INORGANIC AND COORDINATION CHEMISTRY559595

doi:10.2533/chimia.2008.595 CHIMIA 2008, 62,No. 7/8

Minisymposium Inorganic and Coordination Chemistry 149 Minisymposium Inorganic and Coordination Chemistry 150

Playing with anions: 1) Fast, environmentally friendlyruthenium- Reticular Chemistry allylation catalystsand 2) Understandingand predicting ion pairing. Omar M. Yaghi

Paul S. Pregosin University of California, Los Angeles (UCLA) 607 Charles E. Young Dr. East Los Angeles,CA90095-1569 USA ETH Zurich, 8093Zurich, Switzerland This chemistryisconcernedwithlinkingorganicand inorganic molecular The lecture will consist of two separate but related themes. The opening building units into extended structures usingstrong bonds. These structures section will involve ashort excursioninto how one can synthesize new, and arecrystalline andhaveframeworks in which the inorganic units act as optimize old, rutheniumbased homogeneous allylation catalystssuch that ‘joints’ and the organicunits as ‘struts’ to produce highly porous and robust they are rapid, environmentally friendly and demonstrate exceptional metal-organic frameworks (MOFs) andzeolitic imidazolate frameworks regioselectivity,and then finish with an NMR approach designed to show (ZIFs). This presentationwill outline asimpledesign strategyand synthesis howtorecognize, understand and even predict the extent of ion pairing in a of these materials including their adsorptiveproperties and applicationsto wide variety of inorganic, organic and organometallic salts. clean energy.

Inorganic and Coordination Chemistry 151 Inorganic and Coordination Chemistry 152

Multitopic Ligand Approach for theSynthesis of New Mixed Metal StericallyVery Demanding Cyclopentadienyl Ligands: Significant Compounds Changes in the Behavior of Ru Half-Sandwich Complexes

FabienneGschwind, Katharina M. Fromm* Barnali Dutta,Kay Severin

University of Fribourg,CheminduMusée 9, CH-1700 Fribourg, Institut desSciences et Ingénierie Chimiques, EcolePolytechnique Fédérale Switzerland de Lausanne (EPFL), CH-1015 Lausanne, Switzerland

Today, the demand for new materials (superconductors,opto-electronic de- Rutheniumhalf-sandwich complexes with new cyclopentadienyl ligands vices, etc.) is steadily growing. Complexes of alkaline and earth alkaline (Cp^) have been prepared through an unprecedented Ru-catalyzed [2+2+1] metal ions mayfor example provide precursorsfor the synthesis of high-Tc cyclotrimerization reaction of tert-butylacetylene in methanol or ethanol.[1] superconductors[1, 2]. We propose the development of newheterometallic complexes with tailoredelectronic,optical and/or magnetic properties. H ♦ Onepot synthesis Combining different metal ions in molecular devices and analyzing their H Cl Cl RO ♦ Sterically demanding ligands behavior, is interesting for later applications, and also of fundamental inter- 55 °C Ru RuCl (solv.) + Ru est[3].For this purposewedevelopedamultitopic ligand system based on 3 n OR Cl ♦ Versatilestartingmaterials ROH H open polyethermolecules, which allows the coordination to different metal Cl ion types by different ligating atoms. R=Me,Et The complexes have shown distinctreactivity in stoichiometric and catalytic O O O 1. Oxalylchlorid O O O O Toluene O O O O transformations arising from the steric demand of the π-ligand. Noteworthy M O O M1I2 M1 M2I2 O 1 - - [2] 2 OH + O O O O O O O O O O O are the interplay between16e and 18e Ru-phosphine complexes. Excep- 2. Triethyamin solvent solvent N OH HO Toluene II N N N N tionalreactivity of [Cp^Ru(μ-OMe)] includes formationofCl-bridged Ru reflux,6h N N M2 2 I I dimersinstead of tetramers, unprecedented transformation of cyclooctadiene into ethylbenzene in the coordinationsphere of Ru, CO insertion in prefe- rencetoaddition and high catalytic activity forATRC reactions on awide We will showthat this concept worksbypresenting firstresults. With alka- rangeofsubstrates like N−substituteddichloro-and trichloroacetamides, lineearth metal ions such as calcium, the ligand wraps around the metal ion, [3] enamides,ethers and esters. [Cp^Ru(PTA)2]possesses increased cytotox- yielding acomplex in which the nitrogen atoms are orientedsuch as to ac- icity on human ovariancancer cell lines compared to its Cp analogue.[4] commodate another metal ion such as transition metals. [1]S.Gauthier,E.Solari, B. Dutta,R.Scopelliti,K.Severin Chem.Commun. 2007,1837 [2]B.Dutta, E. Solari, S. Gauthier, R. Scopelliti, K. Severin Organometallics 2007, 26, [1]K.M.Fromm, Dalton Transactions, 2006, 43,5103-5112. 4791 [2] R. C. Mehrotra, A. Singh,M.Bhagat, Journal of Sol-Gel Sciences [3]B.Dutta, R. Scopelliti, K. Severin Organometallics, 2008, 27,423. and Technology, 1998, 13,45-49 [4]B.Dutta, C. Scolaro,R.Scopelliti, P. J. Dyson,K.Severin Organometallics, 2008, 27, 1355. INORGANIC AND COORDINATION CHEMISTRY559696 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 153 Inorganic and Coordination Chemistry 154

Efficient allylation of indolesand pyrroles with allyl alcohols catalyzed Electron tunneling through rigid rod-like bridges by complexes derived from [Cp*Ru(NCMe)3](PF6): catalysis, structure and mechanism David Hanss,Mathieu Walther, Oliver S. Wenger*

Alexey B. Zaitsev,Stefan Gruber, Paul S. Pregosin Department of Inorganic, Analytical and Applied Chemistry, University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland ETH Hönggerberg, Wolfgang-Pauli-Str.10, CH-8093 Zürich, Switzerland Photoexcitationofarhenium complexwith acovalently attached phenothia- Dicationicruthenium(IV) allyl complexes areefficient catalysts in theFrie- zine triggersanintramolecular electrontransfer that occurs via atunneling del-Crafts allylation of phenolsand indoles.1,2 We have found that mechanism.Time-resolved luminescence and transientabsorption spectros- [Cp*Ru(NCMe)3](PF6)together with selectedacidco-catalysts in thepres- copy are used to extract information on both the photoinduced (forward) and ence of allylalcohols allows for in situ formationofη3-allyl Ru(IV) com- thermal(backward) electron tunnelingrates. plexes that efficiently catalyze the reaction of indoles and pyrroles with allyl alcoholstoform3-allylindoles and 2(5)-allylpyrroles, respectively,under mild conditions in high yield and regioselectivity. Ar

[Cp*Ru(NCMe)3](PF6)(5mol %) R2 Ar HA (5 mol%) R2 Ar R2 + MeCN, r.t. + N OH N N R1 R1 R1 HA -Brønstedacid

Aspects of the catalysis, structure andmechanismwill be presented.

1 I. Fernandez, R. Hermatschweiler, F. Breher, P. S. Pregosin, L. F. Veiros, Moleculeswith up to five p-xylenespacers have been prepared in good M. J. Calhorda,Angew. Chem., Int. Ed. 2006, 45,6386. yields. 2 A. B. Zaitsev,S.Gruber, P. S. Pregosin, Chem.Commun. 2007,4692. Of key interest to us is the question how the electronic structure of the cova- lent bridge between the donor and theacceptor affects the electron tunneling rates.

Inorganic and Coordination Chemistry 155 Inorganic and Coordination Chemistry 156

AMacrocylic Triruthenium(II)Complex Mononuclear Organometallic Pt(II) Complexes and Pt(II)-Cu(I)Mixed- Metal Complexesfrom Pyrazolate BasedCompartmental Ligands Roesel, P.; Zampese, J.; Schaffner, S.; Neuburger, M.; Housecroft, C. E.; Constable E. C. Marc-Etienne Moret and Peter Chen

Department of Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel, ETHZ, Wolfgang-Pauli-Strasse 10, 8093 Zürich, Switzerland Switzerland. In an effort towards the use of bimetallic cooperative effects in the field of Ruthenium(II) complexes containingpolypyridine ligands continue to at- platinum(II) mediated C-H activation[1], we synthesized mononuclear com- tractconsiderable interestbecause of their appealing photophysical proper- plexes of 3,5-bis(iminoacetyl)pyrazolate ligands[2] incorporating the tiesand their incorporationinto light-activated devicesorphoto-activated [Pt(II)Me(SMe2)], [Pt(II)Ph(SMe2)] and[Pt(II)Ph2]fragments. The coordi- molecularmachines. nation of these complexes to Cu(I)was studied, affording heteropolymetal- Herein we describe the synthesis of amononuclear ruthenium(II)complex 1, liccompounds[3]. Thesewere structurallycharacterized,and their dynamic and its cyclic trinuclear homologue 2.Bothcomplexes can be synthesized properties in solution were studied by variable temperature 1HNMR. Dative in high yields (90%) startingfromthe corresponding ligands and [cis- Pt(II)-Cu(I) bondsand cuprophilic interactions were observed in the Ru(bpy) Cl ]and are kinetically and thermodynamically stable. 2 2 [Pt(II)Ph2]containing structures.

Ar Ar S Pt N CuCl2 ArN Pt NAr Pt NAr N N H N N Cu N N Cu N N N N N Ar Cu N Redox and UV-Vis and fluorescence spectroscopic properties of both com- N N NAr Pt S Ar Ar N plexes have been investigated, and the results will be presented. Ar

Ar-=4-MeOC6H4-, 2,6-Me2C6H3-

[1] Balzani, V.; Scandola,F.Supramolecular Photochemistry,Horwood, Chichester, 1991. [1]M. Lersch, M. Tilset, Chem. Rev., 2005, 105, 2471. [2]Balzani, V.; Campagna, S.; Denti, G.;Juris, A.; Serroni, S.; Venturi, M. [2]G. Noël, J. C. Röder, S. Dechert, H. Pritzkow,L.Bolk, S. Mecking, F. Acc. Chem.Res. 1998, 31,26. Meyer, Adv. Synth. Catal., 2006, 348, 887 [3] Badjic,J.D.; Balzani, V.; Credi, A.; Silvi, S.; Stoddart, J. F. Science [3] M.-E. Moret,P.Chen, Submitted. 2004, 303,1845, and refs. therein. INORGANIC AND COORDINATION CHEMISTRY559797 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 157 Inorganic and Coordination Chemistry 158

ColourimetricSensing of Cyanide with Vitamin B12 Dramatic conformational changeinthe enzymemethyl-coenzyme M reductase(MCR) when the coenzyme Banalogue CF3-S-CoB binds to Felix Zelder*, Christine Männel-Croisé, the active NiI state University of Zurich, Winterthurerstr. 190, CH-8057 Zurich, Switzerland Sieglinde Ebner,Bernhard Jaun, Meike Goenrich, Rudolf K. Thauer, The detectionofcyanide in water is of particular importance since this toxic anion is Dariush Hinderberger, and Jeffrey Harmer widely used in many industrial applicationslike mining, electroplating and metal-

lurgy [1]. The toxicityarises from thebinding of cyanide to cytochrom a3 thatinac- ETH Zürich,Wolfgang-Pauli-Str. 10, 8093 Zürich, Switzerland tivates the cellular respiration and affects the central nervous systems [2]. Recently, the development of artificial sensors for the so called `nakedeye`detection of cya- Methaneformation by methyl-coenzymeMreductase requires binding of nide has attracted much attention [3][4], but most of these methods confront the the two substrates methyl-coenzymeM(CH3-S-CoM)and coenzymeB(H- drawback of poor water solubility as well as interference with many common anions S-CoB). We have synthesized the coenzyme Banalogue CF3-S-CoB and especially certain halides. obtained thefirst structuralinformation on the enzymeinthe activeNiIoxi- red red violett dation state when the substrate CH3-S-CoM andthen H-S-CoB bind to the CN CN CN protein. Co - Co Co X CN- CF -S-CoB 3 – F F O COO CN OPO – N N S N 3 F H N N N HOOC F430 O HS-CoM N HS – SO3 H2NOC H HN COOH N N CH3-S-CoM ------3- 2- - - NiI X :F,Cl,Br,I,SCN ,NO3,ClO4 ,HCO3 ,PO4,SO4 ,AcO ,PhCOO N N COOH S H C SO – H 3 3 HOOC Recently, we demonstrated that commercial vitamin B12 is useful for the detection of O HS-CoB O COO– O – millimolar cyanide in water [5]. The mode of operation of this sensor is controlled by OPO3 H2N COOH HS N its natural benzimidazole trigger able to switch between different conformational C H α'147 states. In different competition experiments, it was shown that various other anions Gln as well as athousand fold excess of Cl- over CN- do no interferewith the sensor. In This information is obtainable with the substrate analogsH-S-CoM +CF3- the moment we focus on different approaches to improve the sensitivity of these S-CoB and the measurement of the 19F(I=½)hyperfine interactions to corrin basedsensors. determine theorientation and locationofthe CF group of CF -S-CoB. Us- [1] (a) S. I. Baskin, T. G. Brewer Medical Aspects of Chemical and Biological Warfare;Eds.: F. 3 3 Sidell, E. T. Takafuji, D. R. Franz; TMM Publications: Washington DC, 1997,271-286. (b) ingW-band CW-EPR andENDOR, it was possible to deduce the distance Ullman`sEnzyclopediaofIndustrial Chemistry,Wiley-VCH: New York, 1999. betweenthe nickel center of thehydrocorphinF430and thefluorine atoms [2] Cyanide in biology;Eds.: B. Vennesland,E.E.Comm, C. J. Knownles, J. Westly, F. Wissing; in theCF3-group.Ifthe geometry within the active siteremained as found in Academic Press: London, 1981. II [3] A. Metzger, E. V. Anslyn Angew. Chem. Int. Ed. 1998, 37,649-652. thecrystalstructure of inactive Ni -forms of the enzyme, this distance [4] C.-F. Chow, M. H. W. Lam, W.-Y. Wong Inorg. Chem. 2004, 43,8387-8393. should lie in the range of ca. 0.65-0.76 nm for the three Fatoms, respective- [5] F. Zelder, Inorg. Chem. 2008, 47,1264-1266. ly. In fact, adistance of less than 0.46nmwas found, which brings it within van der Waals contact to thesulfur of coenzymeM.

