. 52 D. L. Mock, R C. Waddell, L. W. Fagg and R. A. Kuchly, R. Regal, P. Siffert, G. Asmer, R. R Erdal, Tobin, Pbys. Rev., 1948,74,1536 E. Hagebe, A. Kjelberg, F. Miinnich, P. Patzelt, E. Beck and H. Kugler, Rep. 7Cb29, CERN, Geneva, The Author 1970; (b) The ISOLDE Collaboration, R. R. Erdal, John W. Arblaster is Chief Chemist at Rotech Laboratories. He is M. Finger, R. Foucher, J. P. Husson, J. Jasaebski, interested in the history of science and in the evaluation of the A. Johnson, C. Sibille, R. Henck, R Regal, P. Siffert, thermodynamic and crystallographic properties of the elements.
Phtinum Metah Rev., 2000,44, (4) 178 ABSTRACTS of current literature on the platinum metals and their alloys PROPERTIES CHEMICAL COMPOUNDS Reduction of Pt(ll) by H2: Effects of Citrate and The Reactions of [M(dppe),l (M = Pd, Pt) with NaOH and Reaction Mechanism Elemental Selenium or Tellurium: Preparation and A. HENGLEIN and M. GIERSIG, J. Phs. Cbem. B, 2000,104, Structure of the Platinum Polyselenide (29), 6767-6772 Aged aqueous PtCb%solutions are reduced by HZin [PtSe4(dppe)l M. LE~AS,c. P. MOW and M. DI VAIRA, Polybednm, 2000, the absence of a stabiliser and in the presence of R sta- 19,0,751-756 bilising Na citrate or/and NaOH. The slowly formed colloidal Pt nanopartides were studied by hgh-reso- Reaction of pt(dppe)2] (1) (dppe = lJ-bis(di- lution electron microscopy. In dilute solutions, the pheny1phosphino)ethane) with Se, or of [PtCL(dppe)] rate of reduction was proportional to the square of with Li polyselenide, gave [ptSe4(dppe)]. Reaction of the Pt(Il) concentration. In the presence of citrate (1) with Te, followed by treatment with CHZCL, gave and NaOH, the reduction occurs more slowly. [Pt3(p3-Te)z(dppe)3]Clz. [Pd(dppe)Z] reacts with Se to give [Pd2(pSe)2(dppe)2] or [Pd~b3-Se)2(dppe)3lC1,, CuAlPd Alloys for Sensor and Actuator Applications depending upon the conditions. z. c.m, w. w, R H. ZEE and B. A. CHIN,Intmet&cs, 2000, 8, (=), 605-611 Synthesis and Utility of Novel Cmeso- CuAlPd alloys were found to have an austenite Glycosylated Metalloporphyrins transformation temperature range of 115-37OoC, and M. CORNIA, M. MENOZZI, E. RAGG, S. MAZZINI, A. SCARAFONI, hysteresis range from 17-85"C, depending on com- F. ZANARDI and G. CASIRAGHI, Tefrabedmn,2000,56, (24), position, heat treatment and working process. 3977-3983 Optimal shape memory properties were found for Gmemglycosylated porphyrins were prepared by Cu-13.1 wt.% Al-2.4 wt.% Pd. using either a dipyrrylmethane/aldehyde [2+2] cydo- condensation protocol, or a direct pyrrole/aldehyde The Effect of Alloying of Palladium with Silver and macrocydisation. When complexed with Pdo, and Rhodium on the Hydrogen Solubility, Miscibility fully liberated from the protecting groups, bis-uridinyl porphyrin and tetra-glycosylated porphyrin gave Gap and Hysteresis H20-soluble metallated species (1). (1) are efficient A. K. M. FAZLE KIBRIA and Y. SAKAMOTO, Int. Hydmgen J. DNA cleavers with visible hght at room temperature. Eneqy, 2000,25, (9), 853-859 The variation of H solubilities in Pd-5.0 and 10.0 YHalogenated Iridium(lll) Acetylacetonates at.% and Pd-5.0 and 10.0 at.% Rh alloys was stud- Ag v. G. ISAKOVA, I. A. BAIDINA, N. B. MOROZOVA and ied by a gas phase method. An increase of low I. K IGUMENOV, Po&edmn, 2000,19, (9), 1097-1103 pressure H solubility with increasing Ag content and a decrease of it with increasing Rh content occurs. Ir(acacx),,(acac)>,, (acacX = CH3COCXCOCH3, The plateau pressure (p+) of Pd-Rh-H had a remark- acac = CH3COCHCOCH3;n = 1,2,3; X = F, Cl, Br, ably higher value than that of Pd-Ag-H. Thehht value l) were prepared and purified. DTA and TGA studies decreased with increasing Ag content, whereas it showed the monosubstituted complexes to be the increased with increasing Rh content. Pd-10.0 atyo Ag- most volatile and disubstituted complexes to be less H showed the lowest loss of energy for hysteresis. volatile. The volatility of y-halogenated IrQIl) acetyl- acetonates is increased in comparison with the initial Insights into the Elimination of HCHO from the Ir(I1l) tris-acetylacetonate. Clusters [MdCO),&OOMe)l- (M, = RusC, m = 16; Structure and Magnetism in Pr3Ru07 M, = Rhs, m = 15) Provided by Electrospray Mass F. WISS, N. P. RAJU, k S. WILL3 mdJ. E. GREEDAN, ht. J. htg. Spectrometry Mdtcr., 2000,2, (l), 53-59 P. J. DYSON, N. FEEDER, B. F. G. JOHNSON, J. s. MCINDOE and The ordered fluorite, Prau07, (1) was synthesised P. R R LANGRIDGESMITH,]. Cbem Soc., Dalton Tmm., 2000, for the first time and its crystal structure was assigned (12), 181S1815 as Cmm. Relatively well separated zig-zig chains of The energy-dependent electrospray ionisation mass comer-sharing RuO6 octahedra were present. spectra of the methoxy adducts of the title hexanu- Magnetic susceptibility data of (1) show a Curie-Weiss dear dusters ~u&(cO)17]and [Rh6(co)16] have behaviour for T > 225 K with C = 5.96(4) emu K shown that loss of HCHO takes place during the mol-' and 8. = +11(2) K From the paramagnetic fragmentation processes. The differences in fragmen- regime, an effective magnetic moment was assigned tation patterns between the two clusters were to Ru(5+) which is shghtly reduced from the spin- correlated to their macroscopic chemical properties. only value, suggesting localised electrons at this site.
PLdmm Mefuh &., 2000,44, (4), 179-182 179 PHOTOCONVERSION Chemical Fluid Deposition: A Hybrid Technique Multiple ligand-Based Emissions from a for low-Temperature Metallization D.P. LONG, J. M. BLACKBURN and J. J. WATKINS, Adv, M&., Platinum(ll) Terpyridine Complex Attached to 2000,12,(12), 91S915 Pyrene I-hgh-purity films of Pt, Pd, Au and Fth have been J. F. MICHALEC, S. A. BEJUNE and D. R MCMILLIN, hOix. Cbem., deposited onto inorganic and polymer substrates by 2000,39, (13), 2708-2709 chemical reduction of organometallics in sc-CO2 Attachment of an electron-rich aryl substituent at using the chemical fluid deposition technique. A 180 the 4‘ position of 2,2’:6’,2”-terpyridine (trpy) in nm thick Rh film (1) was deposited onto Pd-seeded Pt(trpy)Cl’ endows the low-lying excited state with polyimide using [acac(Rh)(COD)] in sc-COZ and a intraligand charge-transfer character (ILCT), fortyfold molar excess of Hz at 60°C and 165 bar. (1) enhances the emission intensity, extends the excited- is polycrystalline and free of C contamination. state lifetime and inhibits exciplex quenching by Lewis bases. When pyrene is the substituent, the Surface Activation of Polyimide with Dielectric ILCT character of the absorption becomes dominant Barrier Discharge for Electroless Metal Deposition and the lifetime extends to 64 ps. H. ESROM, R SEEBOCK, M. CHARBONNIER and M. ROMAND, Su$ Coat. Tecbnol, 2000,125,(1-3), 19-24 Photophysical and Photoelectrochemical A novel activation process (1) for the electroless Properties of the Bis(2,2’-bipyridine)(4,4’-di- plating of non-conductive materials using a dielectric methylthio-2,2‘-bipyridine)ruthenium(ll) Complex barrier discharge (DBD) is reported. (1) is based on H. E. TOMA, R M. SERRASQUEIRO, R C. ROCHA, G. J. F. DEMETS, the plasma-induced chemical reduction at amospher- H. WINNISCHOFER, K. ARAKI, P. E. A. RIBEIRO and ic pressure in air of Pd acetate layers resulting in the C. L. DONNICI, J. Pbo~ocbem.Pbotabiol. A: Cbem., 2000,135, formation of Pd on non-active surfaces. Fast surface (2-3), 185-191 activation of polymers such as polyimide (2) occurs in [R~@ipy)~(Sbipy)]~+(Sbipy = 4,4’-dimethylthio-2,2’- only a few seconds using a simple DBD device. The bipydine) (1) exhibits strong charge-transfer bands DBD-induced Pd layers on (2) exhibit lugh activity at 450 nm and luminescence emission at 630 nm (tl/z with regard to initiation of electroless Cu plating. = 0.91 p).The thioether groups of Sbipy were used as strong binding sites for pentacyanoferrate ions, allowing immobilisation of (1) into Ni Prussian-blue APPARATUS AND TECHNIQUE type films. These display photoaction response to Highly Sensitive MISFET Sensors with Porous visible Ight in the presence of dissolved 02. R-Sn02 Gate Electrode for CO Gas Sensing Applications ELECTRODEPOSITION AND SURFACE H. FUKUDA. K. KASAMA and S. NOMURA, Sens. Actrrntors B, Cbem., 2000,64,(1-3), 163-168 COATINGS A new porous Pt-SnOz-gate MISFET gas sensor (1) Electrodeposition of Platinum from an Alkaline has been demonstrated for the detection of small Electrolyte amounts of CO. (1) combines the catalytic propetties s. s. DJOKI~,Ph. Swj Finirb., 2000,87, (5), 145-147 of Pt, and the spillover effect onto SnOz, with sur- Electrodeposition of Pt from an allraline electrolyte face-sensitive MISFETs. Using (l), it was possible to at 65°C gave smooth Pt coatings with cauliflower sur- detect 54 ppm of CO with a response time < 1 min face morphology. Uniform, crack-free coatings of Pt at 2PC. The good response indicates that (1) can be were obtained when the thickness was c 5 pm. Based used at a much lower temperature (27-100°C) than on XRD, the electrodepositedPt films were polycrys- can conventional solid-state gas sensors. talline with ciystallite size from 6-15 nm. Palladium-Modified Yttria-Stabilized Zirconia Preparation and Characterization of Platinum Membranes Black Electrodes J. KIM and Y. s. LIN, Ind. Eng. Cbem. Res., 2000, 39, (6). B. ILIC. D. CZAPLEWSKI, P. NEUZIL, T. STANCZYK, J. BLOUGH 21 242126 and G.J. MAWAY, J. Matw. Sci., 2000,35, (14), 3447-3457 Thin porous @a-stabilised zirconia (YSZ) mem- Deposition time and cure temperature were found branes (1) were moditied with Pd by the reservoir to influence the quality and morphology of electro- method. Multiple Pd impregnations inside (1) result- chemically deposited Pt black layers on evaporated Pt ed in a pore reduction and an increase in Pd electrodes. When the Pt black deposition time is < 60 concentration. He permeation experiments showed seconds, large voids were clearly seen throughout the that the average permeability decreased from 3.13 x electrode due to possible passivating contaminants. to 7.34 x 1(r6 mol/(m2 s Pa) after four Pd Non-uniform outgrowth of Pt black was observed for impregnations. XRD indicated that the prepared (1) deposition current densities > 100 mA ad.The had pure YSZ and Pd phases. The Pd phase became reproducibility of highly adherent platinised electrodes continuous after four impregnations, which was was achieved. confirmed by elecmcal conductivity measurements.