Inorganic and Coordination Chemistry 159 Inorganic and Coordination Chemistry 160

Abnormal NHCComplexesofRhodium: Synthesis and Catalytic Labeling Thiele’s acid with Re(I)/Tc(I) triscarbonyl through Activity in TransferHydrogenation retro-Diels-Alder Reaction in aqueous media

AnnekeKrüger,Liangru Yang, Antonia Neels, Martin Albrecht Y. Liu,P.Schmutz,B.Spingler, R. Alberto

Department of Chemistry, University of Fribourg, Ch. du Musée 9, InstituteofInorganic Chemistry, University of Zürich, Winterthurerstr. 190, CH-1700 Fribourg, Switzerland. CH-8057, Zürich, Switzerland

Imidazolium-derivedcarbenes thatare bound to the metal centre via C4 The amino acids coupled with tripodal Dap (Diaminopropionic acid) has (abnormal NHCs) haverecently becomeknown to have better electron do- been introduced in our group to prepare Re(I)/Tc(I) tri-carbonyl complexes, norproperties than their normal, C2-bound analogues [1][2]. which can be recognized and transported by LAT1transporter[1]. Based upon this observation, Cp (Cyclopentadiene), with its smaller and more We have now shown that abnormal NHC complexes of Rh,such as 2 and 3, compact size than Dap, should be agood chelator candidate for Re(I)/Tc(I) can be synthesisedbydirect metallation, using either Rh(I) or Rh(III)pre- tri-carbonyl chemistry. Contrary to the conventional view moisture sensitive cursors [3].The catalytic activity of the abnormal Rh dicarbene complexes chemistryofCp, C5H5COOHcan react withRe(I)/Tc(I) triscarbonyl to 99m in transferhydrogenation is far greaterthan that of their normal analogues. produce (CO)3MC5H4COOH (M=Re(I), Tc(I)) in aqueous media We have demonstrated that transferhydrogenation catalysed by these Rh (Scheme). What is more,the Diels-Alder dimer of C5H5COOH, Thiele’sacid, complexes proceedsvia amonohydride mechanism,thus allowing for regi- reacting with Re(I)/Tc(I) triscarbonylaswell in aqueous media, results in the oselective transfer of hydrogen. formation of (CO)3MC5H4COOH(Scheme), which gives afirst example of R' retro-Diels-Alder complexation of triscarbonyl compound at low temperature I N I I R' I o R R' I I R' I (<100 C) [2]. I R N N N N Rh Rh R N NCMe R N N Rh COOH N I N N NCMe N R N N N I R R R COOH COOH N R' R' R' [Re(CO) ]+ 99m + I 3 or [ Tc(CO)3] R' Re Tc 12 3O O 170oC HOOC 95oC O O O COOH O hydrothermal water [1] A. R. Chianese, A. Kovacevic, B. M. Zeglis, J. W. Faller, R. H. Crabt- Thiele'sAcid ree, Organometallics, 2004, 23,2461. Scheme [2] M. Heckenroth, E. Kluser, A. Neels, M. Albrecht, Ang. Chem.,Int. Ed., 2007, 46,6293. [1] Y. Liu, J. K. Pak,P.Schmutz,M.Bauwens,J.Mertens, H. Knight,R. [3] L. Yang, A. Krüger, A. Neels, M. Albrecht, Organometallics, 2008, 27, Alberto, J. Am.Chem. Soc., 2006, 128,15996-15997 in press. [2] Y. Liu, B. Spingler, P. Schmutz, R. Alberto, J. Am. Chem.Soc., 2008, 130,1554-1555 INORGANICAND COORDINATION CHEMISTRY559898 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 161 Inorganic and Coordination Chemistry 162

Development of Heterogeneous Catalysts using DNA Recognition by Water Soluble Multi –Porphyrin Arrays Automated High-Throughput Tools Philipp M. Antoni,Bernhard Spingler AmiraAbou-Hamdan, Ph.D. Chemspeed TechnologiesAG, Rheinstrasse 32,CH-4302 Augst (BL),Switzerland University of Zürich, Winterthurerstr. 190,CH–8057Zürich, Switzerland High-throughput tools for the preparation of heterogeneous catalysts are just evolving. However, known techniques such as the impregnation of support wafers Cationicmetalporphyrins can interact with DNAinvarious ways. Most with metal salt solutions are often not applicable for industrial purposes,where a commonly, thesesystemsintercalate into DNA. The zinc porphyrins subsequent scale-up and commercialization of the developed catalyst is 4+ predetermined. The catalysts prepared in the high-throughput scale have to ZnTMPyP was postulated to coordinatetothe N7-guanineofZformof [1] represent the very complex structures and characteristics of commercial poly d(GC) .Wehave shown that Z–DNA can be inducedbymononu- heterogeneous catalysts, including for example metal dispersion and distribution, clearmetal complexes having eitherNi(II) or Zn(II) centers[2] or by dinu- support material, oxidation state of the active compound etc. From the Technical clearmetal complexes[3]. Scale to High-Throughput: Due to the complexity of heterogeneous catalyst Combining thosetwo ways in influencing DNA, we will show acombina- preparation, only few variables can already lead to ahuge amount of catalyst, tion of these systemsinorder to observe amore selective coordination be- requiring high-throughputfor both preparation and screening. By using the haviourtowards certain DNA conformations. We want to introducearecog- synthesis robot based on the Chemspeed Accelerator platform, up to 24 nition unit consistingofmultiple metal porphyrins linked by metallic link- heterogeneous catalysts can be prepared in parallel on a3-15 gram scale, automatically performing tasks such as co-precipitation of mixed metal oxide ers. The different coordination spheres of thelinking metal centers such as catalysts as well as impregnation of supports with different metal salts. Pt(II), Re(I)will further modulate thecoordination behaviour towards dif- Downscaling of industrial techniques is easily feasible. ferent DNAdoublehelices conformations.

[1] M. Balaz, M. De Napoli, A. E. Holmes, A. Mammana, K. Nakanishi, N. Berova, R. Purrello, Angew. Chem.Int. Ed. 2005, 44,4006. Selectivi ty [2] B. Spingler, C. Da Pieve, Dalton Trans. 2005,1637.

Benchmark(commercialCatalyst) [3] B. Spingler, P. M. Antoni, Chem. Eur. J. 2007, 13,6617.

Deviations in Preparation

identical Catalysts in 10 gScale

C The preparation of heterogeneous catalysts by automated means, allows for the fully automated and unattended screening of awide range of experiments under highly demanding conditions Furthermore, the obtained results give evidence, that an accelerated, automated development of commercial catalysts is possible and typical development times are significantly reduced by at least 50%.

Inorganic and Coordination Chemistry 163 Inorganic and Coordination Chemistry 164 Sawhorse-Type Diruthenium Complexes Containing Porphyrin- Cu/Zn Superoxide Dismutase- Mimics: Is There aStructure-Activity Derived Ligands Relationship for the Metal Binding Region?

Mathieu Auzias,a Bruno Therrien,a GeorgSüss-Fink,a L. Juilleret- Vimalkumar Balasubramanian,Cornelia G. Palivan Jeannerat,b F. Schmitt b Chemistry Department,University of Basel, Klingelbergstrasse 80, CH- a InstitutdeChimie, Université de Neuchâtel, CH-2009 Neuchâtel b University Institute of Pathology,CHUV,CH-1011 Lausanne 4056 Basel,Switzerland

Diruthenium tetracarbonyl complexes of the typeRu2(CO)4(O2CR)2L2 are Cu/Zn Superoxide dismutase (SOD), one of the metalproteins whichact as known to have astable Ru2(CO)4 backbone in asawhorse-type arrangement an antioxidantenzyme can not be directlyadministrated, due to its very low [1]. To thebest of our knowledge, such complexes have never been studied bio distribution. One way to solve this problem is to use low-molecular as antitumor drugs. Given the promising results with arene-ruthenium por- mass copper complexes, which have SOD-like activity (SOD-m). Despite phyrin derivatives [2], we decided to design dirutheniumcomplexes based the intensive effortswhichhave been made to obtaincompounds with high on the Ru2(CO)4 sawhorse unit containing porphyrin-derived ligands for SOD-like activity,there are no studieswhich try to connect the biological photodynamic cancer therapy. activity of all these compounds to their structural properties, in order to modeland understand the conformationswhich promote abetteractivity.

H3C CH3 We constructed adatabase with the classesofSOD-m previouslyreported in C C theliteraturebytakinginto accountmagnetic resonance, spectroscopiccha- O O NH N O O N HN racterization, and activitytests. We did astatistical data analysis by taking N Ru Ru N into account various parameters, such as d-d transitions in electronic spectra, N HN NH N C C C C O OO O hyperfine coupling constants, distortion factor of the geometry around the metal, and coordination number of copper, in connectionwiththe SOD-like activity. We found outthat the mostactivecopper complexes were mono- nuclear with four-coordination sphere around themetal, and that they be- long to a.particular range of structural region whichincludes d-d transition The synthesis and the photodynamic anticancer activities of these complex- region (550-680 nm), hyperfine coupling constants (120-160 G), and adis- es will be discussed. torted geometry which corresponds to adistortion factor of 130-170 cm. We could establish that each structuralparameter alone does not have much [1]H.Schumann, J. Opitz, J. Pickardt, J. Organomet. Chem. 1977, 128, influence on activity, but when theyare interrelated together astructure- 253-264. activity relationship can be obtained. [2] F. Schmitt, P. Govindaswamy,G.Süss-Fink, W. H. Ang, P. J. Dyson, L. Juillerat-Jeanneret, B. Therrien, J. Med. Chem. 2008, 51,1811-1816. INORGANIC AND COORDINATION CHEMISTRY559999 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 165 Inorganic and Coordination Chemistry 166

Crystal Engineering with Extended {M(tpy)2}(tpy =2,2':6',2''- Microwave-Assisted Non-Aqueous Sol-Sel Routes terpyridine) Units: Coordination Polymers and Networks to Metal Oxide Nanoparticles

Jonathon E. Beves,Edwin C. Constable, Emma L. Dunphy, Catherine, E. Idalia Bilecka,Pierre Elser, Igor Djerdj, Markus Niederberger Housecroft, Markus Neuburger, Silvia Schaffner, Jennifer Zampese Department of Materials, ETH Zürich, Wolfgang-Pauli-Strasse 10, Department of Chemistry,University of Basel, Spitalstrasse 51, 4056 Basel. 8093 Zürich, Switzerland

2,2':6',2''-Terpyridine complexesoften possess interesting electrochemical Non-aqueous sol-gel routes offer asimple one-pot approach to alarge varie- or photophysical properties. The inclusion of these groups into extended ty of highly crystalline metal oxide nanoparticles at moderate temperatures structures offers the opportunity to build useful functionality into molecular [1]. These routes involve the chemical transformation of metal organic pre- frameworks. cursors in organic solvents making use of simple organic reactions (see Scheme below). Combination with microwave irradiation increases the rate 2+ N N 2+ 2+ of nanoparticle formation and directly influences the organic reaction path- NN N ways. This results on the one hand in an immense acceleration of the NH N process, and on the other hand provides apowerful tool to control the size of N N N N N the metal oxide nanoparticles by adjusting the experimental conditions such ~7 Å Ru ~18 Å N N N N N N Ru Ru N N N N as concentration, time and temperature. N N N N

HN N N NN

N Using self-complementary hydrogen bonding or metal ions, such as Ag(I) or Cu(II), as bridging motifs we are developing [1-3] coordination polymers Asimple and general approach for the preparation of metal oxide nanopar- ticles in good yields within minutes or even seconds is presented, offering and networks including {M(tpy)2}groups. great opportunities for tailoring the crystal size as well as for the develop- [1] J. E. Beves,. E. CConstable, C. EHousecroft, C. J. Kepert, D. J. Price, ment of predictable size-control strategies [2]. CrystEngComm, 2007, 9,456. [2] J. E. Beves, E. C. Constable, C. E. Housecroft, C. J. Kepert, M. Neu- [1] Niederberger M., Nonaqueous sol-gel routes to metal oxide nanopar- burger, D. J. Price, S. Schaffner, CrystEngComm, 2007, 9,1073. ticles, Acc. Chem. Res. 2007,9,793. [3] J. E. Beves, E. C. Constable, S. Decurtins, E. L. Dunphy, C. E. [2] Bilecka I., Djerdj I. and Niederberger M., One-minute synthesis of Housecroft, T. D. Keene, M. Neuburger, S. Schaffner, CrystEngComm. crystalline binary and ternary metal oxide nanoparticles, Chem.Com- 2008, in press. mun. 2008,886.

Inorganic and Coordination Chemistry 167 Inorganic and Coordination Chemistry 168 Acetonitrile exchange kinetics on di- and trivalent lanthanide ions New Efficient Pincer-Type Heck-Catalysts –Mechanistic Investigations

Gabriella Bodizs,LotharHelm Jeanne L. Bolliger,Olivier Blacque, and Christian M. Frech*

Institut des SciencesetIngénierieChimique, Ecole PolytechniqueFédérale University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland de Lausanne,BCH,1015 Lausanne, Switzerland The Heckcross-coupling reactionisone of the most efficientmethodsfor Our study reports results relatedtothe acetonitrile exchange reaction on C-C bond formation, which is in our days an indispensable tool in organic somehomoleptic lanthanide complexes: [Ln(CH3CN)n][Al(OC(CF3)3)4]z (n synthesis for the catalyticformation of symmetric and non-symmetric =9,Lnz+ =Nd3+,Gd3+,Dy3+ and Eu2+;n=8,Lnz+ =Tm3+). During the ex- olefins. change reaction an acetonitrile molecule from thefirst coordination sphere of Ln’s is replacedbyanother one from the bulk. The kinetic parameters as R [Pd] R wellasthe electron spin relaxations and the rotational correlation times X + R' + Base + [HBase]X were obtained by variable temperature 14NNMR, 1HNMRDand EPRtech- R' niques.Asystematicincreaseofthe acetonitrile exchange rates as the lan- We would liketointroduce new palladium pincer-type complexes as thanideionic radii decrease has been established. This behavior was inter- extremely efficient Heck-catalysts which are able to couple aryl bromides preted by theincrease in the steric crowding produced by thecoordinated and aryl chlorides with various olefins. CH CN molecules to themetal center. 3 The syntheses of these palladium complexes require only cheap starting Up to now, theelectronic relaxation 0.3 materials and can be carried out within one day. timesfor lanthanide ions(other than 3+ Additionally, mechanistic investigations regarding the nature of the active 0.25 Gd )have been determined only in [1,2] species were performed, because since pincer-type complexes have been 0.2 aqueous solution. Since they play

1 successfully introduced as highly efficient catalysts in the Heck reaction, it s acrucialrole in the estimation of the −1 M 0.15 solventexchange rates it seemed to has been discussed whetheraPd(II)/Pd(IV) mechanism or theformationof /m 1

r palladium nanoparticles leads to their high catalytic activity. 0.1 be worthtodetermine the electronic