Pbtinnm Metals h.,2000, 44, (4) 180 Iridium-Based Electrocatalytic Systems for the Methyldecalin Hydrocracking over Palladium/ Determination of Insulin Zeolite-X M. PIKULSKI and w. GORSKI, Anal. Cbem., 2000, 72, (13), s. SAYAN, B. DWREL and J. PAUL, Fuel, 2000, 79, (11), 2696-2702 13951404 A homogeneous electrochemical catalytic system Studies of hydrocracking of methyldecalin over for the determination of insulin is based on the oxi- Pd/rare earth exchange X-type zeolite showed that dation of insulin by C1 complexes of IrO(1). The an increase in temperature from 325 to 350°C result- rate constants are equal to 25, 900 and 8400 1 mol-’ ed in a shift from the preferred cracking products to sd for the oxidation of insulin by Ii€&”, Ir@-I20)C15- aromatics, an enhanced amount of light hydrocarbon and II(H~O)~CL,respectively. Electroplating of off-gases, and a higher coverage of C residues (and a aquated (1) on glassy C electrode gave an IrO, surface lower coverage of reactant molecules). Pd is the agent film, which was used in a heterogeneous detection for Hz dissociation and repopulation of acid sites. system for insulin. Catalytic Dehydrogenation of Hydrocarbons in Amperometric On-Line Sensor for Continuous Palladium Composite Membrane Reactors Measurement of Hypoxanthine Based on Osmium- P. QUICKER, v. HOLLEINand R. DITTMEYER, Catal. Toiky, Polyvinylpyridine Gel Polymer and Xanthine Oxidase 2000,56, (1-3j, 21-34 Electroless Pd plating was confirmed to be a suit- Bienzyme Modified Glassy Carbon Electrode able method for coating ceramic supports. L. MAO and K. YAMAMOTO, Anal. Chim. Ada, 2000,415, Composite Pd-steel membranes could be prepared by (1-2), 14S150 high velocity oxy-fuel spraying and a combined An amperometric biosensor using Os-polyvinyl- method of electroplating and electroless plating. pyridine gel polymer (0s-gel-horseradish peroxide Coated membranes were employed for Hz separation (HFP)) and xanthine oxidase (XOD) bienzyme has in lab-scale membrane reactors during the dehydro- been developed for use in a thin-layer radial flow cell genation of ethylbenzene to styrene and propane to for on-line measurement of hypoxanthine (1). In propylene. The removal of Hz significantly increased continuous-flow amperometric experiments, Os-gel- the oletin yield, compared to the correspondmg HRP/XOD/glassy coated electrodes show linear and conventional packed-bed reactor results. sensitive responses towards (1) for concentrations of 0.5-80 pMwith a detection limit of 0.2 a. Palladium Catalysts on Activated Carbon Supports Influence of Reduction Temperature, Origin of the H ETER 0 G EN EO US CATALYSIS Support and Pretreatments of the Carbon Surface Highly Selective and Stable Multimetallic M. GURRATH, T. KURETZKY, H. P. BOEHM, L B. OKHLQPKOVA, Catalysts for Propane Dehydrogenation A. s. LISITSYN and v. A. LIKHOLOBOV, Carbon, 2000,38, (€9, 1241-1255 s. R. DE MIGUEL, E. L. JABLONSKI. A. A. CASTRO and O. A. Activated carbons produced from peat, coconut SCELZ~J. Chm. Technol Biotechnol., 2000,75,(7), 596-600 shell and by pyrolysis of hydrocarbons were treated Mono- (Pt), bi- (Pt-Sn, Pt-Pb, Pt-Ga) and trimetal- with 02, Clz, HZ or NH3 at elevated temperatures. Pd lic (Pt-Sn-Ga) catalysts based on Pt and supported on was deposited from anionic (HzPdCL), neutral A1203,AlzO, doped with K, and ZnAl204 were test- (Pd(OAc)zin acetone) and cationic (pd(NH3)4](NO&) ed in propane dehydrogenation (both in continuous complexes. Temperature-programmed reduction, CO and in pulse reactors) under severe process condi- chemisorption and ‘the olefin hydrogenation reaction tions. Pt-Sn-Ga/ZnAlz04 had a better and more were used to investigate the possible effects of prepa- stable performance (hgh yield to propene and low ration variables. The origin of the C support and the coke deposition), than the other bi- and trimetallic temperature of the catalyst reduction with HZ had systems and a commercial catalyst. most influence on the properties of the catalysts.
Poly(N-isopropylacry1amide)-GraftedSilica as a Polymer-Supported Ruthenium Porphyrins: Support of Platinum Colloids: Preparation Method, Versatile and Robust Epoxidation Catalysts with Characterization, and Catalytic Properties in Unusual Selectivity Hydrogenation X.-Q. YU, J.3HUANG. W.-Y. YU and C.-M. CHE,]. h.Chm. K. SUZUKI,T. YLTMURq M MIZUGUCHI, Y. TANAKA, C.-W. CHEN Joc., 2000,122,(22), 5337-5342 and M. AKASHI, J. Appl. Pohmer Jti., 2000, 77, (12), Carbonyl Ru(II) 5,10,15-tris(4-R-phenyl)-20-(4- 2678-2684 hydroxypheny1)porphyrins (R = Cl, Me) covalently Well-dispersed Pt colloids were synthesised in J-& on bonded to Merrifield‘s peptide resin were prepared. the surface of poly(Nisopmpylacrylamide)-graftedsil- These new heterogenised metalloporphyrin epoxida- ica via the reduction of PtChz by CzHsOH. The tion catalysts (1) exhibit a high versatility and stability. immobilised Pt colloids were active and stable hetero- (1) with R = C1 catalyse ClzpyNO epoxidation of geneous catalysts (1) for hydrogenation of ally1 alcohol alkenes such as aromatic and aliphatic terminal in CZH~OH.(1) are recyclable after centrifugation. alkenes and a,P-unsaturated ketones. (1) are reusable.
Phinum Metah h.,2000, 44, (4) 181 Microwave-Assisted Rapid Incorporation of Rhodium(1)-Catalyzed Addition of Phenols to Ruthenium into Lacunary Keggin-Type Dienes. A New Convergent Synthesis of Vitamin E Polyoxotungstates: One-Step Synthesis, 99R~, H. BIENAd,J.-E. ANC-P. MEILLAND andJ.-P.SIMONATO, Tetrabedm Left.,2000,41, (18), 3339-3343 NMR Characterization and Catalytic Activity A catalytic amount of pCl(COD)z], diphenyl- Of [PW~~O~~RU"(DMSO)]" phosphinobutane and K2C03 in toluene resulted in A BAGNO, M BONCHIO, A SARTORELand G. SCORRANO, Em the regioselective arylation of P-springene with 1. htg. Cbem., 2000, (l), 17-20 trimethylhydroquinone under mild conditions. [RuCl@MSO)4] was shown to react with the lacu- Further steps resulted in synthesis of vitamin E with nary tungstate hgand PW110391'- in HzO at 200°C an overall 50% yield. Other phenolic compounds and under microwave irradiation, leading to the complete 2-substituted-l,3-dieneswere also shown to undergo incorporation of a Ru atom into the polyoxomedlate this transformation. framework, and to the selective formation of the dia- magnetic, air-stable [pw,10~9Ru"(DMSO)I5 (1). (1) Hydroformylation Reactions in Supercritical exhibited remarkable catalytic activity in the presence Carbon Dioxide Using Insoluble Metal Complexes of NaI04 KHSOS in the oxidation of cyclooctene or M. F. SELLIN and D.J. COLE-HAMILTON, J. Cbem. Soc., Dolton and adamantane, respectively. Tmnr., 2000, (ll), 1681-1683 Rh phosphite catalysts (1) prepared in sitrr from 0 M0 G ENEO US CATALYSIS ~z(OAC)~]and P(OPh)3, P(OC~H~-~-C~HI~)~or H PhzPCH~CH(C0~C16H33)CH~CO~C1d+3,which are Palladium-Catalyzed Carbonylation of Aryl insoluble in SC-CO~,show high activity and excellent Halides -A Detailed Investigation of the linear selectivity in the hydroformylation of hex-l- Alkoxycarbonylation of 4-Bromoacetophenone ene. (1) can be recycled by flushing the products from w. MGERLEIN,M BELLER and A F. INDOLESE, J. MoA Cad the reactor using sc-COZ at the reaction temperature A Cbem., 2000,156, (1-2), 21S221 and pressure with no Rh leaching. The homogeneous Pd-catalysed alkoxycarbonyla- tion of Cbromoacetophenone with n-butanol to give A 14-Electron Ruthenium Hydride: the Key the corresponding benzoic acid ester (1) was investi- Intermediate in the Synthesis of Ruthenium gated. The highest catalyst efficiency was observed at Carbene Complexes; X-ray Structure of 130°C and low CO pressures using neat n-butanol as the solvent, NEt3 as the base and Pd(PPh& or [RuHCI( PPrt3)21 PdCl2(PhCN),/PPh3 as the catalyst precursor. A P. A. VAN DER SCHAAF, R. KOLLY and A. HAFNER, Cbem. strong dependence of the catalyst activity and stabili- Commun.,2000, (12), 1045-1046 ty on the phosphine concentration was found. A simple one-pot procedure for the synthesis of Ru Catalyst productivities (turnover number) of up to benzylidenes (Grubbs' catalyst) (1) has been devel- 7000 (70Y0yield of (1)) were achieved. oped, in which the key intermediate, a novel 14-electron Ru monohydride, [RuHC~(PPI'~)Z](2), is Microwave-Assisted, Solventless Suzuki Coupling prepared from [RuClz(cod)], 2 equivalents of PP93, and NEt3 in bowpropan-2-01 without the use of Reactions on Palladium-Doped Alumina Hz gas. (2) was reacted with HC1, an akyne and G. w. KABALK~R M. PAGNI, L. WANG, v. NAMBOODIRI and styrene to give (1). C. M. HAIR, Gnen Cbem., 2000,2, (3), 120-122 5% Pd/KF/Alz03 (1) has been used as the catalyst for solventless microwave-assisted Suzuki reactions FUEL CELLS of aryl halides with boronic acids and vinyl boronic A Study of Methanol Electro-Oxidation Reactions acids. (1) can be readily recycled via simple filtration. in Carbon Membrane Electrodes and Structural Other benefits include straightforward recovery of product, potential simple commercial scale up and Properties of Pt Alloy Electro-Catalysts by EXAFS T. PAGE, JOHNSON,J. HORMES, S. NODING and B. RAMBABU, low waste protocols due to the absence of solvents. R J Ekdmanul Cbem., 2000,485, (l),34-41 Transition metal alloy electrocatalysts (Pt-Fe/C, Pt- A Convenient Synthesis of Heteroaryl Benzoic Co/C, Pt-Ni/C, Pt-Cu/C) were evaluated as Acids via Suzuki Reaction potential alternatives to direct oxidation of DMFCs Y. GONG and H.w. PAW, $nk#, 2000, (6), 829-831 and compared with Pt group metal and alloy catalysts The Suzuki reaction was applied as a general one- using CV and X-ray absorption spectroscopy. Pt- step method for heteroaryl benzoic acid synthesis Co/C was found to be a better catalyst than the other from heteroaryl halides and carboxybenzeneboronic transition metal alloys. Pt/C/Nafion showed the acids. The coupling is carried out in the presence of highest resistance (lo6 R cm-3 compared with Pt- Pd(PPhS4 (1) and NazC03 in 50% aqueous acetoni- Ru/C (280 mC2 cm-3. The unfavourable electro- trile. A high yield was maintained when (1) was chemical performance of Pt-Ru can be correlated substituted by Pd(PPh3)KlZ and Pd(OAc)~/P(*tolyl)3, with the observed variations in geomeaic structural although prolonged reaction times were required. information obtained from EXAFS and XANES.
Plorwm Met& b.,2000,44, (4) 182 NEW PATENTS METALS AND ALLOYS ELECTRODEPOSITION AND SURFACE Metal Alloy Compositions for Jewellery COATINGS HARRY WINSTON INC. WOdd&L 00/22,180 Electroless Palladium Plating Liquid Metal alloy compositions used in the manufacture HITACHI CHEM. co.LTD. J@anese+pL 2000/129,454 of jewellery have a white finish consisting of (by Electroless Pd plating solution consists of a com- wto/): 95 Pt, 2.5-3.5 Rh and 1.5-2.5 Ru. The alloy plexing agent for Pd ions, with tetra-ammine Pd exhibits enhanced whiteness in comparison to Pt compounds as the Pd ion source, a reducing agent alloys available in the art. It does not require Rh such as formate, and a pH regulator. The plating plating to achieve an acceptable whiteness, thus velocity of Pd with this plating solution is excellent. increasing the ease of making the alloy, and reducing the cost of jewellery casts and settings. APPARATUS AND TECHNIQUE Alloy for Jewellery Nitrogen Oxide-Decomposing Electrode gIMA KIKINZOKU SEIREN KK NGK INSULATORS LTD. Eumpean +pL 1,006,352 Jqunese &L 2000/080,423 A NOx-decomposing electrode has a cermet elec- Au alloy for jewellety, such as rings, indudes (by trode composed of a Pt-Rh alloy (weght ratio of -at.%): 75-75.5 Au, 4-18 Pt, 2-11 Pd and 2-11 Ag. PtRh = 208&1:99) and a ceramic component. The The alloy excels in workability and hardness. The apparatus measures NOx concentration in atmos- corrosion resistance and antiwear quality are good. pheric air and exhaust gas discharged from vehicles, and may also contain an O2 pump to control the 02 concentration. Oxidation and reduction of Rh are ELECTROCHEMISTRY effectively suppressed, which allows suppression of Assembly for Separating Normal Water NOx adsorption at low temperature. K R OZCELIK Wodd+pL00/23,638 An internal combustion assembly for separating Catalytic Gas Detector normal H20into H2 and 02, and starihg a combus- EIC LAB. INC. U.S.Patmt 6,060,025 tion reaction, has a second winding that is added to A catalytic gas detector for measuring the concen- an alternator, and is provided with an anode of cylin- tration of organic gases in air comprises a drical structure made of Pt wires and a cathode made combustion sensor including a pellistor with a noble of compressed C powders. The level of HZO in the metal catalyst, which detects the gas concentration; a electrolysis container is controlled by a circuit. source of non-oxidising hydrocarbon-containing gas Maximum effiaency is obtained and the amount of (1) coupled to the combustion sensor; and a con- gases passed into the atmosphere is minimised. troller coupled to the sensor. The detector operates in detection and regeneration modes. In J-&U catalyst Wastewater Treatment regeneration occurs by heating in the presence of (1). KYUNGWON ENTERPRISE CO. LTD. Wd+pL 00/27,758 Solar Energy Devices An electrode for treating wastewater comprises a STARFIRE ELECTRONIC DEV. & MKTG. LTD. substrate coated with a multi-element electrode cata- U.S.Patmt 6,060,026 lyst comprises at least RuO2 and SnOz.The electrode A photoelectrochemical device (1) comprises a Si is cheap and durable, and has high 02overvoltage, domain, with a specified quantum excitation energy and can thus treat wastewater more effectively. The band gap to induce reaction, in electrical contact with electrode catalyst may be a three-element catalyst a first catalytic material, of Os, Ii or Ru, their oxides, composed of the oxides of Sn-Pt-Ru, and the novel chalcogenides, etc. (1) uses solar energy to drive elec- substrate is a ceramic Ti407. trochemical reactions, to react a molecule using hght as an energy source and catalyst material, to decom- Chlorine Production pose H20, and to degrade pollutants. (1) has good E. I. DU PONT DE NEMOURS & co. U.S. Putmt 6,066,248 stability in corrosive solutions. Chlorine is produced by electrolysis of an aqueous solution of HC1 in an electrochemical flow reactor Resistor Slide Sensor consisting of a solid polymer electrolyte membrane; TOYOTA JIDOSHA KK Jqanese +pL2000/111,309 an anode comprised of an ionomer and a catalyst A resistor slide-type rotation angle sensor for a material selected from Pt, Ru, Os, Rh, It, Pd, Re, Au, potentiometer, has slider units (1) formed with Pd- Ti, Zr, and their oxides, alloys and mixtures; and a Ag alloy, I 18 wt.% each, in contact with resistors. (1) cathode. The anode and cathode may be on the mem- has comb tooth in a point. The cross-section of (1) brane. HC1 solution is fed to the anode. Electrolysis has a groove of parabolic shape so that abrasive pow- using hgh current densities and low cell voltages, der falls easily into the groove. The quantity of minimises side reactions, such as 02generation. abrasive powder remaining on a resistor is reduced.