0.05 relaxation timesoflanthanide ions in anhydrous acetonitrile. It has been 0 10−2 10−1 100 101 102 103 found that the electronic relaxation 1 ν ( H) /MHz times of lanthanide ions are indepen- 1HNMRD profile of the of the Dy3+ ion in an- dent from thenature of the coordi- hydrous acetonitrile at 298 K. nated solventmolecules. [1]I.Bertini,F.Capozzi,C.Luchinat, G. Nicastro, Z. Xia, J. Phys.Chem. 1993, 97, 6351 [2] L. Helm, A. E. Merbach, Chem. Rev. 2005, 105, 1923 INORGANIC AND COORDINATION CHEMISTRY660000 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 169 Inorganic and Coordination Chemistry 170

99m + Gold NanoparticlesFunctionalized with Liquid-Crystalline Synthesisofhigh valent [ TcO3] complexesand [2+3] cycloaddition Dendrimer-Thiols reactions with alkenes in water as anovel direct labelingstrategy

JulienBoudon,StéphaneFrein, ToralfScharf, Georg Süss-Fink, Henrik Braband,Yuji Tooyamaand Roger Alberto Thomas Bürgi andRobert Deschenaux University of Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland

University of Neuchâtel, 99m Institutes of Chemistry, Physics and Microtechnology, The labeling of small biomolecules with Tc under retention of bioactivity is the major challenge in modern radiopharmacy. For this reason we devel- Rue Emile-Argand 11, CH-2009 Neuchâtel, Switzerland oped in thepast two different syntheticapproachesfor thesynthesis of 99 [1] { TcO3}complexes, via an oxidation pathway in water andbythe direct 99 -[2] Gold nanoparticles have generated agrowing interest in thepast two dec- activation of [ TcO4] in organic solvents to study stabilityand properties ades due to their metallic properties andpotential applications [1]. We pro- of this newtypeofverysmall complexes. In contrasttothe 99Tc chemistry posed gold particlesstabilized by liquid-crystalline thiolato-dendrimers in the synthesis of 99mTc complexes for radiopharmaceutical application hasto 99m - 99m ordertoobtain materials with temperature-dependent optical properties as it start form[ TcO4] in water, therefore the synthesis of { TcO3}com- plexes is much more challenging. was observed with mesomorphic fullerene-and ferrocene-containing den- 99m 3 +/0 Here we report about the first syntheses of complexes [ TcO3(N -R)] drimers [2]. (N3-R =triazacyclononane and its derivatives) directly from aqueous solu- NaBH4 HAuCl4·3H2O+TOAB tion. Thesecomplexesare stable at 37° Cinwater andinthe presence of + Au S HS-C H 99m 12 25 Toluene, r.t.,24h,30% n serumproteins and represent anovel kind of Tc complex for labelling 99m 3 +/0 O CH2Cl2 purposes. Furthermore, the [ TcO3(N -R)] type complexes react with O (CH ) O CO CN r.t.,72h 2 10 2 under Argon alkenes in water by a[2+3] cycloaddition, thereby formingthe correspond- 50% HS (CH2)10 CO2 ingglycolato complexes at areasonable rate.Wecall this “clack chemistry” O (CH2)10 O CO2 CN S [3] O duetothe principalsimilarity with the well known “click chemistry”. m O Au NC O C O (CH ) O “Clack chemistry” represent anovel way of labelling. Substitution does not 2 2 10 take place at the metal centre as commonly encountered but on the ligands O2C (CH2)10 S

NC O2C O(CH2)10 O activated by the metal centre. p O R R R R R R These materials were obtained by exchanging stabilizing-alkylthiolligands "clack" forthe appropriate liquid-crystalline dendrimer-thiol. As the first attempts Tc + Biomolecule Tc O O O O forlower generation dendrons did not show aclear mesomorphic behaviour, O O higher-generation dendrimers of this type will be studied in nextexperi- Biomolecule ments and thus thermic behaviour of these new materials will be discussed. [1] H. Braband, U. Abram, Inorg. Chem. 2006, 45,6589. [1]M.C.Daniel, D. Astruc, Chem. Rev. 2004, 104 (1), 293-346 [2]Y.Tooyama, H. Braband, B. Spingler,U.Abram,R.Alberto, Inorg. Chem. [2]a)Gottis et al., Helv.Chim. Acta 2007,957; b) Lenoble et al., J. Am. 2008, 47,257. [3]H.C.Kolb, M.G. Finn,K.B. Sharpless, Angew. Chem.Int. Edit. 2001, 40, Chem.Soc. 2007,9941; c) Campidelli et al., J. Mater.Chem. 2008, 2004. 1504

Inorganic and Coordination Chemistry 171 Inorganic and Coordination Chemistry 172

AntimicrobialSurfaces Palladium-Catalyzed Enantioselective Allylic Phosphination

Priscilla S. Brunetto,KatharinaM.Fromm* Pietro Butti,Raphël Rochat, Aaron D. Sadow, Antonio Togni*

University of Fribourg, Chemin du Musée 9 Dept. of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich CH-1007, Fribourg, Switzerland Palladium-catalyzed allylic substitution reactions are known to occur with a variety of carbon, nitrogen and oxygen nucleophiles. However, to the best All commonly used implantmaterials, metals and polymers, seem to present of our knowledge, the analogous reaction involving asecondary phosphine acommon problem:bacterialadhesion on their surfaces, mainly Staphylo- has never been reported. Recently, our laboratory reported that dicationic cocci. The resultant biofilmisresistanttoaggressivepharmacological Nickel complexes catalyze the intermolecular hydrophosphination of vinyl agents as well as host defences [1]. nitriles with secondary phosphines in good yield and high enantiomeric Oneway to prevent the establishmentofinfection is to render the implant excess [1]. We now found that the same type of nucleophiles may be used surface bactericidal, creating astableenvironment with aspectrumsimilar for an unprecedented allylic phosphination. Thus, the model substrate 3- to the soluble antibiotics [2]. The current revivalofsilver chemistry in this acetoxy-1,3-diphenylprop-1-ene (1) is converted with diphenylphosphine to context initiated us to usethis metal ion for coating purposes [3]. the corresponding allylicphosphine (2) in the presence of 5mol-% of aPd catalyst containing the ferrocenyl ligand Josiphos (3) [2].

PCy2 Cat.Pd0/L* OAc PR2

R' R' R' R' L*= Fe PPh2 The combination of molecules derivedfrom antibioticsand silver com- pounds would provide additive, synergic activity against most micro- rac. up to 96%ee organisms,and thus the desired protection. Therefore, we propose to avoid or at leaststrongly reduce bacterial adhesion to implantsurfaces usinga series of newlydeveloped Ag-antibiotic combinations on implant surfaces. Product 2isisolated in quantitative yield and the enantioselectivity is up to 96 %ee. This new C-P bond forming reaction can provide abroad set of chiral phos- [1]P.S Stewart, J.W.Costerton, Lancet. 2001,358, 135. phines with the opportunity of further functionalization of the alkene. [2] B. Jose, V. Antoci, A. R. Zeiger, E. Wickstrom, N. J. Hickok Chemis- try &Biology. 2005,12, 1041. [1] A. D. Sadow, A. Togni, J. Am. Chem. Soc. 2005, 127, 17012. [3] J. L. Clement, P. S. Jarret, Metal-Based Drugs. 1994,467. [2] A. Togni, C.Breutel, A. Schnyder, F. Spindler, H. Landert, A. Tijani, J. Am. Chem. Soc. 1994, 116, 4062. INORGANIC AND COORDINATION CHEMISTRY660101 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 173 Inorganic and Coordination Chemistry 174

Chiral Ferrocenyl AmidinesasModular Ligands for NOVELCHIRALCOMPLEXES INCORPORATING Asymmetric Catalysis ROTATIONALLY RESTRICTEDLIGANDS

FrancescoCamponovo,Sebastian Böhringer,Antonio Togni Chwalisz P.,Constable E. C., Housecroft C. E., Chow H.S.

Department of Chemistry and Applied Biosciences, ETH Zürich, Department of Chemistry,University of Basel, Spitalstrasse 51, 8093 Zürich, Switzerland CH-4056, Basel, Switzerland.

Amidine1 andespecially amidinato2 ligands have been widely used in transi- n+ tion metal and in main group chemistry. However, their application in ho- The {M(tpy)2} (tpy =2,2':6',2"-terpyridine) motif is increasingly used in 2+ mogeneous enantioselective catalysis remains very rare. preference to {M(bpy)3} (2,2'-bipyridine) domains in supramolecular 2+ We present here the shortand highly modular synthesis of new chiral ferro- chemistry.[1] One major reason is that {M(bpy)3} is chiral and the incor- cenyl-substituted amidines combining an amine (1,2), apyrazole (3,4)ora poration of multiple centres givesrise to diastereoisomeric structures. This n+ phosphine (5,6)with an amidine unit as donors. is nottosay that {M(tpy)2} motifs cannot be chiral; the commonest ste- reogenic factor is the desymmetrization of the ligand by substitution on one X X X R1,2 of the two terminal rings. We recently demonstrated that asymmetrical li- 1 i NR NMe2 Pr : (R,Sp)-1 gandslinked through flexible chains can also give rise to chiral structures as Li NMe2 Cy : (R,Sp)-2 aresult of the "trapping" of the chainbetween tpy domains.[2] 1 2 i R -N=C=N-R NR2 3,5-Me2-Pz Pr : (R,Sp)-3 Fe Fe H 3,5-Me2-Pz Cy : (R,Sp)-4 PPh iPr : (R,R )-5 We nowdescribe the extension of these observations to new typesof 2 p bis(2,2':6',2"-terpyridine) ligands and report the spectroscopic characterisa- PPh2 Cy : (R,Rp)-6 tion of atropisomeric complexes of theseligands and and the investigation Ligands 1-6 were testedinthe Pd-catalyzed allylicalkylation and amination of thedynamic processes interconverting the enantiomers. reaction using the model substrate 3-acetoxy-1,3-diphenylprop-1-ene(7)in the presence of 4mol-%Pdgiving in the case of the P^N ligands 5 and 6 full conversion andupto98% ee showing high catalyticactivities. X-ray and2D-NMR studies of Pd(π-allyl) complexes containing ligands 1-6 [1] 2,2':6',2"-Terpyridines from chemical obscuritytocommon supra- will also be presented. molecular motifs,Constable, E.C. Chem.Soc. Rev. 2007, 36, 246-253. [2] Metal-directed assembly of aconformationally restrictedmetalloma- crocycle Chow, H.S.; Constable, E.C. and Housecroft, C.E. Dalton Trans. 2003,4568-4569. [1] M.P. Coles, DaltonTrans. 2006,985. [2] a) F.T. Edelmann, Coord. Chem. Rev. 1994, 137,403. b) J. Barker, M. Kilner, Coord.Chem.Rev. 1994, 133,219.

Inorganic and Coordination Chemistry 175 Inorganic and Coordination Chemistry 176

NewSynthetic Strategies towards Oxidic Materials Aryloxide clusters of (transition metal ions in analogy to) alkali andalkaline earthmetal ions Franziska Conrad, Greta R. Patzke AurélienCrochet,Katharina M. Fromm* Institute of InorganicChemistry, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland University of Fribourg, Ch. du musée9 CH-1700 Fribourg,Switzerland Functional oxide-basednanomaterials are essential components of modern materials chemistry. Therefore, we focus on the synthesis and characterisa- Theregain in interestofalkali alkoxides and aryloxides resides in the dis- tion of ternaryoxides, such as ZnGa2O4.Based on an almost ideal spinel covery of high-temperature superconducting compoundswhich has generat- structure, zinc gallate is atransparent and conductive oxide that emits blue ed agreatinterestinthe formation of oxidematerialsand other ceramics. light[1] and is well known to be agoodlow-voltagephosphor material[2].In [3] However the structures of these compoundsare mainly based on the differ- order to facilitate thesynthesis of nanostructuredtransition metal oxides , ence of electronegativity between the metal and the oxygen atom (interac- we develop microwave-hydrothermal techniques as ahighly efficient and tion M-O) associated with the bulkinessofthe Rgroup.[1-4] Somerelevant time-saving pathway. This technique mayreplace standard hydrothermal examples as afunction of the metal ion and ligand size, as well as neutral O- methods due to better crystallisation kinetics. At the moment, we are per- donorligandswill be presented. forming methodological studies on doped zinc gallium spinels that offer important options for the construction of new display types.The morphol- ogy and chemical composition of hydrothermal and microwave-assisted synthesizedZnGa2O4 spinel particleswere investigatedwith respect to the influenceofpH, reaction temperature, timeand metal ratio of the starting O material. Cr Furthermore, we also apply the above-mentioned methodology on the syn- Li thesis of novel(Nb, M)Ox (M =Mo, W) oxides. They combine promising catalytic properties with interesting structural chemistry features, and their nanoscale synthesisstill remains achallengingtask. Especially the(Nb, Mo)Ox system is currently underinvestigation with respect to the micro- wave-assisted synthesis of novel phases. [1]W.Maudez, M. Meuwly, K. M. Fromm, Chem. Eur.J., 2007,13, 29, [1] M. Hirano, M. Imai, M. Inagaki, J. Am.Ceram. Soc. 2000, 84,977. 8302-8316 [2] M. Hirano, N. Sakaida, J. Am. Ceram. Soc. 2002, 85,1145. [2] K. M. Fromm, E. D. Gueneau, A. Y. Robin, W. Maudez, J. Sague, R. [3] R. Kiebach, N. Pienack, W. Bensch, J.-D. Grunwaldt, A. Michailovski, Bergougnant, Z. Anorg. Allg.Chem. 2005, 631,1725-1740 A. Baiker, T. Fox, Y. Zhou, G. R. Patzke, Chem. Mater. 2008, 20, [3] K. M. Fromm, Dalton Trans.,2006, 43,5103-5112 3022. [4] W. Maudez, D. Häussinger, K. M. Fromm, Z. Anorg. Allg. Chem.,2006, 632,2295-2298 INORGANIC AND COORDINATION CHEMISTRY660202 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 177 Inorganic and Coordination Chemistry 178

Mean Field study of induced magnetic moment in a2d-multibandHub- Novel phthalocyanine-basedstopcock for zeolite L bardmodel. a b c Apossible approach to some main groupbinarycompounds. Le-Quyenh Dieu ,André Devaux ,Ismael López-Duarte ,M.Victoria Martínez-Díazc,Dominik Brühwiler*a,Gion Calzaferrib,Tomás Torresc EduardoCuervo-Reyes,ReinhardNesper a InstituteofInorganic Chemistry, University of Zürich Winterthurerstrasse 190, 8057 Zürich, Switzerland Lab. für Anorganische Chemie/ETH-Hönggerberg, Wolfgang Pauli St. 10, b CH-8093,Zürich ,Schweiz DepartmentofChemistry and Biochemistry, University of Bern Freiestrasse3,3012 Bern, Switzerland c We set apossible 2-dHubbard Hamiltonianincluding an itinerant p-band Departamento de Química Orgánica,Universidad AutónomadeMadrid hybridized with localized orbitals. Inspired in recent studies of magnetism in Cantoblanco 28049 Madrid, Spain compounds with no transitionmetal, we look at the magnetic moment in- The one-dimensional channel system of zeolite Loffers possibilities to ob- duced by external field. Our model is solved in the Mean field approxima- tain defined arrangements of monomericdyes, resulting in efficientenergy tion and several thermodynamic quantities are computed. We obtain avarie- transfer materials.Communication with external objects is established by ty of behaviors stronglydependent on thefine tuning of the accounted inte- functionalization of the channel entrances of the zeolite crystals with fluo- ractions. rescent stopcock molecules. We report the first phthalocyanine-based stop- cock for selectiveadsorption to the channel entrances of zeolite Land the realisation of anew electronic dipole moment coupling situation between [1] S. Wengert, ETHDiss. 1997, Nr.12070,1. dyes in thezeolite channels and stopcock molecules [1]. Photonic antenna [2]M.Imada et al, Rev. Mod. Phys. 1998, 70,1039. systemsbased on this concept are of particular interest in the design of sen- [3]G.Kotliar et al, Rev. Mod. Phys. 2006, 78,865. sitised organic solar cells [2]. [4] G. Y. Gao et al, J. Phys. 2007, 19,315222.