PLdnum MhLr Rm.,2000,44, (4), 1E-186 183 HETE R 0 G ENE 0 US CATALYSIS Selective Hydrogenation of Benzene Nitrogen Oxide-Storage Catalyst CHINESE PETROLEUM COW. U.S. Patent 6,060,423 A catalyst (1) for the selective hydrogenation of DEGUSSA-HUELS A.G. Eumpean Appl. 993,860 A NOx-storage catalyst used in exhaust gas purifi- benzene to cyclohexene (2) comprises a Group VIII cation from lean burning automobiles has at least one metal, preferably Ru, supported on a binary G-Zn fine particled catalyst, such as Pt or Rh on active oxide, in which the atomic ratio of Ga:Zn is 1:l-5. (1) AlzO,, CeOz and/or ZrO,, and a NOx-storage com- gives a high selectivity and yield in the production of ponent, with particle diameter of < 1 pm of Ba (2). and allows mass production of (2). (2) is useful as and/or Sr sulfates or their mixture. The catalyst has a starting material for the manufacture of pharma- ceuticals, foods, agrochemicals, animal feeds and improved ageing stability and can be coated on the walls of the flow canals of inert honeycombs. nylon 66 (via adipic acid).
Emission Control for Diesel Engine Exhaust Catalytic Reforming of Hydrocarbons CHEVRON CHEM. CO. LLC 6,063,264 JOHNSON MAlTHEY PLC WorkiAppL 00/21,647 U.S.Patent A method for controlling emissions from diesel Catalytic reforming of feed hydrocarbons into aro- engine exhaust, comprises a catalyst to convert NO matics involves contacting the feed under catalytic to NO,, a filter to trap soot and hold it for combus- reforming conditions with catalyst disposed in the tion with the NOz, and a NOx absorber (1). The tubes of a furnace. The catalyst is monofunctional catalyst, which is associated with or follows (l), con- and non-acidic, comprising a Group VIII metal (Pt) tains Pt group metal@)supported on VzOs/TiOz. (1) and zeolite L. The furnace tubes have an inside diam- can be regenerated by decreasing the net oxidant level eter of 2-8 inches and are heated by gas or oil burners and injecting a NOx-reductant upstream. During located outside the tubes. The process is simplified regeneration, the exhaust gases leaving the absorber and requires significantly less capital equipment than are passed through a three-way catalyst. The process conventional catalytic reforming systems. meets the European Stage IV emission legislation. Sulfur-Tolerant Pt/L-Zeolite Catalyst Catalytic Composition for Unsaturated Hydrocarbons UNIV. OKLAHOMA STATE U.S. Patent 6,063,724 PHILLIPS PETROLEUM CO. WorkiAppL 00/23,403 S-tolerant Pt/Gzeolite catalyst (1) is prepared by A catalyst composition (1) for use in the selective modifying substantially anhydrous L-zeolite with rare hydrogenation of an unsaturated hydrocarbon, such earth ion(s), calcining the latter, and then associating as akynes or diolefins, comprises Pd, an inorganic a Group VIII metal with the modified L-zeolite. (1) support, and a selectivity enhancer comprising P, a P is used for the conversion of (cyc1o)aliphatic hydro- compound, S and/or a S compound. In the presence carbons, and for reforming, dehydrogenating, and of (1) and Hl, highly unsaturated hydrocarbons are aromatising aliphatic and/or cycloaliphatic hydrocar- converted to less unsaturated hydrocarbons. Using bons. The increase in S tolerance results in increased (1) decreases production of the oligomers that form conversion and selectivities. green oils which decrease the life cycle of (1). Monolithic Catalyst for Purification of Exhaust Gas Exhaust Gas Purification NISSAN MOTOR CO. L’D. Japanese AppL 2000/093,799 TOYOTA JIDOSHA KK. WorkiA$pL 00/27,508 A monolithic catalyst (1) for the purification of Exhaust gas purification of hydrocarbons, CO and exhaust gas emitted from I.C.E. has a bed supporting NOx from I.C.E. is performed by contacting low catalytic constituents, and contains Pd and aluminate hydrocarbon-containing exhaust gas with an oxida- powders of formula (X),(Y)&Od where X = Co, Ni tion-reduction catalyst which comprises Rh and/or and/or Zn; Y = Ce and/or Zr; a, b, c and d = atom- Pd supported on an Oz ocduding and releasing mate- ic ratios; when c = 2.0, a = 0.1-0.8, b = 0.0014.3, rial. The emission of hydrocarbon is greatly inhibited and d = number of 0 atoms to satisfy the valence of over a wide range from low temperature to high tem- each constituent. (1) can also contain La, Nd and Zr, perature. The activity of the catalyst is improved. and CeOZ. (1) has low temperature activity and cat- alytic activity in any exhaust gas atmosphere. Reforming Naphtha Feedstock UOP LLC U.S.Patent 6,048,449 Exhaust Gas Purifier A naphtha feedstock is contacted with a dual func- ZEXEL KK Japanese AppL 2000/104,540 tion catalyst (1) comprising a refractory inorganic An exhaust gas purifier for I.C.E. has a microwave oxide support combined with a multigradient metal absorber comprising Pt, Rh, Pd as catalyst material component containing (in mass Yo):0.01-2 Pt group which is configured in a cavity resonator and adjusts metal, 0.1-5 In, 0.01-5 Group IVA metal and 0.1-10 impedance to set reflecting elecmc power ratio to 2 halogen, at 425-565°C and 350-2500 kPa. The con- 10 dE3. A honeycomb-like metal is configured beside centration of the Pt group metal in the surface layer the microwave absorber and cavity resonator and of (1) is 2 5 times higher than in the central core. (1) made to conduct electrically via the casing. has improved activity, stability and selectivity, and an Microwaves are absorbed effectively, so the catalyst improved gasoline yield is obtained. can quickly reach its operating temperature.
Phhhm MefuL Fh,2000, 44, (4) 184 Palladium-Carrying Zeolites Methanol Carbonylation NIPPON OIL co. LTD. Japanese AppL 2000/126,602 ACE- CHIM.SA. WorkiAppL 00/27,785 Production of Pd-carrying zeolite casting catalyst The addition of Pt to the Ir- or Ir/Rh-based cat- (l), where the zeolite is preferably mordenite, alytic system for the production of acetic acid and/or involves making zeolite pellets, with binder, to carry methyl acetate by the carbonylation of methanol and Pd and performing rapid drying with hot air, after isomerisation of methyl formate, results in an preprocessing in aqueous NH,. (1) is used for con- improved, continuous, liquid phase. The reaction is version reactions of hydrocarbons, such as performed in the presence of HzO, a solvent, the hydrogenation, isomerisation and disproportionation. homogeneous catalyst system, a halogenated promot- The Pd load can be dispersed with high uniformity er and CO. Improved productivity is obtained. between pellets and within each pellet (1) has long Me and high activity in the above reactions. Hydroformylation of Olefins SHELL OIL co. U.S. Patent 6,031,506 Destruction of Organochlorine Pollutants in Water A hydroformylation process for converting olehs ATE ANTIPOLLUTION TECH. ENTREPRISE to aldehydes and alcohols uses a combination of a Fmch AppL 2,184,981 source of Pd, Pt or Ni; a bidentate ligand; and an acid A process for destroying chlorinated pollutants in a promoter. An olefinic feed is reacted with HZand CO phreatic (pollutant-saturated) H20 layer comprises in a catalyst system of Pd, diphosphine ligand, HzO contacting the HzO layer with a catalyst comprising and a promoter such as formate, formic acid or a Pd supported on a synthetic or ~tuialzeolite. The formic acid forming reagent that is not an orthofor- process is useful for treating water contaminated with mate. The process does not damage or destroy the chlorinated solvents, such as trichloroethylene, chlo- reactors or vessels and results in &h conversion/ rinated aromatic compounds, such as chlorobenzene, high selectivity reactions with excellent reaction rates. and/or plant protection agents, such as Lindane or Dinoterbe. A wide range of organic pollutants can be degraded by changing the hydrophobicity of the FUEL CELLS zeolite supports by selecting a suitable A1:Si ratio. Carbon Monoxide Oxidation Catalyst IDEMITSUKOSAN co.LTD. WorkiAppL 00/30,745 Hydrogenation of Aromatic Amines A CO oxidation catalyst, useful in the production BAYER A.G. GmanAppL 1/98/45,641 of Ha-containing gas, comprises Ru and optionally A process for the hydrogenation of aromatic alkali metal and/or alkaline earth metal supported on amines to symmetrical dicycloaliphatic amines pro- TiOz and MZO3.CO poisoning of the Pt/Hz elec- ceeds with high selectivity and hgh conversion at trode of a Hz-02 fuel cell is prevented. The CO in the 0.5-50 bar on base-treated, supported Pt gioup metal Hz-containing gas is selectively removed over a broad catalysts. The support is coated with salts or oxides of temperature range. The lifetime of the cell and the Cr, Mo, W, Mn and/or Re, impregnated with Rh and stability of the discharge are improved. optionally with Ir, Ru, Os, Pd and/or Pt, then treat- ed with base. The base is completely or partly Improving Fuel Cell Performance neutralised by hnal impregnation with a soluble acid. BALLARD POWER SYSTEMS INC. Warki&Lr. 00/24,0123 The performance of a liquid feed SPEFC is HOMOGENEOUS CATALYSIS improved by impregnating the electrode substrate High Purity Organopolysiloxanes with a first proton conducting ionomer, then applying DOW CORNING COW. European AppL 995,771 the electrocatalyst such as Pt-Ru (1) to the impreg- High purity oxyalkylene-modified organopolysilox- nated substrate, or by oxidising the carbonaceous anes useful in cosmetics are prepared by reacting substrate prior to incorporation of (1). The electrode vinyloxy polyoxyalkylene compound and organohy- is supplied with a liquid reactant stream. The ionomer drogensiloxane compound in the presence of a Pt coating reduces the tendency of (1) to penetrate the group metal-containing catalyst (1). The organopoly- substrate and keeps (1) localised at the substrate/ siloxanes are free of unwanted odour and do not membrane interface in the MEA. Better transport of contain excess polyoxyalkylene compound since the reactants and products is achieved. vinyloxy polyoxyakylene compounds are not prone to isomerisation during the reaction. Solid Polymer Electrolyte Membranes JOHNSON MATI'HEY PLC WoridAppL 00/24,014 Production of lsobutylene Glycol The preparation of a solid polymer electrolyte MITSUBISHI GAS Cm.co. mc. Empan A@L 1,010,682 membrane, comprised of an ion-conducting polymer, Isobutylene glycol (1) is produced by the reduction a precious metals catalyst, such as Pt, and a hgh sur- of methyl hydroxyisobutyrate using a catalyst com- face area support, is claimed. Also disclosed is the prising Cu and/or Ru components. The catalyst is preparation of a membrane electrode assembly and a more selective than prior art and produces (1) in fuel cell. The process is less complex, has fewer and higher yields. (1) is useful as a raw material in the pro- shorter steps, with consistent results. Lower amounts duction of polyester films, resins and solvents, etc. of catalyst are used more effectively.
PlJinwm Me.+& Rm, 2000,44, (4) 185 Nanocrystalline Particles lor Fuel Cell Electrodes Organic Electronic Package FARADAY TECHNOLOGY INC. worki&pL 00/28,114 INT. BUSINESS MACHINES COW. U.J. Patent 6,025,057 Nanocrystahe particles (3-8 nm) of Pt, Pd, Ru An electronic package for chip carriers, printed cir- and/or Rh or their alloys (l), are electrodeposited on cuit boards and cards, accessory cards, etc., consists a substrate by immersing an electrically conductive of an organic substrate, with a hrst conductive circuit. substrate and a counter electrode in an electroplating On top of this is stacked a photoimageable dielectric, bath; then passing a pulsed electric current. The cata- an organic polyelectrolyte, a Pd-Sn seed layer (of Pd lyst layer is 0.1-15 p thick and the catalyst loading coverage < 8 pg mi2and Sn coverage < 2 pg cn?), is 0.1-1.0 mg cm?. Due to the contact of (1) with the and a second conductive circuit. The polyelectrolyte solid electrolyte and the electroconductive support, is catalytic for forming the Pd-Sn seed layer which is effective catalysis of the fuel cell reactions is assured. catalytic for Cu deposition.