[1] L.-Q. Dieu et al., Chem.Commun. 2008,1187. [2] D. Brühwiler et al., Chimia 2007, 61,820.

Inorganic and Coordination Chemistry 179 Inorganic and Coordination Chemistry 180

Insightinto fuel cell membrane degradation by pulseradiolysis Repair of Protein Radicals by Ascorbate experiments Anastasia S. Domazou,Jan Gebicki and Willem H. Koppenol S. M. Dockheer,A.Domazou, L. Gubler, G. G. Scherer,W.H.Koppenol, A. Wokaun Institute of Inorganic Chemistry, Swiss Federal Institute of Technology, CH-8093 Zürich, Switzerland, and Free Radical Biochemistry Group, De- ETH Zürich, Wolfgang-Pauli-Strasse 10, 8093 Zürich partment of Biological Sciences, MacquarieUniversity, Sydney,NSW 2109,Australia Membrane durability has becomeacentralissue forthe progress of polymer electrolyte fuel cells, PEFCs. Accordingly, understanding the mechanism of Proteinsare significant biological targetsfor partiallyreduced oxygen spe- membrane degradation is crucial to improve suitablemembrane materials. cies in vivo.The subsequentlyrandom formedradicals on the surface of Free radical species, such as the •OH and •OOH, directly producedonthe proteins yield often tryptophan and tyrosyl radicals through intramolecular platinum catalyst at the fuel cell electrodes, are assumed to considerably electron transfer. We generated theseradicals specifically by azide radicals contribute to theageing process of the polymer. In order to obtain insight in insulin,β-lactoglobulin, pepsin, chymotrypsin,and bovine serum albu- into possiblepolymer-chain-degradationmechanismsrelevant for fuel cell min. The rate constants measured varied between 108 to 109 M−1s−1,depend- applications, this work focuses on the kinetics of the •OH towards low- ingonthe protein. Theformation and disappearance of tyrosyl and trypto- molecular-weight soluble polymers of poly(styrene sulfonic acid) as model phanylradicals was followed at 405 and 510 nm, respectively. The free ty- systems. rosyl and tryptophanyl radical are knowntoreact with monohydroascorbate with rate constantsclose to 108 M−1s−1.The rate constants for reactions of protein-bound tryptophanyl radicals with monohydroascorbate in chymo- trypsinand pepsin arequite similar, while that of β-lactoglobulin is smaller by afactorof5.The corresponding rate constant values for protein-bound tyrosyl radicals are ca. 30 − 40 %ofthat of the free tyrosyl radical, with the exception of that of β-lactoglobulin, whichissmaller by afactor of 400. Theseresults aresimilar to those obtained with lysozymebyothers. Pre- viously, we foundthat glutathionereduces the tryptophanylradical in lyso- zymewith arate constant of 105 M−1s−1 [1]. Although monohydroascorbate is present in cellsin10-fold smaller concentrations than glutathione, it ap- pears to be more importantfor the repairofprotein radicals. The results suggest that the loss of ascorbate in living organismssubjected to oxidative stress mayresult from repair of protein radicals.

[1] T. Nauser, W. H. Koppenol, and J. M. Gebicki, Biochem. J. 2005, 392, 693. INORGANIC AND COORDINATION CHEMISTRY660303 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 181 Inorganic and Coordination Chemistry 182

Rhenium-Catalyzed Ethanolysis of Borane-Amine and Its Use in New insights into the structure and properties of Musa acuminata MT3 Transfer-Hydrogenation of Terminal Olefins H.-L. Dong,H.Berke* AugustoC.S.Cabral,Eva Freisinger InstituteofInorganic Chemistry, University of Zurich Institute of Inorganic Chemistry, University of Zürich, Winterthurerstrasse Winterthurerstrasse 190, CH-8057 Zurich, Switzerland 190, 8057 Zürich, Switzerland Borane-amineadducts are widely encountered in modern synthetic organic Metallothioneins (MTs)constitute afamily of proteins present in allanimal chemistry and industrial processes. Their applications include aqueousre- phyla examined so far as well as in certain fungi, plants andcyanobacteria. ductions of aldehydes and ketones, reductive aminations, olefin hydrobora- MTs are generallysmall proteins(<10kDa)featuring ahighpercentage of tions and amide reductions. Borane-amineadducts are relatively stable, even cysteine thiolate groups and alarge metal ion content [1]. Their function is at 50oC, in ethanol and water maybe due to the high energy barrier of the notfinally resolved yet, but has been related to protection against metal ion reactions. It was found that water-soluble complex toxicity,regulation of physiologicalrelevantmetal ions (ZnII andCuI)and [ReBr (NO)(CH CN)(PTA) ]can activate the ethanolic and hydrolic clea- 2 3 2 protectionagainst oxidative stress. vage of stable borane-amine complexes undermild conditions. M. acuminata (banana)MT3 belongstothe plantMTfruit-specific p3 sub- family. It contains atotal of 65 amino acids, among them 10 cys and 1his Amine+ B(OR ) +3H 1 3 2 residues. The ability of MT3and itsH46C-MT3mutant to bind up to four Ethanolysis divalent metal ions has been alreadydescribed, and apparent pKa values of cat. [Re] the cys residues havebeen determined [2]. Amine-BH3 Alcohol In thepresentwork, we will evaluate the metal ion binding abilities of the apo-proteins with UV and CD spectroscopy. Limited proteolytic digestion R experiments give insights into themetal-thiolate clusterorganization in the Amine +B(OR1)3 + R protein, and results are corroborated by measurements performed with dy- Transfer-Hydrogenation namic light scattering. Isothermal titration calorimetry studies of both, MT3 and the H46C-MT3 mutant, to accessthe cluster stability will be presented - - i - anddiscussed as well. R1=MeO ,EtO and PrO

References: Support from the Swiss National Science Foundation (SNF grant 20- [1]Couturier,M.; Tucker,L.J.; Andresen, M. B.; Dube, P.; Negri, T. J. 113728/1 and SNF- Förderungsprofessor PP002-119106/1 to E.F.) is grate- Org.Lett., 2001,3,465. fully acknowledged. [2] Couturier, M.; Tucker, L. J.; Andresen, M. B.;Dube, P.;Brenek, J. S., Negri, T. J. Tetrahedron Lett., 2001,42, 2285. [1] M. Capdevila, P. González-Duarte,in: J. A. McCleverty, T. J. Meyer (Eds.), Comprehensive Coordination Chemistry II,2004, 8,213. [2] E. Freisinger, Inorg. Chim. Acta 2007, 360,369.

Inorganic and Coordination Chemistry 183 Inorganic and Coordination Chemistry 184

Photophysical properties of pyridyl fuctionalised 2,2':6'2''-terpyridine BimetallicLanthanide Complexes for Anion Sensing ruthenium(II) complexes. Badr El Aroussi,Gérald Bernardinelliand JosefHamacek* Jonathon E. Beves, Edwin C. Consable, Emma L. Dunphy and Catherine E. Housecroft Department of Inorganic, Analytical andApplied Chemistry, University of Geneva, 30 quai E.-Ansermet, CH-1211Geneva4 Department of Chemistry, University of Basel, Spitalstrasse 51, 4056 Basel Tripodal[1] ligands areparticularly The optical properties 4-(4'-pyridyl)-2',2':6',2''-terpyridine metal complex- interestingfor improvingluminescent es are of interest in supramolecularchemistry due to the change in absorp- detectionofanalytes in Vis and IR. In tion and emission that occurs with differing protonation states. [1-2] this context, ligand L representsa new asymmetric receptorbearing two tridentate dicarbonylpyridine andone H Me N N N bidentate carbonylpyridine units anc- hored on the tertiary carbon.This ligandissupposed to provide acavity for eight-coordinated lanthanide ca- N N N tion. Leaving one free position for N N N N N N interactingwith an anionic analyte. 1 2 3 However, theX-raycrystal structure of the europium complex ([M]/[L] = 1:1) revealed adimeric forminthe solidstate. Thedimeric structurewas Here we describe the photophysical propertiesofarecentlyreported [3] confirmedinsolution by means of spectrophotometry, ES-MS and lumines- series of bis{4'-(n-pyridyl)-2',2':6',2''-terpyridine}, (where n=2,3,4), ru- cence. Introduction of bidentate anions (i.e.acetates) with the complex in thenium(II) complexes and their protonated and methylated analogues ex- acetonitrile solution resultsindrastic changes of its photo-physical proper- emplifiedbythe ligands 1-3. ties.

[1] (a) M. Seitz, M. D. Pluth,and K. N. Raymond, Inorg. Chem. 2007, 46, [1] E. C. Constable, C. E. Housecroft, A. Cargill Thompson, P. Passaniti, 351. (b) J.-M. Senegas, G. Bernardinelli, D. Imbert, J.-C.G.Bünzli, P.-Y. S. Silvi, M. Maestri, and A. Credi, Inorg. Chim. Acta., 2007, 360,1102. Morgantini,J.Weber, andC.Piguet, Inorg. Chem. 2003, 42,4680. [2] C. Zhang, H. Huang, B. Liu, M. Chen and D. Qian, J. Lumin., 2008, 128,469 [3] J. E. Beves, E. L. Dunphy, E. C. Constable, C. E. Housecroft, C. J. Ke- pert, M. Neuburger, D. J. Price and S. Schaffner, Dalton Trans., 2008, 3,386 INORGANIC AND COORDINATIONCHEMISTRY660404 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 185 Inorganic and Coordination Chemistry 186

Chargeand energy transfer through salt bridges Enhanced Spin Crossover through Self-Organization of Iron Complexes

JonathanC.Freys,GéraldBernardinelli, OliverS.Wenger* Claudio Gandolfi,a Grace G. Morgan,b Martin Albrecht*,a

Department of Inorganic,Analyticaland AppliedChemistry, and Laborato- a UniversityofFribourg, Ch. du Musée 9, CH-1700 Fribourg, Switzerland ry of X-ray Crystallography, University of Geneva, 30 quai Ernest- b UniversityCollege Dublin, Belfield, Dublin 4, Ireland Ansermet, 1211 Geneva4,Switzerland. Cooperativespin-crossover systemsthat show bistability and thermal hys- teresis areattractive components for fabricatingoptical and magnetic mem- Photoinduced charge and energy transfers play important roles in many bio- orydevices[1].Weaim at self-assembling switchable amphiphilic mole- energetic conversion mechanisms. In this greater context,westudy cationic culesinorder to promote cooperative effectsbetween the metal centers. metal complexes with 2,2’-biimidazole ligands that can form salt-bridges This approachisexpectedtoeventually amplifythe response towards exter- with carboxylates: nal stimuli. + N HN O R self-assembly Fe HN O R N

1 R=H

2 R=O n S=5/2 S=1/2 (purple) ΔT (blue) We have introduced apolar groups in complex 1,which is known for its thermochromic properties due to agradual spin transition [2]. The resulting complexes 2 areamphiphilic and therefore self-organize spontaneously at interfacesand in solution. We will present evidence for the formation of self-assembled monolayers and sphericalparticles. Remarkably, the spin- crossover activity of themetal centers is considerably amplified as aconse- quence of such spontaneousorganization.

Two case studies will be reported:Aniridium(III) complex that is useful for [1] O. Kahn, C.J. Martinez, Science 1998, 279,44. C. Saioa, M. Gábor, proton coupledelectron transfer investigations, and aruthenium(II) complex J.A. Real, A. Bousseksou, Angew. Chem. Int. Ed. 2006, 45,5786. E. that transfers energy to an anthracene moiety across the hydrogen bonds. Coronado et al., Adv. Mater. 2007, 19,1359. [2] M.F. Tweedle, L.J. Wilson, J. Am. Chem. Soc. 1976, 98,4824.

Inorganic and Coordination Chemistry 187 Inorganic and Coordination Chemistry 188

ACC-Oxidase model complexes, apossible Cu(I)-OOHintermediate. Water-soluble arene ruthenium complexes containing pyridinethiolato ligands:Synthesis,molecular structure,redox properties and anti- 6 2+ W. Ghattas,M.Gorgie, Y. Hitomi, J. Simaan, M. Réglier cancer activityofthe cations[(η -arene)Ru(p-SC5H4NH)3]

Université Paul Cézanne Michaël Gras a,Bruno Therrien a,Georg Süss-Fink a,* Biosciences FRE CNRS 3005 Facultédes SciencesetTechniques, Saint Jérôme a Institut de Chimie, Université de Neuchâtel, Case postale 158, 13397 Marseille Cedex 20 ,France CH-2009 Neuchâtel, Switzerland

Ethylene is aplant hormone that regulates many stages of aplant life, like 6 2+ The synthesis of the complexes [(η -arene)Ru(SC5H4NH)3] ,obtained from germination, fruitripening and leaf colorchange. Thelast step of the bio- the reaction of 4-pyridinethiolwith the corresponding precursor (η6- synthesis of ethyleneiscatalyzed by ACC-Oxidase, anon-hemeiron con- arene)2Ru2Cl4,isreported. The reaction involves atransfer of ahydrogen taining enzymethat utilizes oxygen to oxidize 1-aminocyclopropanecar- atom from sulfur to nitrogen in the three ligands coordinated to ruthenium. boxylic acid (ACC) into ethylene (Figure 1).