Solid Oxide Fuel Cell Sputtering Material for Thin Film INT. BUSINESS MACHINES COW. FURUYA IUNZOKU KK Japanese AppL 2000/109,943 U.J. Putents 6,051,173 and 6,051,329 A sputtering material for thin film formation, use- A SOFC (1) with controlled porosity is produced ful for optical recording media, contains AgPd alloy by forming anode, electrolyte, cathode and intercon- (1) having 0.5-4.9 Yo of Ag and Pd. (1) provides a nect layers from laminated materials. The layers high reflecting rate and improves the weather resis- comprise unsintered ceramic material with Pt, Rh tance of the optical recording medium. The and/or Ru catalyst. The laminate is then sintered in a deterioration of the reproduced signal is prevented neutral or reducing atmosphere. (1) generates elec- for a long term. The thin film formed using the sput- tricity from fuel gas and air. The catalytic anode has a tering target produces the reflecting rate 2 88% at low operating temperature and high efficiency in wavelength < 800 nm. reforming fuels without carbonaceous residues. Strontium Ruthenate Sintered Compact Solid Polymeric Type Fuel Battery KYOCERA CORP. Japanese &pL 2000/128,638 TOSHIBA KK J@anese AppL 2000/133,283 A Sr ruthenate sintered compact (1) for use as a A solid polymeric type fuel battery for space vehi- sputtering target for forming dielectric films has spe- cle use has gas diffusion electrodes on both sides of cific density 2 3.5 g ~m-~,and contains molar ratio of a solid polymer electrolytic film. Catalyst layers of Pt Sr:Ru of 1.1-1.3. (1) is made by the calcination of or Ru are coated on the electrode surface which con- srco3 and Ru02 to form a Sr-Ru calcined powder, tacts the surface of the electrolytic film. The contact which is moulded to a specific shape and baked to area of the electrode and the film is set to 2 0.005 m‘ form (1). Dielectric film is formed when high density cm-’ of electrode. (1) is used as the sputtering target. Spin Valve Magneto-Resistive Head ELECTRICAL AND ELECTRONIC YAMAHA CORP. lapanese AppL 2000/132,820 ENGINEERING A spin valve magneto-resistive head includes a Metallised Ceramic Magnetic Device magnetic fixing layer containing an antiferromagnetic LUCENT TECHNOLOGIES INC. Eumpean A&pL 1,017,068 film (1) made of a Pt-Mn alloy, or Pt and Mn, having A metallised ceramic magnetic substrate device (1) the film thickness set to 20-35 nm. A spacer-layer is produced by coating an unfired ferrite substrate magnetic film and a magnetic fixing layer containing with conductive material of Ag/Pd and 10-50 wt.% the rigid Pt-h4n antiferromagnetic film are sequential- ferrite particles, cellulose or other organic binder and ly formed on a soft magnetic freedom layer. Loss of solvent, hdng the substrate, and electroplating Cu sensitivity at high temperature is prevented. onto the conductive material via a Cu pyrophosphate bath. High pull strengths are obtained due to the improved conductive coating. (1) is used to produce MEDICAL USES inductors, transformers and magnetic substrates. Passage Opening Medical Stent W. C. HERAEUS G.m.b.H.& CO. K.G. Cathode Material lor Electron Emission Gman AppL 1/99/06,417 A passage opening support structure, especially a NIKOS-ECO LTD. WarkfAppL 00/21,110 A cathode material (1) for emitting electrons in medical stent, has a Au layer between a special steel electron beam devices and cathode-ray tubes, substrate and a Pt surface layer (1) of thickness 0.1-1.0 pn. (1) provides the required biocompatibili- includes in wt.%: 0.5-9.0 of a rare earth metal of the while the Au layer withstands mechanical loads, cerium group, 0.515 W and/or Re, 0.5-10 Hf and ty especially bending and torsion forces during stent remainder Ir. (1) is prepared by melting Ir and Ce to widening, to avoid crack formation in the Pt layer. form IrsCe, melting Hf and W to form Hf3W and Iinally melting the formed IrsCe and HfiW to prepare an ingot of (1). (1) has excellent electron-emissiveand The New Patents abstracts have been prepared from mechanical properties and longer useful life. material published by Denvent Information Limited.
Pkadnum Metah Rev., 2000,44, (4) 186 NAME INDEX TO VOLUME 44
Page Page Page Page Abe, T. 44 Bhanage, B. M. 138 Chen, Q. 32 Dodd, J. 139 Ahn, B. S. 138 Bianchini, C. 44 Chen, W. 136 Donaldson, K. 73 Akashi, M. 181 Bickley, J. F. 136 Chen, Y. 42 Dong, S. 32 Akermark, B. 85 BienaymC, H. 182 Cheung, K.-K. 40 Dong, X. 32 Aldaz, A. 86 Biggs, T. 57 Cheung, N. W. 89 Donnici, C. L. 180 Amendola, S. C. 140 Binder, M. 140 Chi, G. C. 157 Dragutan, I. 58, Ancel, J.-E. 182 Biradha, K. 41 Chiba, A. 107 112, 168 Andersson, J. 72 Birdwell, A. G. 135 Chin, B. A. 179 Dragutan, V. 58, Andrews, L. 40 Birkin, P. R. 86 Ching, J. 31 112, 168 Ang, L.-M. 42 Birss, V. I. 86 Cho, Y. 89 Dubois, J. M. 135 Antonov, V. N. 135 Blackburn, J. M. 180 Choi, C.-S. 157 Dubovoy, T. 66 Arai, M. 135, 138 Blanco, G. 124 Choi, E.4. 137 Duncombe, P. R. 107 Araki, K. 180 Blough, J. 180 Choi, J.-C. 139 Diirr, H. 136 Aranda, D. A. G. 138 Blum, J. 43 Choi, Y. C. 140 Dyson, P. J. 179 Aranzabal, A. 138 Bock, C. 86 Chu, S. N. G. 157 Arblaster, J. W. 173 Boehm, H. P. 181 Chuang, K. T. 43 Aschi, M. 87 Bonchio, M. 182 Chuo, C. C. 157 Edwards, R. 72 Asbton, S. V. 2, 14,55, Bond, G. C. 146 Chyi, J.4. 157 Ehrhardt, G. J. 50 105, 118, 166, 172 Bonet, F. 39 Clarke-Sturman, A. 73 El Khakani, M. A. 42 Ashworth, T. V. 56 Bonetti, Y. C. 138 Coffey, K. R. 40 Elding, L. I. 140 Attard, G. S. 86 Bouquillon, S. 88 Cole-Hamilton, D. J. 182 Elliott, J. M. 86 Auner, G. W. 137 Bovin, J.-0. 11 1 Cornia, M. 179 Epifani, M. 87 Averbuch-Poucbot, Boyd, D. 120 Cornils, B. 167 Ermakov, A. 106 M.-T. 88 Boyd, I. W. 42 Cornish, L. A. 56,85 Esrom, H. 180 Bracchini, C. 89 Corti,C. W. 156 Bravaya, N. M. 15 Cottington, I. E. 30.56 Badding, J. V. 55 Brillas, E. 41 Coville, N. J. 56 Fang, M. 14 Bagno, A. 182 Bronstrup, M. 87 Cvakka, J. 87 Faraglia, G. 40 Baidina, I. A. 179 Bryson, T. A. 138 Czaplewski, D. 180 Fazle Kibria, Baiker, A. 88 Bullington, J. 139 A. K. M. 179 Bajt, S. 140 Feeder, N. 179 Baker, G. 57 Daly, D. J. 42 Fehrmann, B. 86 Balaban, A. T. 58, Cabot, P. L. 140 Dang, G. T. 157 Fei, Y. 55 112, 168 Cabral, C. 107 Datt, M. S. 140 FernPndez, J. 86 Balasubramaniam, Calpe, J. C. 140 Daum, J. 84 Ferret, R. 138 R. 135 Campbell, M. 42 David,S.A. I06 Fierro, J. L. G. 43 Baldo, M. 66 Cao, X. A. 157 De Miguel, S. R. 181 Flanagan, T. B. 135 Balk, T. J. 106 Capone, S. 87 De Rossi, S. 89 Folks, L. 135 Balmes, 0. 111 Carter, R. 156 Demets, G. J. F. I80 Fonda, R. W. 85 Barbaro, P. 44 Casado, J. 41, 140 Demirel, B. 181 Fornasiero, P. 124 Barbier, J. 137 Casiraghi, G. 179 Dempster, A. J. 175 Forrest, S. R. 66 Barek, J. 87 Castello, P. 40 Deng, D. 31.32 Fort, Y. 135 Barmak, K. 40 Castro, A. A. 181 Dermody, D. J. 14 Fortini, A. J. 106 Bartlett, P. N. 86 Cawthorn, R. G. 56 d’Hardemare, Francib, G. 44 Basura, V. I. 44 Centi, G. 84 A. du M. 88 Francois, V. E. 56 Batz, V. 43 Cha, S. Y. 89 Di Vaira, M. 179 Fraser, C. S. A. 118 Bauta, W. 139 Chaker, M. 42 Diefenbach, M. 87 Fregona, D. 40 Beattie, P. D. 44 Charbonnier, M. 180 Dijkstra, H. P. 41 Freye, H. 157 Bejune, S. A. 180 Charmant, J. P. H. 89 Ding, H. R. 32 Friedrich, A. 73 Beller, M. 44, 182 Che, C.-M. 181 DiSalvo, F. J. 55 Fujisaki, Y. 140 Bentley, R. E. 137 Cben, C.-W. 181 Dittmeyer, R. 181 Fuknda, H. 180 Bernal, S. I24 Chen, K. Y. 42 Djokif, S. S. 180 Furlani, A. 40
PLdimm Me& Rm, 2000,44, (4), 187-190 187 Page Page Page Page
Garcia, M. T. 140 Hair, C. M. 182 Ilic, B. 180 Kim, D. C. 42 Garcia-Fresnadillo, Hamada, T. 89 Illan-Gomez, M. J. 135 Kim, H.-D. 42 D. 42 Hamill,A. 42 Illy-cherrey, S. 135 Kim, J. 180 Gaiparovicovi, D. 43 Han, J. 157 Indolese, A. F. 182 Kim,% 40 Gauthier, D. 139 Han,M. 42 Indovina, V. 89 Kinloch, E. D. 33 Gavagnin, R. 84 Han, W. 31 Ingo, G. M. 156 Kiuchi, H. 32 Gehremariam, S. 137 Hangas, J. 137 Iniesta, J. 86 Koch,M.G. 43 Georg, A. 155 Hansen, L. B. 135 Ioannides, T. 87 Koistinen, K. 72 George, E. P. 107 Harada, H. 107 Isakova, V. G. 179 Kolly, R. 182 Geresh, S. 88 Harman, W. D. 139 Ishikawa, A. 136 Konsolakis, M. 43 Ghaffar, T. 89 Harris, J. E. 30 Korsgren, J. G. 85 Ghanbaja, J. 135 Harrison, R. 72 Kozuh, P. A. 74 Ghosh, G. 86 Hayashi,H. 89 Jahlonski, E. L. 181 Kralik, M. 43 Gibson, J. M. 138 Haynes, A. 89 Jacobs, P. A. 44 Kulikov, A. V. 15 Giersig, M. 179 He,X. 32 Janjua, M. S. 140 Kumamoto, K. 89 Gignoux, D. 85 Henglein, A. 136, Jeitschko, W. 86 Kunkely, H. 41, 136 Giorgi, L. 89 166, 179 Jenkins, H. A. I 18 Kupferman, K. 43 Gleeson, B. 40 Henin, F. 88 Jennings, J. M. 138 Kuretzky, T. 181 Gohrecht, J. 138 Henrion, W. 135 Jennings, M. C. 118 Kushida-Ahdelghafar, Gbmez, R. 43 Herrera-Urhina, R. 39 Jeon, S. G. 138 K. 140 Goncharov, I. I. 74 Herrmann, W. A. 167 Jepsen, 0. 135 Kwong, R. C. 66 Gong, Y. 182 Hershkovitz, M. 88 Jia, W. 50 Gonzalez, J. M. 137 Herwig, J. 44 Jiang, F. 41 Gonzalez-Garcia, Hickey, N. 124 Jiang, Y.-Y. 87 Laing, M. 56 J. 86 Hill, P. J. 56, 85, Jo, W. 42 Lamhert, R. M. 43 GonzPez-Marcos, 107, 158 Jockusch, S. I36 Lamhert, S. 39 J. A. 138 Himori, A. 85 Johnson, B. F. G. 179 Lan, X. 32 Gonzilez-Velasco, Hmatsu, Y. 40 Johnson, R. 182 Lan, X. Z. 32 J. R. 138 Hoegaerts, D. 44 Johnston, P. 167 Lanam, R. D. 107, 156 Gorski, W. 181 Holdcroft, S. 44 Jones, C. D. W. 55 Landau, M. 88 Gottlieb, M. 88 Hollein, V. 181 Jones, H. N. 85 Laugridge-Smith, Granozzi, G. 87 Holmes-Smith, A. S. 42 Jones, J. H. 94 P. R. R. 179 Gray, P. G. 108 Holzwarth, A. 16 Jones, R. T. 56 L’Argentikre, P. C. 86 Graziani, M. 124 Hor, T. S. A. 42 Job, F. 44 Larson, D. J. 40 Greedan, J. E. 179 Hormes, J. 182 Jun, J.-H. 157 Lautens, M. 138 Greenway, G. M. 137 Horner, I. J. 56 Jung, M.-C. 42 Laws, M. J. 56 Grill, A. 107 Hoshino, Y. 41 Jurisson, S. S. 50 Le Drogoff, B. 42 Grimwade, M. 156 Hosoda, H. 107 Leasure, R. M. I36 Grossi, J. 106 Hosono, H. 41 Lee, B. S. I40 Grove, D. M. 41 Howard, J. K. 40 Kahalka, G. W. 182 Lee, C. A. 33 Grugeon, S. 39 Hronec, M. 43 Kachi, T. 140 Lee, C.-M. 157 Gryn, G. I. 74 Hsu, S. T. 89 Kadarkaraisamy, Lee, H. 138 Gu, Y. F. 107 Huang, J.-S. 181 M. 136 Lee, H. M. 44 GuCrin, M. 137 Huang, M.-Y. 87 Kalman, E.-L. 57 Lee, W. M. 89 Guezala, E. 140 Huher,T. 111 Kaneko, M. 44 Leitner, W. 44 Guilhault, G. G. 42 Hughes,R. 43,85 Kapoor, M. P. 88 Lemma, K. I40 Guimariies, A. L. 138 Husehye, S. 136 Karlsson, G. 111 Leo, G. 139 Gurrath, M. 181 Kasama, K. 180 Leong, W. K. 41 KaSpar, J. 124 Leszczynski, J. 88 Ihusuki, B. 89 Kawamura, A. 138 Lewtas, M. R. 179 Hafner, A. 182 Ichikawa, M. 3 Kawasaki, M. 32 Li, A. 43,85 Hagelin, H. 85 Igeta,K. 135 Kelly, M. T. 140 Li, G. 31.32 Hagihara, Y. 41 Iguchi,M. 32 Ketring, A. R. 50 Li, H. 32 Hahnlein. M. 84 Igumenov, I. K. 179 Kikuchi, E. I38 Li, K. 32