H R' 2+ H COO- 2e-+2H+ R'

+ O2 H2CCH2+CO2 + HCN +2H2O Ru + ACCO-Fe(II) Cl HS N Ru H NH3 Cl Cl S S H ACC Cl S Ru N Figure 1: Oxidation of ACC into ethylene by ACC-Oxidase. H N R' N H Many questions about the enzymatic oxidation mechanismand the role of H the metallic ion remain unanswered. Nevertheless, it is accepted that the R' first step of the reaction is the fixation of ACCand dioxygen on theFe(II) =

center. Therefore we were interested in studying the coordination of ACC 1324 on metal cations [1]. We succeeded in preparing and characterizingseveral iron andcopper ACC The molecular structure of these complexes, isolated as thechloride salts, complexes. Reacting these complexes with H2O2 generatesethylene [2]. their redox properties and their anticancer activities will be presented. Surprisingly during this oxidation reaction areduced Cu(I) intermediate was observed andcharacterized at low temperature [3].

[1] W. Ghattas, C. Gaudin, M. Giorgi, Chem.Commun. 2006,1027 [2] W. Ghattas, M. Giorgi, C. Gaudin, BCA, 2007,43424 [3] W. Ghattas, M. Giorgi, Y. Mekmouche, Inorg. Chem. 2008,ASAP. INORGANIC AND COORDINATION CHEMISTRY660505 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 189 Inorganic and Coordination Chemistry 190 Ruthenium(IV)-Catalyzed Allylation of Indoles andRelated Scanning Tunnelling Microscopy examinationofmonolayers of den- Ruthenium(IV) Organometallic Complexes dritic complexesof2-Pyridinecarboxaldehyde-2’-pyridylhydrazone

Stefan Gruber, Alexey B. Zaitsev, Paul S. Pregosin, Constable EdwinC., Housecroft Catherine E., Häusler Marc ETH Hönggerberg, Wolfgang-Pauli-Str.10, CH-8093 Zürich, Switzerland University of Basel, Department of Chemistry, Spitalstrasse 51, 4056 Basel, Dicationicruthenium(IV) allylcomplexes areefficient catalystsinthe Friedel- Switzerland Crafts allylation of phenols and relatedcompounds [1]. We have found that related ruthenium(IV) complexes also efficiently catalyze the reaction of indoles with allyl Hydrocarbon modified dendritic wedges areabletoformstable monolayers alcohols to form 3-allylindoles under mild conditions in high yield and selectivity on highly ordered pyrrolitic graphite.1 [2]. This process offersseveral advantages over the conventional palladium- The synthesis of these dendritic wedgesisasimple and efficient process catalyzed transformation: a) high regioselectivity with respect to the alcohol, b) thatcan be easily be done on alarge scale. very short reaction times at room temperature, and c) there is no need for additives [3]. Of special interest to our group is the attachment of metal binding ligands to (PF ) these wedges. The ligand 2-pyridinecarboxaldehyde-2’-pyridylhydrazone 6 2 4 2 5mol % R3 R R R2 R2 (paphyH) was considered to be apromising candidate. We have coupled Ru MeCN first and second generation dendritic wedges with paphyH. We obtained the 4 R MeCN free ligands of the first and second generations as well as the corresponding + 4 + R3 3 R N R OH N N iron (II) complexes. The monolayers of these compounds were studied by MeCN R1 R1 R1 using scanning tunnellingmicroscopy (STM). In order to explain the observed exclusive linear selectivityinthe reaction of dienol alcohol with indole, we studied the stoichiometric reactions of dienylacetate sub- strates with[Ru(Cp*)(CH CN) ](PF ). The structuresofthe resulting Ru(IV) η3- 3 3 6 1 Scherer, L. J.; Merz, L.; Constable, E. C.; Housecroft, C. E.; Neuburger, vinyl-allyl salts were established using NMRspectroscopy and X-ray analysis. M.; Hermann,B.A.J.Am. Chem. Soc. 2005, 127,4033-4041. (PF6) (PF6) rt,30min Ru MeCN + O Ru 98% yield OAc CH Cl MeCN 2 2 O MeCN Me

[1] I. Fernandez, R. Hermatschweiler, F. Breher, P. S. Pregosin, L. F. Vei- ros, M. J. Calhorda,Angew. Chem., Int. Ed., 2006, 45,6386. [2] A. B. Zaitsev, S. Gruber, P. S. Pregosin, Chem.Commun., 2007,4692. [3] M. Kimura, M. Futamata, R. Mukai, Y. Tamaru, J. Am. Chem. Soc., 2005, 127,4592.

Inorganic and Coordination Chemistry 191 Inorganic and Coordination Chemistry 192

Toward 3D Helicates: Self-assembly of Tetrahedral Ln(III) Complexes Cobalt Complexes of Ditopic 2,2':6',2"-Terpyridine Ligandswith FlexibleSpacers –Polymers or Metallomacrocycles? Josef Hamacek,1 G. Bernardinelli,2 Y. Filinchuk3 Edwin C. Constable*, Kate Harris,Catherine E. Housecroft*, 1Department of Inorganic, Analytical and AppliedChemistry; University of MarkusNeuburger and Silvia Schaffner Geneva, 30 quai E. Ansermet, 1211 Geneva, Switzerland 2 Laboratory of X-rayCrystallography; University of Geneva, 24 quai E. Department of Chemistry, University of Basel, Ansermet, 1211 Geneva, Switzerland Spitalstr. 51, 4056 Basel, Switzerland 3 Swiss-NorwegianBeamLines (SNBL) at theEuropean Synchrotron Ra- diation Facility (ESRF); 6rue Jules Horowitz, 38043 Grenoble, France Thereactionoftransition metal ions with ditopic ligandscontaining two Recently,the thermodynamic modelling has been applied to linear polynu- 2,2':6',2"-terpyridine metal-binding domains linked by variable spacers can clearhelicates with lanthanides in order to extract key energetic parameters give metallopolymers [1] (copolymers with alternating metal centres and forprogramming the first linear tetrametallic helicate.[1] Here we report on ligands),discrete molecular macrocycles [2], or mixtures of the two. The tetrametalliccomplexes, where 3D arrangement of trivalent lanthanides(Eu- outcomeofthe coordination dependsonthe precise reactionconditionsas Lu) is controlled throughthe self-assembly with anew tripodalligand L. X- well as the nature of both the spacer andthe transition metal ion. ray crystallographyshows,that four nine-coordinated cationsadopt aregu- lar tetrahedral arrangement, which is maintainedinsolution,asdemonstrat- We have used ditopicligands with two2,2':6',2"-terpyridine units linked by ed by NMR, ESI-MS andspectrophotometry. These remarkable highly flexible oligo(ethyleneoxy) spacerstosynthesise cobalt(II)-containing charged structures with four lanthanides in asmall volumeprovide interest- metallomacrocycles of various sizes. Their dynamic behaviour in solution ing perspectives for exploring intramolecular optical andparamagnetic has been studied using 1HNMR. Oxidationofthese products to give the communication in homo- and heterometallic edifices. cobalt(III) species allowedustoinvestigate these compounds with diffusion NMR spectroscopy, and thus to determine their relative sizes in solution.

We have isolatedneutral mono-2,2':6',2"-terpyridine complexes with labile transition metal ions. The interplay between metallomacrocycles and polymers is also dependentonthe counteranion, with the assembly of poly- mers favoured in the presence of coordinating anions.

[1] H. Hofmeier, S. Schmatloch, D. Wouters and U. S. Schubert, Mac- [1] K. Zeckert,J.Hamacek, J.-M. Senegas, N. Dalla-Favera, S. Floquet, G. romol. Chem. Phys., 2003, 204,2197-2203. Bernardinelli, C. Piguet, Angew. Chem.Int.Ed. 2005, 44 7954. b) N. [2]E.C.Constable, C. E. Housecroft,M.Neuburger, S. Schaffner and Dalla-Favera,J.Hamacek,M.Borkovec, D. Jeannerat, G. Ercolani, C. C.B. Smith, Dalton Trans., 2005,2259-2267. Piguet, Inorg. Chem. 2007, 46,9312. INORGANIC AND COORDINATION CHEMISTRY660606 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 193 Inorganic and Coordination Chemistry 194

In Vitro AnticancerActivity and Biologically-Relevant Metabolization C4-bound N-heterocyclic carbenes: of Organometallic Ruthenium Complexes with Carbohydrate-based exceptionallystrong donor ligands for catalytic bond activation Ligands Marion Heckenroth,Antonia Neels, Gunnar Garnier, Martin Albrecht* [a],[b] [a],[b] [a] ChristianG.Hartinger, Alexey A. Nazarov, Isabella Berger, Mu- University of Fribourg, Ch. du Musée 9, CH-1700Fribourg, Switzerland hammad Hanif,[a] Maxim L. Kuznetsov,[c] Michael Groessl,[a] Frederic [d] [d] [a] Schmitt, Olivier Zava, Michael A. Jakupec, Lucienne Juillerat- In the last few years, N-heterocyclic carbenes (NHCs)have emerged as ver- [d] [b] [a] Jeanneret, Paul J. Dyson, and Bernhard K. Keppler satile ligandsincatalysis [1]. Recently, abnormal C4 bondinghas been dis- covered as anew carbene bondingmode [2].Previousreactivity studies [a]Institute of Inorganic Chemistry, University of Vienna, Waehringer Str. suggestedthat C4-boundcarbenes arestronger donors than normal C2- 42,A-1090Vienna, Austria bound analogs [3]. To probe the influence of electronic factors we prepared [b]Institut desSciences et IngénierieChimiques, Ecole Polytechnique Fé- two related NHC palladium complexes 1 and 2 with identical steric envi- dérale de Lausanne (EPFL),CH-1015 Lausanne,Switzerland ronment, but containing cis chelating dicarbenesbound via C2 and C4 re- [c]Centro de Química Estrutural, Complexo I, Instituto SuperiorTécnico, spectively[4]. TU Lisbon,Av. RoviscoPais, 1049-001 Lisbon, Portugal [d] University Institute of Pathology, Centre Hospitalier Universitaire Vau- dois (CHUV), Rue du Bugnon 25, CH-1011 Lausanne, Switzerland N N N N N N N Thesynthesis and in vitro anticanceractivity of dihalogenido(μ6-p- N cymene)(3,5,6-bicyclophosphite-α-D-glucofuranoside)ruthenium(II) com- Pd Pd X X plexes are described. The compounds were characterized by NMR spectros- normal abnormal X X copy and ESI mass spectrometry, and the molecular structures of the chlori- 1 C2-bounddicarbene C4-bound 2 do, bromido and iodide complexeswere determined by X-ray diffraction analysis.The complexes were shown to undergo aquationofthe first halo- We will provide evidencethatthe electron density at the palladium centeris genido ligand in aqueous solution,followed by the hydrolysis of aP–O markedly higher in C4- than in C2-bound carbenecomplexes. These elec- bond of the phosphite ligand and finally formation of dinuclear species. The tronic properties of the ligand have consequences in catalysis, in particular hydrolysis mechanismwas confirmed by DFT calculations. The aquationof in oxidative addition and reductive elimination sequences. the complexes was markedly suppressedin100 mM NaCl solution, and not- ably only very slow hydrolysis of the P–O bond was observed. The com- [1] W.A. Herrmann, Angew. Chem. Int. Ed. 2002, 41,1290. plexes showed affinity towards albumin and transferrin and monoadduct [2] A.R. Chianese, A. Kovacevic,B.M. Zeglis, J.W.Faller, R.H. Crabt- formation with 9-ethylguanine. In vitro studies revealed that the3,5,6- ree, Organometallics 2004, 23,2461. bicyclophosphite-1,2-O-cyclohexylidene-α-D-glucofuranoside complexwas [3] M. Heckenroth,E.Kluser, A. Neels, M. Albrecht, Angew. Chem. Int. the most cytotoxiccompound in human endothelial cells and human cancer Ed. 2007, 46,6293. cell lines. [4] M. Heckenroth,A.Neels, G. Garnier, M. Albrecht, in preparation.

Inorganic and Coordination Chemistry 1951Inorganic and Coordination Chemistry 96

Copper(I) bipyridine complexes: thesensitizers of the future for DSSCs High-drivingforce dyads for charge transfer in the solid state

Takeru Bessho,a Edwin C. Constable,b Michael Graetzel,b AnaHernandez William Herzog,Akram Hijazi,Oliver S. Wenger* Redondo,a CatherineE.Housecroft,a William Kylberg,a Md. K. Nazeerud- din,b Markus Neuburgera and Silvia Schaffnera Department of Inorganic,Analyticaland AppliedChemistry,University of Geneva, 30 Quai Ernest-Ansermet, 1211 Geneva 4, Switzerland aDepartment of Chemistry, UniversityofBasel, Spitalstrasse 51, CH 4056 Basel, Switzerland; b Laboratory of Photonicsand Interfaces (LPI), Institute of Chemical Science and Engineering,Faculty of Basic Science ,Ecole Photoinduced charge separation in molecularsystemsiscommonly ob- Polytechnique Federale de Lausanne,CH-1015 Lausanne Switzerland. served in fluid solutionwhere solvent reorganizationcan stabilizethe newly formed charge-separated state. When such dyadsare takentothe solid state, Dye sensitized solarcells (DSSC) are nowadays apromising alternative to this is usuallynot possible any more and as aconsequence, electron transfer silicon-based photovoltaic devices and are underactiveinvestigation. They often shuts down. We aim to overcomethis problem with novel donor- are based on alarge surface area semiconductor, typically TiO2,and adye bridge-acceptor molecules that provideunusually high driving forces for attached to it having asmaller band gapand acting,therefore, as asensitizer photoinduced charge separation. [1]. Thesecells are inexpensive and easily prepared.

Up to now, ruthenium(II) polypyridine complexes have beenemployed as sensitizers. We now show that copper(I) complexes are surprisingly effec- tive for this application. The lower cost and higher abundance of copper versusruthenium are clearly advantageous.

In our laboratories, we have achieved efficiencies of 2.3%and we believe that iterativechemicaloptimization of ourcopper-based dyes will lead to efficiencies comparable to those where rutheniumcomplexes are employed as sensitizers [2].