Phhnrcm Metah h.,2000, 44, (4) 188 Page Page Page Page Liang, W. 43.85 Matsumura, Y. 88 Neusse, E. W. 56 Petillo, P. J. 140 Licciulli, A. 87 Matsunaga, M. 137 Neuzil, P. 180 Pettersson, Licini, M. 41 Mazzini, S. 179 Nicol, M. J. 106 J. B. C. 85 Likholobov, V. A. 18 1 McCarthy, J. M. 44 Nishiyama, M. 88 Piguel, S. 138 Lin, C. 41 McCool, B. 43 Nissenbaum, A. 137 Pikulski, M. 181 Lin, J. T. 85 McCreedy, T. 137 Noding, S. 182 Pinhas, A. R. 172 Lin, K.-J. 85 McDonnell, P. 139 Nomura, S. 180 Pinna, F. 84 Lin, Y. S. 43, 180 McEwan, B. 72 Normandeau, G. 157 Pirault-Roy, L. I37 Lin, Z. C. 179 McIndoe, J. S. 179 Noronha, F. B. 138 Polvani, D. A. 55 Linares-Solano, A. 135 McKamey, C. G. 107 Norrby, P.-0. 85 Pomeroy, R. K. 41 Lisitsyn, A. S. 181 McMdin, D. R. 180 Nmskov, J. K. 135 Pomogailo, A. D. 15 Liu, S. 32 McNamara, J. M. 71 Nukaga, M. 44 Popov, B. N. 41 Liu, W. 31 Meilland, P. 182 Prins, R. 138 Liu, X. 32 Meli, A. 44 Prior, A. 31 Liu, X.-X. 136 Meng, J. F. 55 Oge, M. T. 72 Priisse, U. 84 Lofvendahl, A. 57 Menozzi, M. 179 Ogura, M. 138 Puddephatt, R. J. 118 Long, D. P. 180 Meyer, T. J. 136 Ohizumi, W. I35 Loose, T. 106 Michalec, J. F. 180 Ohnishi, S. 89 Qijun, S. 137 Lbpez, T. 43 Miki, E.-I. 136 Ohriner, E. K. 107 Quaranta, F. 87 Lbpez-Fonseca, R. 138 Mine, T. 140 Okada, F. 72 Quicker, P. 181 Lundstrom, I. 57 Mitkin, V. N. 106 Okafor, V. I. 56 Quitoriano, N. J. 89 Lupton, D. F. 106 Mizuguchi, M. 181 Okhlopkova, L. B. 181 Lutz, M. 41 Modaferri, E. 84 Opara Kraiovec, Radulescu, F. 44 Lyon, L. A. 14 Moneti, S. 44 U. 155 Ragaini, J. D. 106 Monteiro, R. S. 138 Opekar, F. 87 Ram E. 179 Montiel, V. 86 Orel, B. 155 Raju, N. P. 179 Ma, D. 50 Moreno-Bondi, Orellana, F. 43 Rambabu, B. 182 Ma, X. X. 32 M. C. 42 Orellana, G. 42 Rambla, J. 41 Maa, J.4. 89 Morikita, T. 89 Ortelli, E. E. 87 Raw, P. 156 Mabry, J. M. 139 Morimitsu, M. 137 Osakada, K. 139 Rebien, M. 135 Maclay, G. J. 180 Morimo, R. 89 O’Sullivan, C. K. 42 Reetz, M. T. 43 Macleod, N. 43 Morioka, Y. 136 Otogawa, R. 137 Reiss, B. D. 14 Macpherson, J. V. 2 1 Morley, C. P. 179 Ott, D. 157 Rella, R. 87 Maerz, J. 156 Morozova, N. B. 179 Otto, s. 140 Rempel, G. L. 139 Magerlein, W. 182 Morris, G. E. 89 Oya, A. 135 Ren, F. 157 Magrin, A. 87 Moser, A. 135 Ozaki, J. 135 Reyes, P. 43 Maier, W. F. 16 MOSS,J. A. 136 Ribeiro, P. E. A. 180 Maire, F. 137 Mshewa, M. M. 157 Rimai, L. 137 Maitlis, P. M. 89 Mukasyan, A. S. 137 Page, T. 182 Ristau, R. A. 40 Mallouk, T. E. 14 Mukhopadhyay, S. 87 Pagni, R. M. 182 Ritter, J. A. 41 Malm, J.-0. 111 Murahashi, S.4. 139 Pallassana, V. 135 Rizzi, G. A. 87 Maniguet, S. 139 Murray, C. B. 135 Pan, Q.-C. 31 Rocha, R. C. 180 Mao, L. 181 Muzart, J. 88 Panfilov, P. E. 106 Rohr, M. 88 Mao, T.-F. 139 Papaefthimiou, P. 87 Romand, M. 180 Mar, A. 86 Park, J.-B. 137 Roman-Martinez, Marauela, M. D. 42 Niidasdi, L. 44 Park, K. Y. 138 M. C. I35 Marecot, P. 137 Nagata, K. 89 Paul, J. 181 Roodt, A. 140 Marella, M. 84 Naicker, K. P. 88 Paulasaari, J. K. 139 Rothenberg, G. 87 Mark, J. E. 172 Nalbantian, L. 43 Pauls, H. W. 182 Rottman, C. 43 Martin, B. R. 14 Namhoodiri, V. 182 Pearton, S. J. 157 Russell, A. E. 139 Maruko, T. 106 Natan, M. J. 14 Pecchi, G. 43 Rytvin, Ye. I. 32 Massicot, F. 135 Natarajan, K. 140 Perathoner, S. 84 Mathew, R. J. 139 Neumayer, D. A. I07 Petch, M. I. 108 Sacht, C. 140 Matsukata, M. 138 Neurock, M. I35 Peters, A. 73 Saenger, K. L. 107
Phtinwn Metah h.,2000,44, (4) 189 Page Page Page Page Sakamoto, Y. 179 Smith, I. W. S. 56 Van Der Schaaf, Wong, W.-T. 136 Salleo, A. 89 Souleimanova, P. A. 182 Wright, J. 156 Salomon, E. 156 R. S. 137 van Koten, G. 41 wu, c. 32 Samman, A. 137 Spek, A. L. 41 van Loyen, D. 136 Wu, J. 32 Sands, T. 89 Stanczyk, T. 180 Vankelecom, I. 88 Wyatt, M. 31 Sano, M. 86 Steenwinkel, P 41 Varma, A. 137 Sartorel, A. 182 Steiner, A. 136 Varma, R. S. 88 Sasson, Y. 43.87 Stott, F. H. 40 Vasanelli, L. 87 Xiao, J. 136 Sayan, S. 181 Strukul, G. 84 Vasekin, V. 32 Xomeritakis, G. 43 Scarafoni, A. 179 Sulman, E. 88 Verykios, X. E. 87 XU, G.-Q. 42 Scarcia, V. 40 Sun, S. 135 Vespui, G. I39 xu, L. 136 Scelza, 0. A. 181 Sunley, G. J. 89 Vizza, F. 44 Schanssema, F. 139 Sutapun, B. 40 Vogler, A. 41, 136 Schildenberger, M. 138 Suzuki, K. 181 Volkert, E. W. 50 Yakushi, K. 135 Schindler, K.-P. 73 Svensson, M. 85 Volpe, C. 106, 156 Yam, V. W.-W. 40 Schlogl, R. 167 Vorlop, K.-D. 84 Yamabe-Mitarai, Schmal, M. 138 Y. 107 Tabib-Azar, M. 40 Schmid, L. 88 Yamaguchi, I. 139 Taher, H. A. 86 Schmitt, D. 85 Wakeshima, M. 40 Yamamoto, K. 181 Takada, A. 89 Schouwstra, R. P. 33 Wallace, J. 71 Yamamoto, T. Takaya, H. 139 88, Schroder, D. 87 Walsh, M. P. 22, 72 139 Takeda, K. 135 89, Schwarz, H. 87 Walter, J. 85 Yang, J.-H. 137 Takenaka, Y. 139 Schwarz, 0. 136 Wambach, J. 87 Yang, Y. 32 Tamada, Y. 44 Scorrano, G. 182 Wang, D. 135 Yanov, I. 88 Tamura, H. 137 Sebastian, P. J. 89 Wang, J. L. S. 42 Yentekakis, I. V. 43 Tanaka, Y. 181 Seehock, R. 180 Wang, L. 182 Yin, M.-Y. 87 Taylor, S. S. 57 Sellin, M. F. 182 Wang, M. 86 Yoon, S.-G. 137 Tekaia-Elhsissen, K. 39 Serban, A. 137 Wang, S. 32 Yu, K.-L. 40 Thangadurai, T. D. 140 Serrasqueiro, Watanahe, M. 88 Yu, w. 179 Thomas, K. R. J. 85
R. M. 180 Watkins, J. J. ~ 180 Yu, W..Y. 181 Thompson, D. T. 31 Setty-Fichman, M. 43 Weber, W. P. 139 Yu, X. H. 107 Thompson, M. E. 66 Sharp-Goldman, Weller, D. 135 Yu, X.-Q. 181 Tillement, 0. 135 s. L. 140 Wengrow, A. B. 89 Yuan, G.-L. 87 Toma, H. E. 180 Shchetkovskiy, A. 106 West, D. R. F. 30 Yumura, T. 181 Tomaselli, M. 84 Sheldon, R. A. 139 Tomita, A. 86 White, K. W. P. 57, Shi, T. 140 84, 107, 155 Tomizawa, H. 136 Shigeoka, T. 85 White, P. 39, 66, 111, Zanardi, F. 179 Torii, K. 140 Shimamune, T. 106 119, 124, 157 Zaworotko, M. J. 41 Tornroos, K. W. 136 Shin, H.-C. 157 Wiener, H. 87 Zee, R. H. 179 Toshima, N. 166 Shirai, M. 135, 138 Williams, J. A. G. 41 Zhang, A. P. 157 Toth, L. F. 106 Shiroishi, H. 44 Wills, A. S. 179 Zhang, F. 89 Toulmin, J. 73 shirotani, I. 135 Wilson, R. G. 157 Zhang, J.-Y. 42 Treadwell, M. 72 Shul, Y. G. 138 Winemiller, M. D. 139 Zhang, Q. 43 Tseung, A. C. C. 42 Sibley, S. 66 Winnischofer, H. 180 Zhang, R. 172 Tsuda, H. 72 Siciliano, P. 87 Winquist, F. 57 Zhang, X. 137 Tsuji, J. 88 Siivola, A. 175 Wiss, F. 179 Zhang, Y. 32 Tung, C.-H. 42 Sionato, J.-P. 182 Witcomh, M. J. 56, 85 Zhao, F. 138 Turro, N. J. 136 Singh, A. K. 136 Wittwer, V. 155 Zhao, H. 32 Tushingham, M. 72 Sitran, S. 40 Wokaun, A. 87 Zhao, S. 42 Twigg, M. V. 67 Slade, E. 15 Wolff, I. M. 57, Zhen, W. 89 Smeaton, W. A. 125, 107, 158 Zhou, M. 40 166 Unsworth, J. 73 Wolfson, A. 88 Zima, J. 87 Smirnov, A. 107 Unwin, P. R. 21 Wong, C.-H. 167 Zimmermann,B. 44 Smith, G. D. W. 40 Uttamlal, M. 42 Wong, W.S. 89 Zocco,A. 87
Plniinrrm Met& b.,2000,44, (4) 190 SUBJECT INDEX TO VOLUME 44
Page Page a = abstract Carbon Oxides, CO, (con?.) Acetates, ethyl, oxidation, n 87 effect on H2 permeation, of membranes, a 85 vinyl, hydroformylation, a 44 hydrogenation, to alcohols 3 Acetic Acid, by carbonylation of MeOH 89.94 living alternating copolymerisation, with allenes, a 139 Cativa” process 94, 146 for NO reduction, on Wsupport, a 138 Acetylenes, hydrogenation, a 138 oxidation, on anodic catalysts, for PEFCs, a 89 Acrylates, methyl, for iodobenzene vinylation, a 138 over PdzsZr7s,a 87 ADMET, in organic synthesis 168 on Pt/C electrocatalysts,u I39 Alcohols, allyl, hydrogenation, a 181 reaction with NO 3 by CO hydogenation 3 relativistic effects on PGMs 146 ethyl, sensor, in beer and wine, a 42 removal from reformate, using Demonox” unit 108 methyl, carbonylation, Irfl catalysed 89.94 sensor, a 137, 180 over Rhhydrotalcite, a 88 in tobacco smoke, oxidation, by PGM catalysts 120 oxidation, a 88 Carbonylation, MeOH 88, 89.94 Alfa Aesar, “High Purity Metals” catalogue 55 Carbonyls, OsCO’, Os(CO),, Os(C0);. IR spectra. a 40 Alkanes, hydrogenolysis 3 PGM clusters 3 Alkenes, epoxidation, a 181 Ru,(CO),z, decomposition, a 87 hydrogenation, a 43 RuCO’, Ru(CO),, Ru(CO);, IR spectra, a 40 Alkoxycarbonylation, 4-bromoacetophenone, a 182 Carboxylic Acids, citrate, effect on PtCId2-reduction, a 179 Alkynes, as ligands, in [Pt2Cu4(C=CPh)&, a 40 Casting, lost wax, for jewellery manufacture 156 Allenes, copolymerisations, a 139 Catalysis, book reviews 15,56, 167 Alloys, dental 31 combinatorial screening techniques 16 eutectic 158 heterogeneous, a 43.87-88, 137-138, 181-182 ferritic 158 time resolved DRIFT studies, a 87 high-temperature 158 homogeneous, a 44, 88-89, 138-139. 182 jewellery 56, 156 in metathesis 58, 112, 168 shaoe memory, a 179 relativistic phenomena, in chemistry of PGMs 146 AUylbenzenes,by Suzuki coupling, a 88 solventless, microwave-assisted, Suzuki coupling, a I82 Aluminium, Al-Ir, Al-Ni-Ru, AI-Ru, phase diagrams 56 in subcritical H20, a I38 Al-Ir-Ru, phase diagram 56,85 Catalysts, Adams, a 43 Ir-IrAI, Ru-RuAl, formation 158 auto-, see Autocatalysts NdRhaAll5 37. synthesis and structure, a 86 book reviews 15.56, 167 Pt-AI-X, for high-temperature use 158 Grubb’s 168, 182 TiAl-Ru, properties of, a 40 model, “nanopits” and “nanotowers”, a 138 Amidation, nitriles, with mines, a 139 PGM/polymer, book review 15 Amination, 2(,5)-(di)bromothiophenes,a 88 PGMs, in HotSpot” reformer I08 Amines, from olefins, by hydroaminomethylation, a 44 to limit tobacco related diseases I20 reaction with Pd and Pt dithiocarbamates,a 40 recovery, a 41, 88, 138, 139 Ammonia, coupling with CIL, HCN synthesis, a 87 recycling, a 43.87, 138, 181, 182 in hydroaminomethylations, a 44 “ship-in-bottle” 3 oxidation, in nitric acid manufacture 74 three-way, see Three-Way Catalysts Antibacterial Agents, Ru(II1) complexes, a 140 Catalysts, Iridium, Ir2Si oxide, Ir3Ti oxide 16 Arenes, vinyl, hydroformylation, a 44 Ir/y-Al~O3,Ir/Si02, Ir/silicalite, NO reduction, a I38 Autocatalysts, conferences 31.67, 71 Catalysts, Iridium Complexes, Cativa” process 94 diesel treatment 67 Ir hydrides, low valent, for nitrile activation, a 139 emission control 22, 31.56 Irfl, in MeOH carbonylation 89.94 lean-NOx 67 [IrCI,( 1,5-~yclooctadiene)],Ic13, [IrCl,(cyclooctene)], selective catalytic reduction 67,71 [IrC13(norbornadiene)],IrCI3.3H20, metathesis 58 Rh/Ir/TPPTS, olefin hydroaminomethylation, a 44 Benzene, ethyl-, dehydrogenation,a 181 Catalysts, Osmium, Os2Si oxide 16 Benzoic Acid, hetroaryl, synthesis, a 182 Catalysts, Osmium Complexes, OsCIj, metathesis 58, 168 BiDbenvl. svnthesis. a 87 OsCldhvdratel OsC1-.3H,O. metathesis 58 B&ndi;g,’p;essure, using Pd-In, a 89 OsH~(~O)(Oz)(PR3)2.OsHC1(CO)(PR3)2, Book Reviews, “Catalysis by Polymer-Immobilized OsHCl(CO)(PPh,)(dppp),hydrogenation, a I39 Metal Complexes” I5 Os(II) naphthalenes, cyclisation reactions, a I39 “Catalysis from A to Z 167 Catalysts, Palladium, PdlSi oxide 16 “Metals and the Royal Society” 30 PdzsZr7s, CO oxidation, a 87 S. Afx J. Sci., Pt in South Africa 56 Pd-Cu/Dowex 50 W X,nitrate removal from H20,a 43 Busbveld Complex, geology, Pt and Pd reserves 33, 56 Pd-CwTi02, Pd-CdZrO,, nitrate reduction 84 Pd-In, Pd-Sn, nitrate reduction 84 Cancer, drugs 31, 56, 140 Pd-Pt-Ce/A1203,bleach plant effluent treatment, a 43 Capacitors, in electronic equipment 107, 137, 140 Pd-SnlTi02, Pd-SniZrO,, nitrate reduction 84 Carhenes, Pd, fluoroalkylatedN-heterocyclic, a 136 Pdy-ALO,, CFZCl2hydrogenolysis, a 138 Ru, in metathesis 58, 112, 168 PdIAhO3, propane oxidation, a 138 Carbocycles, synthesis 112, 138 Pd/y-AIzO,, trichloroethylene oxidation, a 138 Carbon, nanotubes, electrooless plating of metals onto, a 42 PdC, acetylenes hydrogenation, a 138 origins and pretreatment of, for PEVC catalysts, a 181 iodobenzene vinylation, a I38 WC fibres, HZadsorption, a 135 olefins hydrogenation, a 138 Carbon Oxides, C02,compressed, solvent, a 44 origin of C, pretreatment of C surface, a 181 sc-, solvent, a 136, 180, 182 Pd/C and PEG-400, aryl-aryl coupling, a 87 CO, codeposition with 0s and Ru, a 40 Pd/KF/AIz03,Suzuki coupling, a 182 copolymerisation,with ethene, a 44,139 Pd/“Mg-smectite”, iodobenzene vinylation, a 138
PLdnnm Metah Rav., 2000,44,(4), 191-1 96 191 Pqe Page
Catalysts, Palladium, (cot7t.) Catalysts, Ruthenium Complexes, (corn.) Pd/SiO1, iodobenzene vinylation, a 138 RuClr(=CHCH=CPh:)(PR,),. ROMP 168 Pd/SiO?, “nanopits”. “nanotowers”. (I I38 RuCI,(=CHPh)(PCya)?.metathesis 112. 168 Pd/zeolite-X, methyldecalin hydrocracking. (I 181 RuCI?[PhrP(CH1),PPh,]JSiOa.for N,N-diethyl- PdCldclay, Suzuki coupling, a 88 formamide synthesis, (I 88 Catalysts, Palladium Complexes, a-allylpalladium. a 88 RuCII(PPhJ)2(=CHPh).metathesis 58 ($-Cm)Pd(PPh3)?. theoretical studies, a 88 RuCIr(PPhi)i, ROMP 168 Pd carbenes, a 136 RuCI,(PRI)?(=CHC~HKH=)RUCI~(PRI)?,ROMP 58. 168 Pd + 1 .3-CIHo[P(ChH,-2-OMe-5-S0,Na)?l?,a 139 RuCI?(PR&(=CHCH=CHPh).metathesis 58 Pd-wool, carbonyl hydrogenation, a 87 [RuCIj(COD)]. ROMP 168 PdCldAdogen 464, oxidation of alcohols, a 88 RuCI,. RuCl,(hydrate), [RuCI i(norbomadiene)J, PdClJpolystyrene. preparation. (I 86 [RuCll(norbornene)]. Ru(HIO PdCIdPhCN)?/PPh,. in alkoxycarbonylation. (I I82 [RuH], RCM. metallacycle synthe Pd(OAc)?, carbocycle synthesis, a I38 RuHCI(CO)(PPhl)3,ADMET reac ions Pd(OAc)dPBu’3, dibromothiophenes + diarylamines, a 88 Ru(I1) porphyrin-resin, alkene epoxidation, a 181 Pd(OAc)2P(o-tolyl),, Suzuki coupling, a I82 CativaTht,acetic acid manufacturing process 94, 146 [Pd(P-P)(N-N),J(PFh)2,CO + C>H4copolymerisation, a 44 Chemiluminescence, see Luminescence Pd(PPh,)CI2, Suzuki coupling, a I82 Chlorobenzenes, in aryl-aryl coupling. 87 Pd(PPh&. in alkoxycarbonylation, a I82 Chlorofluorocarbons, CF2C12.hydrogenolysis, a 138 coupling reactions, a 89 CHP Systems, using HotSpotT” fuel reformer 108 Suzuki coupling. a I82 Clusters, alloy, in MCM-4 I, in NaY 3 (R,N):PdX, oxidation of alcohols, a 88 Chini. synthesis 3 Catalysts, Platinum, R’, HCN synthesis, (I 87 PGM carbonyls, in FSM-16. in NaY 3 [PtdCOhI’I, IPtldCO)2aI’-DJaY,[Ptl~(CO)alllr~[NBu?l+/, IRh6(CO)l~(COOMe)l-.IRu!,C(CO)I,,(COOMe)J-, a 179 [Ptl3(C0),(,]’ [NEtJ+/FSM-I6, Pt nanoparticles/, transformations to nanoparticles. in microlmesopores 3 Pt nanowires/FSM-16, WGSR 3 see also Nanoclusters Pt, sputtered on gasochromic sol-gel WO1 films I55 Coatings, Ir oxide, for electrodes 106 Pt-Co/, Pt-Cu/. Pt-Fel, Pt-Ni/, Pt-RulC. for medical implants 106 Pr/C/Nafion, for DMFC, (I I82 multilayer. MoRu/Bc. II 140 Pt/, Pt-Gd, Pt-Pb/. Pt-Snl. Pt-Sn-Ga/AI2O3. Al>Oi+ K. see also Deposition and Electrodeposition ZnAl,O,, propane dehydrogenation, a 181 Colloids, Au-Pt, Pt-Au, a 136 Pt-Rh/Al~O3-CeO2.TWC, a I37 AuPt, Au/Pt/Au 14 Pt/y-AlrOi, Na-promoted, NO reduction by propene, a 43 Pd. aggregation behaviour, using cryo-imaging 111 Pt/y-A1203,trichloroethylene oxidation. a I38 Pd-Cu. a I35 Pt/C electrocatalysts, CO oxidation, a 139 Pt, on poly(N-isopropylacry1amide)-SiOz,a 181 Pt/Cello& ~02,TWC. oxygen storage capacity I24 Combinatorial Chemistry, in heterogeneous catalysis I6 Pt/poly(N-isopropylacrylamide)-SiO2, hydrogenation, n 1 8 I Conferences, 14th Santa Fe Symposium, Albuquerque, Pt/W’+-doped TiO!, ethyl acetate oxidation. u 87 New Mexico. U.S.A.. May. Zoo0 156 PtClr with Dowex’ 1, alkene hydrogenation. (I 43 First Int. Symp. on Iridium, Nashville. Tennesse. PtOJA1,O1, PtRuO,. colloidal (pre)catalysts, (i 43 U.S.A.. March. 2000 106 Catalysts, Rhodium, Pt-Rh/AI?OXeO2,TWC, a 137 Int. Symp. on Precious Metals, Kunming, RhlTi oxide, Rh2Si oxide. Rh2Ti oxide 16 China, Sept., 1999 31 Rh nanoparticlesihydrotalcite, MeOH carbonylation, a 88 SAE, Detroit. U.S.A.. March, 2000 67 Rh/ZrOr-Si02. CH, combustion, a 43 Second Int. Conf. on Health Effects from Vehicle Catalysts, Rhodium Complexes, chlorotris- Emissions. London. U.K.. Feb.. 2000 71 (triazaphosphaadamantane)Rh(l),hydrogenation, a 44 Copper, CuAIPd, shape memory properties. II 179 (R)-BINAP-Rh(1). vinyl acetate hydroformylation. (I 44 elcctrolcss deposition, (I 42. 180 Rh2(OAc)4,in cyclopropanations. a I39 Coupling Reactions, biphenyl synthesis. (I 87 Rh phosphites, hex- 1-ene hydroformylation. a I82 bis(diary1amino)thiophenes synthesis. (I 88 Rh (R,S)-H’F-BINAPHOS, in hydroformylations, u 44 C-N, for HCN synthesis, CI 87 Rh-MeDuPHOSPDMS, hydrogenation, a 88 poly(aryleneethyny1ene) synthesis. (I 89 Rh/Ir/TPPTS, olefin hydroaminomethylation. a 44 see also Heck Reactions and Suzuki Couplings RhCh, metathesis 58 CRTT”, for diesel emission control 67.71 (RhCI(COD)I], vitamin E synthesis, N 182 Crucibles, Ir. for crystal growth 106 Rh(q’-CH(Ar’)C( C(=CHAr’)CHIC(=CHAr’)- Crystals, RRh1Ge2(R = Gd. Tb. Dy). magnetism. (1 85 CHCH2CH=CHAr’]CH?](PPh,)2.II I39 Cycloolefins, ROMP 58. 168 Rh(PPh3)2LCI(L = CO, PPh3). metathesis 58 Cyclopropanation, styrene with diazoindanone, a 139 Wilkinson’s catalyst, dehydrocoupling polymerisations 172 Catalysts, Ruthenium, Mo,Ru,Se-(CO),,. for PEFC. a 89 Dearomatisation, naphthalenes, N 139 PtRuO,, colloidal (pre)catalysts. a 43 Decarbonylation, of Ru nitrosonaphthols. a 136 [PWI~O,~RU”(DMSO)]~~,in oxidations. a 182 Decarboxylation, of ally1 carbonates, ally1 formates. RulTi oxide, Ru?Si oxide, Ru3Ti oxide 16 ally1 P-keto carboxylates, 17 88 Ru/anion exchange resin, in H2 generation, a 140 Dehydrogenation, hydrocarbons. (I 181 RulSi02 aerogel. for N.N-diethylformamide synthesis. a 88 Demonoxmt, CO clean-up unit. for HotSpotT” reformer 108 Catalysts, Ruthenium Complexes, dihydridocarbonyl- Dental, alloys, Pd-Ag. Pd-Au 31 Ru(PPh,),, poly(silyl ethers) synthesis, a 139 Deposition, chemical tluid, of Pd, Pt, Rh, (I 1x0 Grubb’s catalyst 168, 182 pulsed laser. of Ir thin films. (I 42 K2RuC15,metathesis 58 of SrBirTa20qthin films. a 89 poly-cis-[Ru(~hpy)~(py)~](PF~)?.in electrocatalysis. a 136 see also Coatings and Electrodeposition Ru carbenes, metathesis 58, 112, 168 Dienes, addition of phenols. (I I82 Ru hydrides, low valent, for nitrile activation, a 139 Diesel, emission control 22.67 Ru-melanoidin. for H, generation. from HzO. a I37 particulates, control by CRT’” 67,71 Ru(bpy),” + Ru02 a&&bing Ru-red, H20oxidation, u 44 PDiketones, Ir(1II) P-diketonates 106, 179 RUCM=CHI)(PCY~)~,RCM I12 Ru(l1l) P-diketones, butddiyne bridged polymer, u 41 RuCId=CHCH=CPh2)(PCyi)2, RCM 112 DNA, cleavage, a 179
Phtimm Me& h.,2000,44, (4) 192 Page Puge