[1]B.O’Regan, M. Grätzel, Nature, 1991, 353,737. Toward this end, (organic and coordination chemical) synthetic work is [2] T. Bessho, E. C. Constable, M. Graetzel, A. Hernandez Redondo, C. E. complemented by afair amount of optical spectroscopicand electrochemi- Housecroft, W. Kylberg, Md. K. Nazeeruddin,M.Neuburger and S. cal studies. Schaffner, 2008, submitted. INORGANIC AND COORDINATIONCHEMISTRY660707 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 197 Inorganic and Coordination Chemistry 198

Irreversibility of Disulfide to Thiyl Photolysis Remarkably high T1 relaxivities of the complex 3- [Ph4{Gd(DTTA)(H2O)2}3] DustinHofstetter,Thomas Nauser, WillemH.Koppenol H. Jaccard1,C.Cannizzo1,2,C.R. Mayer3,L.Moriggi1,L.Helm1 Laboratory for Inorganic Chemistry, ETH Zürich, Wolfgang Pauli Strasse 10, 8093 Zürich, Switzerland 1LCIB,ISIC,EPFL,BCH, 1015Lausanne, Switzerland 2Laboratoire de Physico-chimie des Polymères et des Milieux Dispersés, 10 Thiyl radicals are apopular target for theresearchonageing [1, 2]. Besides Rue Vauquelin,75231 Paris Cedex 05, France generation by pulse radiolysis and steady state γ-radiolyis [3, 4], photolysis 3Institut LavoisierdeVersailles, Université de Versailles Saint-Quentin, of disulfides is often used. Thereby, one assumes,that the photolysis reac- 78035 Versailles, France tion leads to aclean fission of the disulfide bond andprovides two thiyl rad- icals according to The compound 1,3,5-tris-(4- probably by -interactionsofthe DTTA-phenyl)benzene, also called phenyl groups. The objective of • Ph4DTTA3,presenting three this work is to demonstrate the RSSR +hν 2RS (1) DTTA chelators linked togetherby formation of aggregates of 3- four phenyl cycles, was designed [Ph4{Gd(DTTA)(H2O)2}3] in This reaction is assumed to be fully reversible under clean condition, i.e. if as ligand for agadolinium based water and to characterize the size there is no further reaction partner: T1 MRI contrast agent. The of these structures and the number Gd(III) complex of this compound, of moleculesinvolved. 3- 2 RS• RSSR (2) [Ph4{Gd(DTTA)(H2O)2}3] showed remarkablyhigh relaxivi- tiesfor such asmall molecule. The Analysis of this reactionbycontinuous photolysis, laser flash photolysis, NMRD profiles present an impor- HPLC and NMR techniques show, that there is aconsiderable formation of tant relaxation hump at magnetic side products. fields between 0.5 Tand 2T,indi- cating along rotational correlation time. Furthermore, the relaxivity, [1]C.Schöneich, Experimental Gerontology 1999, 34,19 defined as increase of relaxation per mmol of gadolinium, is de- [2]P.Wardman, C. vonSonntag, Methods Enzymol. 1995, 251,31 pendent on the concentration of the [3] S. Everett, C. Schöneich, J. H. Stewart,K.-D. Asmus, J. Phys.Chem. complex itself and on the concen- 1992, 96,306 tration of phosphate buffer.1 This [4]L.Grierson, K. Hildenbrant, E. Bothe, Int. J. Radiat. Biol. 1992, 62, behaviour suggests the formation 265 of intermolecular structures,

[1] S. Laus, B. Sitharaman, E. Tóth, R.D. Bolskar, L. Helm, S. Asokan, M.S. Wong, L.J. Wilson, A.E. Merbach, J. Am. Chem. Soc. 2005, 30,9368.

Inorganic and Coordination Chemistry 199 Inorganic and Coordination Chemistry 200

Anovel donor-acceptor dyad incorporating TTF and perylene- ThermotropicMesophases in Lanthanidomesogens: tetracarboxydiimide units From Dimeric Cohesion to Rational Organization

Michael Jaggi,Shi-Xia Liu, Silvio Decurtins Thomas B. Jensen,a Emmanuel Terazzi,a Bertrand Donnio,b Daniel Guillon,b and Claude Pigueta Departement für Chemie und Biochemie Universität Bern, Freiestrasse 3, CH-3012 Bern,Switzerland aDepartmentofInorganic, Analytical andApplied Chemistry, Universityof Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4(Switzerland). bGroupe des Matériaux Organiques, Institut de Physique et Chimie des Matériaux de Perylene-tetracarboxydiimides (PDIs) aremost fascinating molecular elec- Strasbourg-IPCMS,23rue du Loess,B.P. 43, F67034 StrasbourgCedex 2 tron-accepting materials due to theirchemical, thermal and photophysical (France). stability, their strong absorptioninthe visible and their strong inherent lu- minescence. The idea to fuse PDI as an acceptorwith TTF as the donor unit The tridendate dendrimer ligands L and Me4L form complexes with lantha- to form donor-acceptor (D-A)ensembles is not from far and several publica- nidesofformula [Ln(L/Me4L)(NO3)3]. The[Ln(L/Me4L)(NO3)3]
tions on this topic exist. However,sofar TTF and PDI units have been [Ln(L/Me4L)(NO3)3]2 dimerization process has been studied in CD2Cl2 so- combined using linkers and spacers, which is disadvantageous to intramole- lution by variable temperature 1HNMR and thermodynamic parameters cular charge-transfer processes [1-3]. In the work at hand, the PDI and TTF have been determined.Itisshown that the methyl groups in Me4L disfavour moieties will be fuseddirectly, constituting aD-A system expected to show the formation of dimeric complexes. arange of charge-transferoptions upon photoexcitation, oxidationand re- X COO(CH ) O COO CN duction. Chemical and electronic behaviourand material properties of the 2 10 N N N R= OOC COO(CH ) OCOO target structure promise to be tunable (R1 to R6). 2 10 N N

COO(CH2)10O COO CN Eu(NO3)3 R R R2 R3 X=H L X=Me Me4L X O N S S R6 Resultsobtainedfromsolution studies are used to rationalize measurements (DSC,POM,SAXS) carriedout on solid state samples. Complexes with L R1 N N S S R6 formsmectic phases over large temperature ranges with clearingtempera-

tures (SmA→I) around 186-200 °C. For the Me4L complexes, the clearing O O temperaturesare lower (144 -159 °C) and nematic phases are observed in a R4 R5 narrow (5 –14°C) temperature domain. In line with the thermodynamic results collected in solution, the evolutionoflayered (SmA) organization toward nematic arrangements reflectsthe decreasing intermolecular interac- [1] X. Guo et Al., Tetrahedron 2003, 59,4843. tions brought by the peripheral methyl groups. [2] H. Manikowski, D. Wróbel, K. Lewandowska, A. Graja, Synth. Met. 2007, 157,363. [1] T. B. Jensen,E.Terazzi, B. Donnio, D. Guillon, C. Piguet Chem.Com- [3] S. Leroy-Lhez et Al., J. Org. Chem. 2005, 70,6313. mun., 2008,181-183. INORGANIC AND COORDINATION CHEMISTRY660808 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 201 Inorganic and Coordination Chemistry 202

Inorganic anionsensor based on redox-active TTF derivatives Copper-based MOF for the FacileRing-Opening of Epoxides

Hong-Peng Jia, Shi-XiaLiu, Silvio Decurtins Dongmei Jiang,Tamas Mallat, Alfons Baiker*

Departement für Chemieund Biochemie,Universität Bern, Freiestrasse 3, Institutefor Chemical and Bioengineering, Department of Chemistry and CH-3012 Bern, Switzerland AppliedBiosciences,ETH Zurich, Hönggerberg,HCI, CH-8093 Zürich, Switzerland

Inorganicanions play an important role in awide range of industrial, envi- Metal-organicframeworks (MOFs) have generated great interest in the past ronmental and medicinal processes.[1,2] Numerous efforts have been devoted decade as newpromising materials for gas storage, separation, and hetero- to the development of sensors to achieve high selectivity andsensitivityof geneous catalysis. Herein, we developed asimplified andfacile route for the anions. The common strategy is to introduce the functionalgroups, such as synthesis of the flexible Cu-MOF [1] (Figure 1) from Cu(BF4)2 and pyrrole, imidazolium,amide, etc.,which can form hydrogen bonds with 4,4´-bipyridine in aqueousethanol. Thecrystalline Cu-MOF is ahighly ac- anions.[2,3] Herein, we describe the synthesis and properties of someelec- tive and selective Lewis acid catalyst in the ring-opening reactions of epox- tro-optical sensors(Scheme 1), comprising achromophore and aredox-active ides with alcohols and aniline under ambient, solvent-free conditions at room TTF (tetrathiafulvalene)unit to generate strongcolorimetricand electro- temperature (Figure 2) [2]. The catalystCu-MOF wasfound trulyheteroge- chemical signals. neousand recyclable without any loss of activity. N N Scheme 1 A- F F chromophore anion H B F F TTF high selectivity forA- N N NF H O R O OH H O F N B F 3 F Cu H N N H O F N N F O Cu H TTF F B N F O UV H B N R OH Redox-activegroup F H R1 R2 3 R1 R2 r.t. up to 95%yield chromophore oxidation F Cu-MOF Hydrogen-bond donor H F F - - N B F A B N N O F F H N B r.t. OH H H Cu N N O F F F O H H Cu N F B F N F O H N N aniline or or others H F B F N TTF chromophore anion F H O F UV UV 45% yield Increasedsensitivityfor A- or high selectivityfor B- ...... N N [1]T.Ghosh, B.G. Maiya, J. Phys.Chem. A 2004, 108,11249. Figure 1. Figure2. [2] N.J. Singh, E.J. Jun, K. Chellappan, D. Thangadurai, R.P. Chandran, I.-C. Hwang,J.Yoon,K.S. Kim, Org. Lett. 2007, 9,485. [1] A.J. Blake, S.J. Hill, P. Hubberstey, W.S. Li, J. Chem. Soc.-Dalton Trans. [3] P. Anzenbacher, Jr., M.A. Palacios, K. Jursíková, M. Marquez, Org. Lett. 1997,1111. 2005, 7,5027. [2] D.M. Jiang, T. Mallat, F. Krumeich, A. Baiker, J. Catal. (submitted)

Inorganic and Coordination Chemistry 203 Inorganic and Coordination Chemistry 204

NMRInvestigation of an Oligonucleotide Containing Synthesis and characterization of mesoporousoxides Metal-Mediated Base Pairs Christiane Kartusch andJeroen A. van Bokhoven Silke Johannsen1, Dominik Böhme2,JensMüller2,Roland K. O. Sigel1 ETHZürich,Wolfgang-Pauli-Strasse 10, 8093 Zürich,Schweiz 1Institute of Inorganic Chemistry, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland; In the past, heterogeneous catalysts were optimized based on their activity. 2Faculty of Chemistry, Dortmund University of Technology, Modern catalysts have to be both very active and selective to reduce their Otto-Hahn-Strasse 6, 44227 Dortmund, Germany environmental impact and to design new and better catalysts, the structure- Metal-modified oligonucleotidesare excellent candidates as molecular performance relationshipshave to be known. Because of the heterogeneity building blocks in the bottom-upapproach for nanodevices according to of the catalyst structures, however,detailed analysis and understanding are their self-assembly properties and their repetitive and well-defined structural often not possible. In supported metal catalysts in particular the effect of the features. Thus, modified nucleobases areapowerful tool to insert and sub- oxide support remains disputed.Generally, the structure of oxidesupportsis sequently array metal ions in apredictable manner into DNA. Such precise ill-defined [1]. Goal of this work is therefore to synthesize oxide supports control will be necessary for potential applications as nanomagnets, as self- that have very well-defined structures and investigate their role and structure assembling molecular wires or as catalysts in chemical reactions. under catalytically relevant conditions. Atomic layer deposition [2] is ap- Here a17ntlong oligonucleotide wassynthesized containing three imida- plied to provide mono- and multi- surface layers of different metal oxides zole (Im)moieties as nucleobasesurrogates.Melting temperature analysis such as alumina, titania and zinc oxide, on abackbone of regular, preformed suggests astructureconversion from hairpin to double helix upon addition mesoporous silicas such as SBA-15. Comparedtoconventionally synthe- of Ag(I)ionsindicating that Im-Ag+-Im basepairs were formed.[1] For a sized supports, thesesupports exhibit major advantages. Their regular me- detailed understanding of rearrangementofthe oligonucleotide in presence soporous structure,which is determined by the silica backbone guarantees of Ag(I) ions and for further characterization of the metal-mediated base optimal diffusion properties. The high surface areas allow thedeposition of pair,several NMR measurements were performed, leadingtothe three- larger amountsofactivemetal on aper gram basis. Becauseofthe presence dimensional structuresofthe hairpin and the duplex. Determinationofthe of the metal oxide as asurface layer, only spectroscopic techniques like in hydrodynamic radiiusing DLS (Dynamic Light Scattering) and DOSY situ x-ray absorption spectroscopy can be applied, which only gives limited (NMR) experiments confirm the hairpin structure in absence, and according- information about the surface of bulk metal oxides. The mesoporous oxides ly the duplexformation in presence of Ag(I) ions. will be used as support for metal catalysts and their role in chemoselective Financial supportbythe European ERAnet-Chemistry, the Swiss National hydrogenation with selected substrates will be investigated. Science Foundation(20EC21-112708 and SNF-Förderungsprofessur PP002-114759 to R.K.O.S.) and the DFG (JM1750/2-1 and EmmyNoether [1] M. K. Oudenhuijzen, J. A. van Bokhoven, D. E. Ramaker, D. C. programmeJM1750/1-3, J.M.) is gratefully acknowledged. Koningsberger, J. Phys. Chem. B, 2004, 108, 20247. [2] M. J. Biercuk,D.J.Monsma, C. M. Marcus, J. S. Becker, R. G. [1] J. Müller D. Böhme, P. Lax, M. Morell Cerdà, M. Roitzsch, Chem. Gordon, Appl.Phys. Lett., 2003, 83,2405. Eur. J. 2005, 11,6246-6253. INORGANIC AND COORDINATION CHEMISTRY660909 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 205 Inorganic and Coordination Chemistry 206

PeroxynitrateFormation During PeroxynitriteDecomposition NO autoxidation in aqueous solution studied by electron spin resonance spectroscopy Reinhard Kissner,Deepali Gupta and Willem H. Koppenol Hongping Zhu,Reinhard Kissner and Willem H. Koppenol Laboratory of Inorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Str. 10, CH-8093 Zurich, Switzerland LaboratoryofInorganic Chemistry, ETH Zurich, Wolfgang-Pauli-Str. 10, CH-8093 Zurich, Switzerland Peroxynitrous acid is an unstable peracid which is known to isomerize in a first-order reaction to nitrate with arate constant of 1.2 s−1.Akineticano- The mechanism of NO• autoxidation has been proposedvia nitric oxide di- • maly was observed together withdioxygen and nitrite formation at pH=7-8, mer (NO)2 or nitrosyldioxyl radical (ONOO ). We found evidence for • just abovethe pKa [1]. Sinceother peracids do undergo bimolecular decom- ONOO being the intermediate in the gas phase by ESR spectroscopy. position regularly [2], we suspected that such areaction could compete with Based on the gas phase result,weestimated the steady-stateconcen- the unique isomerization. An intermediate was never characterized for the tration of ONOO• to be around 10−14 Mfor the autoxidation in aqueous so- other peracids, it is thought to be too short-lived [3]. lution, of which the overall rate is also well-known. We show that aspin We were able to detect the electronicspectrum of peroxynitrate during pe- trap formsdifferent products if treatedwith afreshNO•/air mixture com- roxynitrite decomposition with aquenching method. The peroxynitrate • pared to the actionofthe final autoxidation product, NO2 .The reaction quantities formed were determined by conversion of iodide to iodine after • product with NO2 in aqueous solution does not correspond to the one ob- complete elimination of peroxynitrite. The relative yields depend on initial tained in benzene [1]. Further, we presentresults of the direct EPR detection peroxynitrite concentration, as expected for abimolecular process compet- attempt on ONOO• ing with amonomolecular one. The absolute peroxynitrate yields were more . than two times higher than expected from the radical decomposition me- chanisms favored by many biochemists [4], providing the second confirma- tion of abimolecular interaction. Finally, we could satisfactorily simulate a the kinetic anomalies observed earlier. b [1] R. Kissner, T. Nauser, P. Bugnon, P.G. Lye and W.H. Koppenol, Chem. Res. Toxicol., 1997, 10,1285. c [2] J.F. Goodman, P. Robson and E.R. Wilson, Trans. Faraday Soc., 1962, 1846. 343 345 347 349 351 [3] D.F. Evans and M.W. Upton, J. Chem. Soc. Dalton Trans., 1985,1151. B/mT [4] G. Merényi and J. Lind, Chem. Res. Toxicol., 1998, 11,243. EPR spectra of 20 mM 5,5-Dimethylpyrroline-N-oxide exposed for 1hto • • NO /air (a), air (b) and NO2 /air (c). 100 mM acetate buffer,pH=5.