Effluents, bleach plant, treatment with Pd-Pt-Ce/AI2O3, a 43 Fuel Cells, (cont.) Electrical Contacts, Pd-Ge ohmic contact, to GaAs, a 44 DemonoxTMCO clean-up unit 108 Electrocatalysis, poly-cis-[ R~(vbpy)~(py),](PF&,a I36 DMFC, Pt-Co/, F‘t-Cu/, Pt-Fel. Pt-Nil, Pt-Ru/C, Electrochemistry, a 41.86 PtlCINafion, electrocatalysts, a I82 Ir oxide films, redox reactions, a 86 Hlgenerator, for PEMFC, a 140 Ir(lV) chloro complexes, for insulin determination, a 181 HotSpotTMreformer I08 PUTi electrodes, voltammetric behaviour, a 86 PEFC, CO oxidation, activity of anodic catalysts, a 89 Ru binuclear pyrazines, molecular hysteresis, a 86 Mo,Ru,Se;(CO),, electrocatalysts for, a 89 Electrodeposition, of Au/Pt and AWAucolloids 14 WC, Ru/C, Pt-RulC, anodic catalysts, a 89 Ni/Pd, on Cu, a 86 PEMFC, HZgenerator for, a I40 Pd, for decorative and functional applications 156 Pt I BAMa 407. a 44 platinised Ti, for electrodes, a 86 Pt I Nation, a 89 Pt, for decorative and functional applications 156 Pt I Nafiona 117. a 44 from alkaline electrolyte, a 180 Pt/C electrocatalysts, EXAFS of CO oxidation, a 139 Pt black, on evaporated Pt electrodes, a 180 PtRuO, colloidal electrocatalysts, a 43 Pt films, onto microelectrodes, a 86 SPFC I08 Pt and W, onto Au, a 42 Fullerenes, ($-CN,)Pd(PPh&, catalytic mechanism, a 88 Rh, for decorative and functional applications 156 Sn, using Ir0,-TalOs-SnO2i electrodes, a I37 Gasochromism, in sol-gel Pt (sputtered) W03films 155 see also Coatings and Deposition Gauzes, Pt-Pd-Rh, Pt-Rh, metal surface composition 74 Electrodeposition and Surface Coatings, a Geology, South Africa 33.56, 105 42.86-87, 137, 180 Germanium, RuZGe,, optical spectra, a I35 Electrodes, gate, Pt-SnOl. porous, in CO sensor, a 180 Graphite, layers, for forming Pt nanosheets, a 135 Ir oxide coatings 106 Ir-Ta-0, for SrBi2Ta10pthin film deposition, a 89 Heck Reactions, iodobenzene with methyl acrylate, a 138 Ir-Ta-OiTdSi, properties, a 89 Pd catalysts, without ligands, a I38 Ir02-Ta20s-Sn02/Ti, for Sn plating, a 137 Helium, permeability, in Pd-YSZ membranes, a I80 IrOJglassy C, in insulin sensor, a 181 Heterocycles, in synthesis 112. 168 microjet 21 Hex-1-ene, hydroformylation, a 182 0s-gel-HRP/XOD/glassy C, biosensor, a 181 “High Purity Metals”, Alfa Aesar catalogue 55 PdO, as damage markers, in RAM capacitors 107 High Temperature, alloys 158 Pt, micro-, with high surface areas, a 86 History, discovery of the Pt isotopes I73 tubular, as amperometric detector, a 87 Etienne Lenoir 125, 166 Pt+C+PTFE/C cloth, for Ni electrowinning, a 41 “Metals and the Royal Society”, George Matthey, Pt black on evaporated Pt, preparation, a I80 Percival Norton Johnson 30 Pt I WOI, EtOH sensor, a 42 metric s stem, kilogramme, metre 125, 166 PtlRdpoly-Si, by MOCVD, integration, a 137 HotSpotTs Reformer, fuel processor 108 mi,voltammetric behaviour, a 86 Hydration, nitriles, a I39 radial flow microring 21 Hydroaminomethylation, olefins, a 44 Ru intermetallic compounds, for spark plugs 56 Hydrocarbons, dehydrogenation. a 181 Ru-Rh + poly( 1,3-diaminobenzene), H202detection, a 42 methyldecalin, hydrocracking, a 181 ultramicro-, Pt disc, Pt ring 21 traps, in emissions control 67 Electroless Plating, Cu, a 42, 180 Hydrocracking, methyldecalin, a 181 Pd, onto C nanotubes, using Pd-Sn activator, a 42 Hydrofonnylation, vinyl acetate, vinyl arenes, a 44 on porous Vycor glass, for membranes, a 137 hex- 1-ene, in sc-COl, a 182 thin films, on composite membrane, a 43 Hydrogen, adsorption, on WC fibres, a 135 Pd activator, using dielectric banier discharge, a 180 chemisorption, on Pd-Re, a I35 Pt activator, from Pt acetylacetonate films, a 42 effects, in Pd films, a 40 Electronic Nose, gas emissions, detector 57 isotherms of internal oxidation, in P&.wRhoosNie,s.a 135 Electrowinning, Ni, using Pt+C+PTFE/C cloth anode, a 41 permeation, in Pd membranes, a 43,85 Emission Control, motor vehicles 22, 3 I, 56, 67, 7 I, 124, 137 photoevolution, via Pt-loaded LB films, a 41 Epoxidation, alkenes, a 181 production, by HotSpotTMfuel processor 108 Esterification, nitriles, with alcohols, a 139 using Ru catalysts, a 137, 140 Ethene, with CO, copolymerisation, a 44, 139 reduction. of PtC14’-, a I79 relativistic effects on PGMs 146 sensor, a 40 Ethers, crown, synthesis 112 separation, by Pd/a-Al2O3 membranes, a 43 Ethyl Acetate, oxidation, over Pt/Wh’-doped Ti02,a 87 sdlubility, inPdAg, PdRh, a I79 Extraction, PGMs 31.33, 56, 105 Hydrogen Cyanide, from CH4 + NHI, Pt’ mediated, a 87 Hydrogen Peroxide, detection, a 42 Films, by chemical fluid deposition, Pd, Pt, Rh, 180 acetvlenes. 138 a Hvdromnation.“- ~ a gasochromic, sol-gel Pt (sputtered) WOI 155 acrylonitrile-butadiene copolymers, a 139 Ir oxide, redox reactions, a 86 alkenes, a 43 Ir-Ta-0, by reactive sputtering, a 89 ally1 alcohol, a 181 Langmuir-Blodgett, Pt loaded, porphyrins, a 41 asymmetric, 3-methyl-2-butanone. diacetone alcohol, a 87 NiPd, on Cu, reaction with Sn-Pb, a 86 by PGM/polymer catalysts 15 Pd, stress and resistivity changes, with H?, a 40 co__ 3 Pt, nanostructured, for microelectrodes, a 86 1-decene, a 43 Pt acetylacetonate. ohoto-induced decomoosition. a 42 methylacetoacetatc, a 88 PZT, a- 140 olefins, a 138 see also Thin Films phospholipid liposomes, a 44 Formamides, N,N-diethyl-, synthesis, a 88 Hydrogenolysis, alkanes 3 Fuel Cells, a 44.89, 139--140, 182 CFdX, a I38 AFC, Pd-based H2 diffusion electrodes, a 140 propane, a 138 WC-PTFE electrodes. a 140 Hydrosilylation, in polymerisations, a 139 anode exhaust gas burner. for HotSpot“ system 108 Hypoxanthine, biosensor, a 181
PLdimm Met& Rev., 2000,44, (4) 193 PUg' Page Insulin, sensor, a in1 Merensky Reef, geology 33,56 Intermetallics, PGM-based, high-temperature use 158 Metallisation, Pd. Pt. Rh, chemical fluid deposition. a 180 todobenzene, vinylation, a 138 Metathesis, acyclic diene I 68 Indium, coatings, for rocket thrusters I06 ring-closing 112 crucibles, crystal growth 106 ring-opening polymerisation 58. 168 in jewellery I06 Methane, combustion. on RhlZrO2-SiO2,u 43 in MOSFETs 57 coupling with NH,, HCN synthesis. (I 87 refining 106 formation, during MeOH carbonylation. a 89 spark plugs I06 sensor, by Sn02/Os thin films, a n7 thermocouples 106 Metric System, history 125, 166 thin films, by pulse laser deposition, a 42 Michael Additions, in Os(I1) complexes. a 139 Iridium Alloys, Al-lr, phase diagram 56 Microwaves, for Suzuki couplings. a I82 Al-Ir-Ru, phase diagram 56.8.5 for synthesis. of [PW,101,Ru"(DMSO)15. a I82 for high-temperature use 158 Mining, South Africa 33.56, 105 lr-IrAI, eutectic, formation 158 MISFETs, sensor, for CO detection. a 180 (Ir,Ru)Al 106 MOCVD, Pt/Ru, electrode structures. on poly-Si. a 137 Iridium Complexes, (q-CsHs)lr(C0)2,as a ligand, a 41 MOSFETs, in electronic nose 57 lr P-diketonates 106, 179 lr fluoro derivatives 106 Nanoclusters, PGM, synthesis 3. 166 Ir(ll1) bis-terpyridines, pH sensitive luminescence, a 4 I Nanoparticles, Auco,ePt
Langmuir-BlodgettFilms, H. evolution, a 41 Ohmic Contacts, see Electrical Contacts Lasers, KrF excimer. deposition of Ir thin films, a 42 Oletins, cyclo-. ROMP 58, 168 LEDs, organic, from Pt porphyrins 66 hydroaminomethylation. (I 44 Luminescence, chemi-, Rh(bpy),'+, dodemorph sensor, (I I37 hydrogenation. a 138 lr(lI1) bis-terpyridines, as pH sensors, a 41 Optical Properties, Ru2Gei, Ru'Si,. a 135 Nafion membranes, dyed with Ru(I1) complexes. a 42 Osmium, powders. high purity. synthesis 31 photo-, Pd3(acetate)h,a 41 with Sn02,sensor, for CHI. a 87 [Rh"'(phpy)dCN)$. u 136 Osmium Complexes, Cp(OC)~IrOs(CO)l(GeC1l)(CI), [Pt,Cu4(C=CPh)x12,a 40 cp(oc)'lros(co)i(x)~,a 41 [Ru(bipy),(Sbipy)]'+, a I80 electrodes. 0s-gel-HRP/XOD/glassy C, biosensor, a 181 OsCO'. Os(CO),. Os(CO), , IR spectra. (I 40 Magnetism, ferro-, in FePt nanocrystal superlattices, a 135 Osmosis, in Pd membrane preparation. a 43, 137 in Pr,RuO,, a 179 Oxidation, adamantane. a 182 in RPdA (R = Ce, Gd), a 40 alcohols, o 88 in RRh2Ge2 (R = Gd, Tb, Dy), n 85 bleach plant effluents, over Pd-Pt-Ce/Al1O3. a 43 Medical, implants. Ir oxide coatings I06 co, n 87, 139 Ru complexes, antibacterial agents, a I40 in tobacco smoke. by PGM catalysts I20 Membranes, Pd composite, for H2 separation, a 181 cyclooctene, a I 82 Pd-Ag/y-ALO,, preparation, a 43 ethyl acetate. a 87 Pd-modified YSZ, He permeation, a 180 H20,a 44 Pd/a-AI20,, for H, separation, a 43 high temperature. in Ni-Cr-Al-Y-CrC. alloys. a 40 Pdporous Vycor glass, preparation, a I37 internal, in Pd,,,,Rh,,,,,Ni,,,,5.(I 135 Pdstainless steel, H2 permeation, a 85 propane. a 137. 138 PDMS, with Rh-MeDuPHOS, u 88 propene. a I37 Memory, capacitors, Pt/BST/Pt, /Pt/Ru, RuOl, a 140 toluene 16 ferroelectric, PZT/Pt/TiN/Si and Si02multilayers, a 140 trichloroethylene, a 138 RAM, with PdO bottom electrode, as damage marker 107 vocs, a 87,138
Phinnm Metalr Rm, 2000,44, (4) 194 Page Page Oxygen, sensors, a 42 Platinum, (cont.) Ozone, motor vehicle pollution 22 nanosheets, between graphite layers, a 135 powders, submicron 39 Palladium, activator, for electroless Cu plating, a 180 Pt, to Ni-Cr-Al-Y-CrlC2, effects on oxidation, a 40 colloids, aggregation behaviour, cryo-imaging of 11 I Pt/C fibres, H2 adsorption, a I35 Cu/Ni/Pd, interfacial reaction with Sn-Pb, a 86 mu,electrode structures, on poly-Si, by MOCVD, a 137 HI effects on, a 40 PZTPVTiNISi and SO2multilayers, a I40 membranes, a 43,85, 137, 180, 181 Schottky diodes, AWGaN, properties I57 in MOSFETs 57 thermal decomposition of NaCl on, a 85 nanoclusters, Au/Pd, PdAu, Pd/Au/Ag 166 thermocouples, thermoelectric behaviour, a 137 nanoparticles, 2D, a 85 Platinum Alloys, CoPt ultrathin films, by sputtering, a 40 with Pd-In, pressure bonding, a 89 Feh, nanocrystal superlattices, nanoparticles, a 135 powders, submicron 39 ultrathin films, by sputtering, a 40 thermocouples, thermoelectric behaviour, a 137 for high-temperature use 158 Palladium Alloys, CuAIPd, shape memory properties, a 179 jewellery 56, 156 membranes, a 43 Nd,Cel,PtlSb,, Kondo insulator, pressure tuning 55 nanoparticles, PdxCu,m,, a 135 Pt-AI-X, for high-temperature use 158 PdosoRhoosNio~s,internal oxidation, a 135 Platinum Complexes, cancer drugs 31.56, 140 Pd-Ag and Pd-Au, dental 31 organo-Pt(IV) polymers, by H-bonding I I8 Pd-Ge ohmic contact, to GaAs, a 44 poly-Pt porphyrins, O2 sensors, a 42 Pd-In, for pressure bonding, a 89 [Pt2Cu4(C=CPh)s]a,luminescence, a 40 Pd-Re overlayers and surfaces, H2 chemisorption, a 135 [Pt,(l,-Te),(dppe),lCl,,synthesis, a 179 PdAg, PdRh, H solubility, a 179 Pt acetylacetonate, photo-induced decomposition, a 42 Palladium Complexes, [Pd2(l-Se)2(dppe)2],synthesis, a 179 Pt dithiocarbamates, reactions with amines, a 40 Pd,(a~etate)~,photoluminescence, a 41 Pt porphyrins, in organic LEDs 66 IPdl(ll-Se)2(dppe)lIC12, synthesis, a 179 rrans-[PtCI,( 1,4-oxatellurane)2], synthesis, a 136 Pd acetate, plasma-mduced chemical reduction, a 180 PtC1:-, reduction by HI. a 179 Pd carbenes, fluoroalkylated N-heterocyclic, a 136 Pt(dmg),, ID, pressure-induced IMI transitions, a 135 Pd dithiocarbamates, reactions with amines, a 40 Pt(I1) end-capped ferrocenes with thiopbene spacers, a 85 Pd olefins, with P ligands, properties, a 85 Pt(I1) heterobimetallics, a 85 trans-[PdClz( 1,4-0xateIlurane)~], synthesis, a 136 [PtMe~(bu,bipy)]+ RCH2X. in Pt(1V) polymers 118 PdCMpolystyrene, a 86 [PtSe4(dppe)],synthesis, a 179 Pd(I1) end-capped ferrocenes with thiophene spacers, a 85 Pt(trpy)CI+ with pyrene substituent, photoproperties, a 180 Pd(I1) heterobimetallics, a 85 Platinum Compounds, BaCuPt2O9, superconductors, a 89 Pd(II) hexametallic cartwheel molecules, a 41 Pt-oxide thin films, by reactive sputtering, a 42 Pd(I1) porphyrins, synthesis of, as DNA cleavers, a 179 PtCh-graphite, by intercalation reaction, a I35 Pd(II) With c6[3,5-(cH2Y)2cd-h]6, a 41 Zeise's salt, relativistic effects 146 (R"PdX4, (n-Bu$JhPd2Cb, a 88 Platinum Group Metals, in HotSpotlM system 108 Palladium Compounds, PdCl,-graphite, intercalation, a 85 in limitation of tobacco related diseases 120 PdO, damage markers, in RAMS 107 intermetallics, for high-temperature use 158 RPd3S4(R = Ce, Gd), a 40 relativistic phenomena 146 ZrPd3Sil, synthesis and properties, a 86 Platreef, geological review 33 Patents 4548,9&92, 141-144, 183-186 Pollution Control, bleach plant effluent, a 43 pH, sensor system, a 41 motor vehicles 22, 31, 56, 67, 71, 124, 137 Phase Diagrams, Al-Ir, Al-Ni-Ru, Al-Ru 56 nitrate removal, from water 43, 84 Al-Ir-Ru 56,85 Polyketones, synthesis, a 139 Phenols, addition, to dienes, a 182 Polymerisation,co-, a 44, 139 Photocatalysis, Ru-melanoidin, for H2, from H20ra 137 dehydrocoupling, to silphenylenesiloxanes 172 Photoconversion, a 4142, 136-137, 180 electro-, of PI porphyrins, a 42 Photoluminescence, see Luminescence hydrosilylation, to poly(silyl ethers), a 139 Photoproperties, nanoparticles, Ab&'tsheii,PLrrAU+eii. a 136 ROMP 58, 168 NO-Ru complexes, with en and ox ion ligands, a 136 Polymers, binding Pt complexes to, for cancer drugs 56 Pd(I1) porphyrins, as DNA cleavers, a 179 nitrile-butadiene, hydrogenation, u I39 Pt(trpy)CI' with pyrene substituent, ILCT character, a 180 metallisation of, a 180 IRu(bipy)2(Sbipy)lZ', a 180 organo-Pt(1V). by H-bonding 1 I8 Ru(I1) polypyndyls, photosensitisers for Ti02,a 136 poly( 1.3-diaminobenzene) + Ru-Rh electrode, a 42 sol-gel Pt (sputtered) WO, films, gasochromism 155 poly(aryleneethynylene),preparation, a 89 Photoreactions, H2 evolution, using Pt LB films, a 41 polycyclic, synthesis 112 [Ru(bipy),(Sbipy)]", + dissolved 02,a I80 poly(N-isopropylacrylamide)-Si02, Pt colloids on, a 18 I "Platinum 2000" 119 poly(N-vinyl-2-pyrrolidone),in core/shell nanoclusters 166 Platinum, capacitors, F't/BST/Pt, mu,/Ru02, a 140 poly(si1yl ethers), synthesis, a I39 colloids, on poly(N-isopropylacrylamide)-Si02, a 181 polystyrene, PdCI, anchorage, a 86 electrodeposition, from alkaline electrolyte, a 180 Ru(II1) P-diketone with butadiyne, a 41 Pt films, on microelectrodes, a 86 silphenylenesiloxanes, synthesis 172 electrodes, see Electrodes for supported PGM catalysts 15 gates, in Sic MOS capacitors, for gas sensors, a 137 unsaturated, from ROMP of cycloolefins 58 isotopes, history of the discovery 173 Powder Metallurgy, in jewellery manufacture 156 jewellery 56, 156 Powders, 0s. Rh, synthesis 31 kilogramme, metre, definitive standards for the submicron, Pd and Pt, synthesis 39 metric system 125, 166 Pressure 'hning, Nd,Celdt,Sb4 55 mining, in South Africa 33, 56, 105 Pt(dmg)2, lD, IMI transitions, a 135 in MOSFETs 57 Propane, dehydrogenation, a 181 nanoclusters, Am,Pt/Ru 166 oxidation, a 137, 138 nanoparticles, A&,Ph, h,Au,k~, preparation, a 136 Propene, from propane, a 181 Pt, from PtCL2-, a 179 oxidation, a 137
Phinnm Metalr Rm, 2000,44, (4) 195 Page Page
Propylene, from propane. a 181 Sensors, (cont.) CO, a 137. 180 Radioactivity, of Rh isotopes. drug production 50 electronic nose, for VOCs 57 Radionuclides, '"'Rh, ""Ru 50 EtOH, a 42 Radiotherapy, isotopically enriched Ir I06 H2 in Pd, using evanescent microwave probes, a 40 iosfi 50 H202. a 42 Rare Earths, RRh2Ge2 (R = Gd, Tb, Dy), magnetism, a 85 insulin, a 181 RCM, in organic synthesis 112 liquid chromatography. (I 87 Reactive Hot Isostatic Pressing, RuAl materials 158 02,a 42 Reduction, NO, a 138 pH. a 41 of Pd/C catalysts, by H?, a 181 propane, propylene, a 137 in subcritical HzO, a 138 vocs 57 Refining, PGMs 31, 106 Shape Memory Alloys, CuAIPd, a 179 Relativistic Effects, on chemistry of PGMs 146 Shape Memory Effect, NbsuRuso,a 85 Rhenium, Pd-Re, Hr chemisorption, a I35 "Ship-in-Bottle" Catalysts, technology 3 Rhodium, '"'Rh, production 50 Silicon, PZT/PfliN/Si+SiO,, ferroelectric memories, a 140 nanoclusters, AdRh 166 Ru&, optical spectra, a I35 nanoparticles, on hydrotalcite, synthesis, a 88 ZrPdjSil, synthesis and properties, a 86 powders, synthesis 31 Silver, PdAg. H solubility, o 179 Ru-Rh electrode, + poly( I ,3-diaminobenzene), a 42 'Smart' Windows, gasochromic 155 Rhodium Alloys, PdowRhoosNiouhinternal oxidation, a 135 Sodium Chloride, decomposition on hot Pt, a 85 PdRh, H solubility, a 179 Solar Cells, Graetzel-type, a 136 Rhodium Complexes, [acac(Rh)(COD)],precursor, a 180 Solder, Sn-Pb, reaction with NiPd, on Cu, a 86 [Rhb(CO)dCOOMe)l-. mass spectrum, a 179 South Africa, Pt mining 33,56, 105 [Rh"'(phpy)r(CN)zl~,photoluminescence, a 136 Spark Plugs, electrodes 56, 106 Rh(PPh3)CI 146, 172 Sputtering, Copt, FePt, thin films, a 40 Rhodium Compounds, NdRhaAl15,,, synthesis, a 86 magnetron, Ir oxide, for medical implants 106 RRhLie2 (R = Gd, Tb, Dy), magnetism, a 85 of MoRu/Be multilayer coatings, a 140 Rockets, thrusters, Lr coatings 106 Pd-Ag submicron films, a 43 ROMP, in organic synthesis 58, 168 plasma, of Pt, onto Nafion, a 89 Ruthenium, additions, to Fe-Cr-Al 158 reactive, of Ir-Ta-0 films, for electrodes, a 89 C-Ru xerogel composites, as supercapacitors, a 41 of Pt-oxide thin films, a 42 MoRu/Be multilayer coatings, a 140 Styrene, 2-diazo- 1 Adanone cyclopropanations, a 139 particles, from decomposition of RU~(CO)~~.a 87 by dehydrogenation of ethylbenzene, a 181 Pt/BST/F't/Ru capacitors, a 140 Superalloys, 'refractory', PGM-based 158 mu,electrode structures, on poly-Si, by MOCVD, a 137 Supercapacitors, C-Ru xerogel composites, a 41 '"'Ru, for production of '"'Rh 50 Superconductivity, B&CuPt209+ F-doped YBCO, a 89 Ru-Rh electrode, + poly( 1.3-diaminobenzene). a 42 Superlattices, FeR nanocrystal, a 135 Ruthenium Alloys, Al-lr-Ru, phase diagram 56,85 Suzuki Couplings, in organic synthesis, a 88, 182 AI-Ni-Ru, Al-Ru, phase diagrams 56 corrosion-resistant 56 Tantalum, TasuRuro.a 85 Fe-Ru, damping capacity 157 Thermocouples, Ir I06 for high-temperature use 158 Pd. Pt, thermoelectric behaviour, a 137 intermetallic, for spark plug electrodes 56 Thin Films, Copt, FePt. by sputtering, a 40 (Ir,Ru)Al I06 Ir, by pulsed laser deposition, a 42 NbsRu50, shape memory effect, a 85 Pd-Ag, on y-Ak03. a 43 Pt-Ru, for jewellery 156 Pd/a-A1201, by electroless plating and osmosis, a 43 Ru-RuAl, eutectic, formation 158 poly-cis-[Ru(vbpy)~(OH~)~l(CIO,),,formation, a 136 Ta&um, o 85 poly-cis-IR~(vbpy)~(py)~l(PF~)~,electrocatalysis, a 136 TiAl-Ru, properties, a 40 Pt-oxide, by reactive sputtering, XPS study of, a 42 Ruthenium Complexes, Cp(OC)21rRu(CO)1(SiCI,),,a 4 1 Ru02,from Rus(C0)1?,a 87 NO-Ru complexes, with en and ox ion ligands, a 136 SrBi2Ta20r.a 89 poly-cis- Ru(vbpy)z(py)~](PF~)~.electrocatalysis, a 136 see also Films and Membranes Rh(bpy), \+ , chemilummescence, dodemorph sensor, a 137 Three-Way Catalysts 31. 124, 137 [RUC(C~)I~(COOM~)]-,mass spectrum, a 179 Tin, plating, using IrO2-Ta205-SnO2Rianode, a 137 Ru binuclear pyrazines, molecular hysteresis, u 86 Titanium, TiAl-Ru, properties, a 40 Ru nitrosonaphthols, synthesis, a 136 Tobacco, smoke, oxidation, by PGM catalysts 120 Ru-melanoidin, photocatalyst, HzO to HZ,a 137 Trichloroethylene, oxidation, a 138 [Ru(bipy)?(Sbipy)l*', photoproperties, a 180 RuCO', Ru(CO),. Ru(CO).;, IR spectra, a 40 UG-2 Reef, geology. Pt and Pd reserves 33, 105 Ru(dcbpy)dNCS)z, as Graetzel standard. a 136 Ru(dcphen)2(NCS)2,photosensitiser for Ti02,a 136 Vinyl Acetate, asymmetric hydroformylation. a 44 [RuHCI(PPr'Al, Grubb's catalyst intermediate, a 182 Vinyl Arenes, asymmetric hydroformylation, a 44 Ru(I1) porphyrin-Memfield's peptide resin, a 181 Vinylation, iodobenzene, a 138 Ru(II1) P-diketone butadiyne polymer, a 41 Vitamin E, synthesis, a 182 [Ru(L)312+dyes. for luminescent Nation membranes, a 42 VOCs, oxidation, a 87, 138 RuX(EPh3) Schiff base complexes, a 140 sensor 57 Ruthenium Compounds, Pr3Ru0,, magnetism, a 179 WBST/RuOl capacitors, a I40 Water, for H2 generation, a 137, 140 Ru2Ge3,Ru2Si3, optical spectra, a 135 nitrate removal 43.84 RuI(CO)U,decomposition, Ru particles, Ru02 films, a 87 oxidation, a 44 as solvent, for catalytic reactions 138. 168 Schottky Diodes, AulPtlGaN, properties 157 Water Gas Shift Reaction, nanostructured PGM catalysts 3 Sensors, bio-, hypoxanthine, a 181 CH,, a 87 Zirconium, ZrPdA, synthesis and properties, a 86
Phtimm Metub b.,2000,44, (4) 196