[1] P. Astolfi, L. Greci, M. Panagiotaki, Free Rad. Res., 2005, 39,137.

Inorganic and Coordination Chemistry 207 Inorganic and Coordination Chemistry 208

Modified Metal-Organic Frameworks –Synthesis, Properties Gold(I)phosphine derivatives of 4,4’-dialkynylsubstituted and Potential in Catalysis 2,2’-bipyridine

Wolfgang Kleist,Marek Maciejewski, Fabian Jutz, Alfons Baiker MarzenaKocik,Edwin Constable, CatherineHousecroft

ETH Zurich, Wolfgang-Pauli-Str. 10, CH-8093 Zurich, Switzerland University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland

Gold(I)phosphine derivatives have the potential to be luminescent and have Due to their microporous structure, metal-organic frameworks have become interestingopticalproperties [1].Ligand 1 canbesynthesized from an interesting and promising class of materials for applications in heteroge- 4,4’-dialkynyl substituted 2,2’-bipyridineand triphenylphosphine gold(I) neous catalysis.[1] Based on MOF-5 and the corresponding IRMOF series[2], chloride.This compound had been structurally characterized, and related we present new methodologies for the modification of metal-organic compounds will also be described andtheir absorptionand emissive proper- frameworks with functional groups and active metal centers. ties discussed.Weplan to complex this ligand with transition metals like ruthenium(II)and iron(II)inordertoinvestigate theeffects of coordination on their electronicspectroscopic properties.

(Ph)3P Au In general, such modification of MOFs with catalytically activegroups strongly influences the physical and chemicalproperties. Therefore special attention is given to the characterization of the resulting catalyst materials N under catalytic conditions. The studiesincludeinvestigations on the thermalstability of such materials N under inert and oxidizing atmosphere as well as the stability in common 1 solvents and supercritical CO2.Basedonthese results, we were able to dis- close the scope and limitations of our materials for possible catalytic appli- Au cations. The modified materials could be utilized in gas-phase oxidation P(Ph)3 reactions as well as in catalytic processes in supercritical CO2.

[1] U. Mueller, M. Schubert, F. Teich, H. Puetter, K. Schierle-Arndt, J. Mater. Chem. 2006, 16,626. [2] M. Eddaoudi, J. Kim, N. Rosi, D. Vodak, J. Wachter, M. O’Keeffe, [1] M.Bardaji, A.Laguna,J.Vicente, P.G.Jones, Inorg. Chem., O.M. Yaghi, Science 2002, 295,469. 2001, 40,2675 INORGANIC AND COORDINATION CHEMISTRY661010 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 209 Inorganic and Coordination Chemistry 210

3+ Outersphere Coordination of [Co(NH3)6] to Domain 6ofaGroup II NovelReO3-related aluminum tungsten oxides IntronRibozyme F. Krumeich1 andG.R.Patzke2 Maximiliane M. T. Korth,Michèle C. Erat and Roland K. O. Sigel 1. Laboratory of InorganicChemistry,ETH Zurich,8093 Zurich Institute of InorganicChemistry, UniversityofZürich, Winterthurerstrasse 2. Institute of Inorganic Chemistry, University of Zurich, 8057 Zurich 190, CH-8057, Switzerland Aseriesofnew tetragonal aluminum tungsten oxides with the general for- GroupIIintronribozymes are large RNA molecules that catalyze their own mula Al4W2nO6n+2 (n =4,5,6,and 7) was foundand structurallycharacte- removal from precursor mRNA. For folding into theactivethree- rizedbyelectrondiffraction,HRTEM andHAADF-STEM [1]. Astructural dimensionalstructure, as well as for catalysis, the molecular machines re- modelfor Al4W10O32 (I4/mmm; a ≈0.375, c ≈3.95 nm)consists of slabs of quire Mg2+.[1] The 2'-OH group of ahighly conservedadenosine withindo- [5 x ∞ x ∞]corner-sharing WO6 octahedra that are connected via edge- main 6(D6), i. e. the branch point, acts as the nucleophile in the first step of sharingtoAlO6 octahedra. Simulated HRTEM images agree well with the theself splicing mechanism.The NMR solution structure of acatalytically experimental ones and therefore support theproposedstructural model. The [2] active 27 nucleotide long D6 construct(D6-27) wasrecently elucidated connection betweenadjacentslabs of WO viaAlO octahedra can be re- 2+ [3] 3 6 and its intrinsic Mg binding properties were determined. gardedasanovel variant of crystallographic shear operation for ReO -type 2+ 3 Here we investigate possible outersphere coordination of [Mg(H2O)6] in structures. Frequently, the investigated crystallites show stacking faults and the branch point region of domain 6. Cobalt(III) hexammine is commonly an intergrowth of the different phases. 2+ used as amimic for the spectroscopically silent [Mg(H2O)6] and can even show NOEcontacts with RNAprotonsinfavorable cases. Chemicalshift 3+ mapping experiments show binding of [Co(NH3)6] to the branch-point region. By performingNOESY titration experimentsinH2Oand D2Oob- serving the chemical shift changes at theRNA as well as direct NOE con- 3+ tacts between the ammineprotons of [Co(NH3)6] and RNAprotons the 3+ exact bindingpattern of [Co(NH3)6] to domain 6isbeing elucidated thereby giving information about possible outersphere coordinationof [Mg(H O) ]2+. 2 6 [1] F. Krumeich, G.R.Patzke, Microsc. Microanal. 2007, 13 Suppl. 3,366. Financialsupport by the Swiss National Science Foundation(SNF- Förderungsprofessur PP002-114759toR.K.O.S.) is gratefully acknowledged.

[1] R. K. O. Sigel, Eur. J. Inorg. Chem., 2005, 12,2281-2292. [2] M. C. Erat, O. Zerbe, T. Fox, R. K. O. Sigel, ChemBioChem, 2007, 8, 306-314. [3]M.C.Erat, Roland K. O. Sigel, Inorg. Chem., 2007, 46,11224-11234.

Inorganic and Coordination Chemistry 211 Inorganic and Coordination Chemistry 212 Electro- and Photoelectro-chemicaldepositionofThiophenemodified Hydrogen storage –continuous high pressure hydrogengeneration 2+ {Ru(terpy)2} Complexes Céline Fellay, Paul J. Dyson,GáborLaurenczy

William Kylberg,Egbert Figgemeier, Edwin C. Constable and EPFL,Institut des Sciences et Ingénierie Chimiques, Laboratoire de Chimie CatherineE.Housecroft OrganométalliqueetMédicinale, CH-1015 Lausanne, Switzerland Email: [email protected]

University of Basel, Dep, 51 Spitalstrasse,CH-4056 Basel,Switzerland Newpotential in the useofformic -The generated H2 is easily sepa- acid as ahydrogen storage material rated(the carbon dioxide can be Thienylsubstituted 2,2’:6’,2’’-terpyridinemetal complexesare known to has beendemonstrated via thede- captured andrecycled) 1 electrochemically deposit on electrodes and form polymers. Two new velopment of ahomogeneous cata- -The H generatordoes not require 2+ 2+ 2 bis-terpyridine rutheniumcomplexes (1 and 2 )were electrochemically lytic systemusing ruthenium based electricity or any particularcondi- deposited on glassy carbon electrodes and FTO (conductinglayer of trans- water soluble catalysts to selectively tions parent F-dopedSnO )glass. The complexes were also pho- 2 decompose HCOOH into H2 and -This hydrogen fuelisvery eco- to-electrochemically oxidized by adye sensitized TiO surface. Scanning 2 CO2.Continuous generation of H2 nomicand ecologic electrochemical microscopy (SECM) was used to probe someofthe redox of very high purity,over awide 2 chemistry. rangeofpressures and under mild conditionswas achieved. S S N N Main advantages O N N N Ru N O S -Noneedfor transport and storage N Ru N N N S S S O N N O of H2 gas under pressure (orlow 2+ 2 Electrochemical oxidation temperature liquid hydrogen) 2+ - + 1 -2e ,-2H Electrochemical -H generation at any wanted pres- polymerisation 2 S -2e-,-2H+ sure (from 0.5 atmtoof600 atm)

S N -H2production under mild condi- N N S * O Ru O tions (25-120°C) at very high N N N N * * N S S rate * N Ru N

O N N O S -The generated hydrogen is free

n n fromCOtraces (CO <3ppm)

[1] J. Hjelm,R.W.Handel, Hagfeldt A., Constable E. C., Housecroft C.E., Swiss National ScienceFoundation and EPFL are thanked for financial support. ForsterR.J., J. Phys. Chem. B, 2003,107, 10431-10439. [2] D. Mandler, P. R. Unwin, J. Phys. Chem. B, 2003,107, 407. [1]C.Fellay,P.J.Dyson, G. Laurenczy,International patent appl., October 2007 [2]C.Fellay,P.J.Dyson, G. Laurenczy,Angew. Chem. Int. Ed. 2008, 47, 3966 INORGANIC AND COORDINATION CHEMISTRY661111 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 213 Inorganic and Coordination Chemistry 214

Nonaqueous Sol-Gel Synthesis of Nanocrystalline Zinc Oxide Synthesis of NewPhotochromic Spin Crossover Complexes

Bettina Ludi, Markus Niederberger Peter Belser*, Karin Marxer

DepartmentofMaterials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 University of Fribourg,CheminduMusée 9, 1700 Fribourg, Switzerland Zurich, Switzerland Our group is active in the synthesis of photochromic dithienyl-containing Comingalong with the growing interest in nanomaterials as aresult of their 1,10-phenanthroline ligands. Organic dithienylethene derivatives have been unique and fascinating properties, syntheticchemist were faced with the extensively studied because of their potential applicationsinthe field of problemofdeveloping new strategies for the synthesis of monodispersed photochromic and photonic devices. Phenanthroline complexes of Iron(II) particleswith good control over the finalsize and shape. One solutioninthe on theother hand were reported to undergoatemperature dependent spin field of metal oxide nanoparticles are nonaqueous sol-gelprocesses in which crossover process.Inthis context it is highly interestingtouse photoactive amolecularprecursor is transformed into ametal oxide in an organicsol- 1,10-phenanthrolineligands to build up Iron(II)complexes. Assumingthat vent.These synthesis strategiesprovideseveral advantages,like robust syn- the photoactive opening and closing process of the ligand system changes thesis parameters and high crystallinity of the producteven at low tempera- the ligand field properties sufficiently, we should obtain asystem that un- ture and thereforebecame awell-known alternative to aqueous routes. Al- dergoes spin crossover upon irradiation with light at room temperature. This though thereaction system itselfisquitesimple, it offers agreat potential to concepthas already been studied by afew other groups and was called tailor thefinalparticle characteristicslike surfacechemistry and morpholo- ligand-drivenlight-induced spin change LD-LISC. gy [1]. In the current work we will presentthe results obtained within thesyntheses R R S S of ZnO nanoparticles, which are of great technological relevance,via non- X X aqueous sol-gel synthesis by varying the temperature and the solvent. S S N N R X R X Y- hv1 Y- N Fe Y- N Fe Y-

N N hv2 or obscurity N N

X X X X

R S S R R S S R

X=C, N,.. R=CH3,Phenyl, EWG, ERG

Figure 1: Zinc oxide nanoparticlesobtainedvia nonaqueous sol-gel synthesisina)benzyl [1] Irie, M. Chem. Rev., 2000, 100, 1685-1716. alcohol and b) tbutyl benzylalcohol [2] Kuhni, J.; Adamo, V.; Belser, P. Chimia, 2006, 60, 207-211. [3] Kolb, J. S.; Thomson, M. D.; Novosel, M.; Senechal-David, K.; Riviere, [1] M. Niederberger, G. Garnweitner, J. Buha,J.Polleux,J.Ba, N. Pinna, E.; Boillot, M.-L.; Roskos, H. G. Comptes Rendus Chimie, 2007, 10, 125- J. Sol-GelSci.Technol., 2006, 40,259. 136.

Inorganic and Coordination Chemistry 215 Inorganic and Coordination Chemistry 216

Encapsulation of Functionalised Aromatic Molecules in Hexanuclear BimetallicRedox Switches Comprising N-Heterocyclic Carbene Arene Ruthenium Cages Spacers

Johan Mattsson and Bruno Therrien László Mercs,a Antonia Neels,b Martin Albrecht*,a

Institut de Chimie, UniversitédeNeuchâtel, Case postale158, 2009 a) University of Fribourg, Ch. du Musée 9, 1700 Fribourg, Switzerland; Neuchâtel, Switzerland b) Institut de Microtechnique, Rue J. Droz 1, 2002 Neuchâtel,Switzerland.

6+ Cationictriangularmetallo-prisms,[Ru6(arene)6(tpt)2(bzq)3] ,incorporating Molecular switchesrepresent an attractiveclass of functionalentities[1]. arene ruthenium building blocks,bridged by dihydroxy-1,4-benzoquinonato Multistage switching may be accessible by connecting two transition metal (bzq) ligands, and connected by two2,4,6-tris(pyridin-4-yl)-1,3,5-triazine based activesiteswith aspacer that allowsfor acertain degree of electronic (tpt) subunits allow the permanent inclusion of large aromatic molecules communication [2]. such as pyrene, triphenylene and coronene, or the inclusion of functionalised aromatic moleculesinwhich the aromatic part is encapsulated, while the functional group is hanging out of the cage.[1] These carceplex systemscan potentiallyfindapplications in molecularrecognition, catalysis, or being used as drug delivery containers.

We will present our progress in usingbifunctional NHC ligandsasspacers in binuclear Ru(II) complexes.Specifically,wewill focus on the quality of differentcarbene spacers andspectator ligands in stabilizing mixed-valent species, which has been probed by spectroscopic and electrochemicalanaly- ses of the bimetallicsystems. Based on the electrochemical measurements, comproportionation constants (Kc)ofthe mixed-valent species have been determined. These results allow for proposing amechanism for the electron coupling process.

[1] J. Mattsson, P. Govindaswamy, J. Furrer,Y.Sei, K. Yamaguchi, G. Süss-Fink, B. Therrien, submitted. [1] W. Kaim, G. K. Lahiri, Angew. Chem. Int. Ed. 2007, 46,1778. [2] B. S. Brunschwig, C. Creutz, N. Sutin, Chem. Soc. Rev. 2002, 31,168. INORGANIC AND COORDINATION CHEMISTRY661212 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 217 Inorganic and Coordination Chemistry 218

Original Complexation of SilverIonswithAmino Acid Coordination Cages of Rhodium andIridium as Exoreceptors for Alkali MetalIons LaurentMirolo,Chen Jing and Katharina M. Fromm* SebastianMirtschin,ElviraKrasniqi, Rosario Scopelliti, Kay Severin Department of Chemistry, University of Fribourg, CheminduMusée 9, 1700-Fribourg, Switzerland Institut des SciencesetIngénierieChimiques, EcolePolytechnique FédéraledeLausanne(EPFL), CH-1015 Lausanne Amino acidscontain many oxygen and nitrogen atomsgiving multiple pos- sibilities forametalion to be coordinated. We selectedsilver which has, Hexanuclear coordinationcages of the formula [(C5Me4R)M(C7H3NO4)]6 beside itsweak coordinationrequirements both in term of coordination (M =Rh, Ir; R=Me, H) were obtained by step-wise reaction of numberand geometry, abiologicallyinterestingactivity. Itsantibacterial [(C5Me4R)MCl2]2 withfirst AgOAc and then pyridine-3,5-dicarboxylic ac- and antifungalproperties have been studied, among others, in ahistidine id. Crystallographic analyses show that the cages adopt adistorted trigon- complex previously [1].Weshow here that silver ions arecoordinatedin al anti-prismatic geometry with the pyridine-3,5-dicarboxylates function- different ways, depending on the reaction conditions.Silver ions mayfur- ingasdianionic, bridgingligands, each of which connects threedifferent thermore bind to biomolecules of various size, starting from single amino (C5Me4R)M fragments. acidstolarger peptides, forwhich theproperties were studied recently [2],or to more complex antibiotics likethe vancomycin, where the purposeistobe used as coating on implant materials [3].

The cages act as exoreceptors for the large alkali metals K+ and Cs+ but showlow affinity forNa+.Crystallographic and NMRspectroscopic ana- Fig.1: Structure of histidine and silvernitrate lysesindicate that two metal ions can be coordinated to thesurface of the cages. Therespective binding sites are comprised of three carbonyl O-atoms [1] K. Nomiya, S. Takahashi, R. Noguchi, S. Nemoto, T. Takayama&M. from the bridging pyridine-3,5-dicarboxylate ligand [1]. Oda, Inorg. Chem. 2000, 39,3301-3311. [2] Kirsten Belser, Thesis 2008. [1] S. Mirtschin, E. Krasniqi, R. Scopelliti, K. Severin, Inorg. Chem. 2008, [3] P. Brunetto &K.M.Fromm, Chimia 2008,62, 4, 249-252. in press.

Inorganic and Coordination Chemistry 219 Inorganic and Coordination Chemistry 220

PGSE NMRDiffusion and Overhauser StudiesonaVariety of Salts: an Lanthanide/ruthenium-basedmetallostar:characterization, Overview of IonPairinginDichloromethane relaxivity andluminescence

L. Moriggi1,A.Aebischer2, C. Cannizzo3,A.Sour4,J.-C. Bünzli2,L.Helm1 Aitor Moreno,Paul S. Pregosin 1 Laboratoire de Chimie Inorganique et Bioinorganique,Ecole PolytechniqueFédéraledeLausanne, ISIC,BCH,1015 Lausanne, Switzerland 2 LaboratoryofLanthanide Supramolecular Chemistry, EcolePolytechniqueFédéraledeLausanne, ISIC,BCH,1015 Lausanne, Switzerland ETH Hönggerberg, Wolfgang-Pauli-Str.10, CH-8093 Zürich, Switzerland 3 Laboratoire de Physico-chimie des Polymèresetdes Milieux Dispersés, UPMC-ESPCI-CNRS UMR7615, 10 RueVauquelin,75231 ParisCedex 05,France 4 Laboratoire de Chimie Organo-Minérale, LC3duCNRS, Institut de Chimie,UniversitéLouis Pasteur, Frequently,the nature of the anion in Transition metal salts is ignored or the 4rue Blaise Pascal, 67070, StrasbourgCedex,France anion is considered to be relatively “innocent”. However, anumberofre- Thegrowinginterestinmagnetic resonance imaging(MRI) requires thedevelopment of novel portsinthe recentliterature suggest that the choiceofthe anion can be im- multifunctional contrast agentswithhighrelaxivity(r)and possible useinother detection portant, both in termsofstructure andreactivity [1]. 1 techniques.The firstso-called Metallostar, composed of Fe(III) surroundedbythree

2- [(bipyDTTA2Gd2)(H2O)4] unitshas been synthesized andcharacterizedbyLivramentoetal. in 2005[1].Here, we presentaruthenium–based Metallostar, i.e. Cl {Ru[Ln bpy-DTTA (H O) ] }4- with Ln =Y3+,Gd3+,Eu3+,see Chart 1; characterizedbydifferent O Ru 2 2 2 4 3 Ru (PF6) P (PF6) spectroscopic techniques,withapplicationpotential as amultiimagingsystem(MRI + O N CH R CH3 luminescence). CH(CH3)(C10H7) 4- Theoptical spectroscopic properties of {Ru[Eu2bpy-DTTA2(H2O)4]3} are studied by meansof

IonPairing in CH2Cl2 UV/Vis absorption as well as steady-state andtime-resolved luminescencespectroscopy. Aqueous solutionsofthe complexdisplay sensitized europium luminescenceuponvisible excitation at 450nmofthe tris(2,2’bipyridyl)ruthenium(II) unit.

H S H H H O -OOC 4- O H - H (PF ) OOC - 6 N N (PF ) - COO 4Na+ 6 OOC N O H - N OOC - LnIII N COO H H H N O H N LNIII COO - N COO- -OOC N H -OOC N 1 19 H O III N PGSEdiffusion and H, FOverhauser studies on aVariety of Transition H Ln N O - N N II OOC Ru COO- - H N N Metal, Inorganic and Organic (PF )Salts are reported. These solution NMR -OOC N N COO- H 6 N III N Ln O H

- results show that the charge distribution and theability of the anion to ap- N COO O H N N H N COO- LnIII -OOC proach the positively charged positions are thedetermining factors in decid- -OOC N LNIII H N O N -OOC ingthe amount of Ion Pairing. H -OOC - - O - OOC COO H COO-COO H O O H [1] Pregosin, P.S; Kumar, P.G.A; Fernandez, I. Chem. Revs 2005,105, Chart1 2977.

[1]Livramento, J. B.;Toth, E.;Sour,A.; Borel, A.;Merbach,A.E.; Ruloff,R.Angew.Chem.Int.Ed., 2005,

44,1480-1484. INORGANIC AND COORDINATION CHEMISTRY661313 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 221 Inorganic and Coordination Chemistry 222 Solvent effects and organic reaction pathways CO2 capture from atmospheric air via consecutive CaO-carbonation in non-aqueous sol-gel processes and CaCO3-calcination cycles in afluidized-bed solar reactor Inga Olliges,Markus Niederberger Viktoria Nikulshina-von Zedtwitz ,Christoph Gebald ,Aldo Steinfeld Department of Materials, ETH Zurich, Wolfgang-Pauli-Strasse 10, 8093 Zurich, Switzerland ETH Zurich ,Sonneggstrasse 3, CH-8092 Zurich, Switzerland Within non-aqueous sol-gel processes [1] for the syntheses of crystalline Athermochemical cyclic process and associated reactor is proposed for the metal oxide nanoparticles, the organic component plays an important role. It continuous removal of CO2 from ambient air via consecutive CaO- not only serves as asolvent but also provides the oxygen for the oxide for- carbonation and CaCO3-calcination steps using concentrated solar energy as mation. Furthermore the organic solvent respectively the organic reaction the source of high-temperature processheat. The thermodynamics of the products strongly influence the final morphology, size, shape, crystal struc- cycle were examined and the reaction kinetics of both steps were deter- ture and assembly behavior of the particles [2]. The investigation of organic mined by thermogravimetry [1,2]. Afluidized-bed solar reactor is applied to reaction pathways can establish abetter understanding on amolecular level accomplish both steps, with reacting particles directly exposed to high-flux and therefore enables us to intentionally influence and control the particle solar irradiation. Five consecutive cycles were performed, yielding complete formation. removal of CO2 from acontinuous air flow containing 500 ppm of CO2 In the following work, we will present ashort overview of non-aqueous sol- within aresidence time of 1.3 sduring each carbonation step, and subse- gel processes. In addition the effects of several benzyl alcohol derivatives on quent complete release of CO2 and regeneration of the CaO reacting par- the syntheses of transition metal oxide particles and the influence of differ- ticles during the calcination step. ent precursors will be shown.

[1]V.Nikulshina, D. Hirsch, M. Mazzotti, A. Steinfeld. Energy 2006, 31, 1379. [2] V. Nikulshina, E. Gálvez, A. Steinfeld. Chem. Eng. J 2007, 129, 75.

Figure 1: Tungsten oxide particles synthesized in I) benzyl alcohol,II) tbutyl ben- zyl alcohol and III) fluor benzylalcohol with tungsten hexachloride as aprecursor.

[1] M. Niederberger, G. Garnweitner, Chem.Eur.J.2006, 12,7282. [2] G. Garnweitner, M. Niederberger, J.Mater. Chem. 2008, 18,1171.

Inorganic and Coordination Chemistry 223 Inorganic and Coordination Chemistry 224

Rh andIrPhosphoramiditeComplexes in Cyclopropanation New Nanocomposites with Oxidic Materials

Tina Osswald, Igor S. Mikhel, Antonio Mezzetti* Emmanuel F. C. Chimamkpam,Firasat Hussain, Greta R. Patzke

Dept. of Chemistry and Applied Biosciences, ETH Zürich, CH-8093 Zürich InstituteofInorganic Chemistry, University of Zurich, Winterthurerstrasse190, CH-8057 Zurich, Switzerland. Chiral phosphoramidite (P*) complexes have found increasing application in asymmetric catalysis. Our group has recently reported ruthenium com- The development of organic-inorganic nanocomposites is achallenging area plexes that display an η2-interaction between the metal and one aryl group of of synthetic inorganic chemistry to generate compounds with new properties the amine moiety of the binaphthol-based phosphoramidite [1]. These half- and high application potentials[1].Thus, we focus on the synthesis and cha- sandwich complexes catalyze the cyclopropanation of olefins with moderate racterization of new organic and inorganic building blocks, such as nano- efficiency [2]. Therefore, we decidedtoprepare the Rh(III) (1a)and Ir(III) structured transition metal oxides[2],polyoxometalates (POMs)[3] and poly- (1b)analogues and test them in catalysis. Chloride abstractionwith AgSbF6 mers. Recently, we have brought forward new types of lanthanide spin clus- 38- from 1a and 1b gives unstable P,C-chelate complexes. ter polyoxometalates, especially of the [Ln6As6W63O226(H2O)10] type (Ln =Eu, Gd and Tb) with interesting magnetic and structural properties:

Furthermore, we have successfully incorporated POMs into polyaniline and Upon chloride abstraction, the Rh(I) and Ir(I) analogues [RhCl(COD)(P*)] the magnetic and optoelectronic properties of the emergingnanocomposites (2a)and [IrCl(COD)(P*)] (2b)give the stable P,C-bidentatespecies 3a and are under investigation. Finally, we cross the border between natural and 3b,respectively. Preliminary tests in cyclopropanation show modest diaste- synthetic products through the combination of highly porous natural chitin reo- and enantio-selectivity: skeletons with inorganic nanoparticles.

[1] G. Kickelbick, Prog. Polym. Sci. 2003, 28,83. [2] R. Kiebach, N. Pienack, W. Bensch, J.-D. Grunwaldt, A. Michailovski, A. Baiker, T. Fox, Y. Zhou, G. R. Patzke, Chem. Mater. 2008, 20, 3022. [1] D. Huber, P. S. Pregosin, A. Mezzetti, Organometallics 2005, 24,5223. [3] A. Michailovski, H. Rüegger, D. Sheptyakov, G. R. Patzke, Inorg. [2] D. Huber, A. Mezzetti, Tetrahedron Asymmetry, 2004, 15,2193. Chem. 2006, 45,5641. INORGANIC AND COORDINATION CHEMISTRY661414 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 225 Inorganic and Coordination Chemistry 226

Mercury-Modified Ribonucleic Acids as Potential Molecular Wires Ec-1 from wheat:Ametallothionein featuring unique metal-binding domains Susann Paulusa,Silke Johannsena,Nicole Düpreb,Jens Müllerb, Roland K. O. Sigela Estevão A. Perozaa,Nancy Blüthgena,Wolfram Meyer-Klauckeb, Eva Freisingera aInstitute of Inorganic Chemistry, University of Zürich,Winterthurerstr. 190, 8057 Zürich, Switzerland; bFaculty of Chemistry, Dortmund University of aInstitute of Inorganic Chemistry, University of Zurich, Winterthurerstrasse Technology, Otto-Hahn-Strasse 6, 44227 Dortmund, Germany 190, 8057 Zürich, Switzerland bEuropean Mol. Biol.Laboratory, outstation Hamburg at Deutsches Elek- Metal-modified nucleicacids have become increasingly important as they tronen-Synchrotron, Notkestrasse 85, 22603 Hamburg, Germany provide scaffolds, which can potentially be used for molecularwires. ADNA duplex with mismatched T-T pairs can bind Hg2+ by forming Metallothioneins (MT) are small cysteine-rich proteins with high affinity for T-Hg2+-T basepairs,whichare as stableasaWatson-Crick basepair.[1] We metal ions like ZnII and CuI. Triticum aestivum (wheat) early cysteine labeled 2+ areinterested in the formation of an analogous array of Hg by using RNA protein (Ec-1) was the first MT reported in higher plants.[1]With atotal of 81 instead.[2] In vitro transcription of the required single-stranded RNA has the amino acids, including 17 Cys that are groupedinthree regionsofthe amino II potential advantage of providing high yields. We could show that T7 RNA acidsequence, Ec-1 hasbeen shown to bind six divalent metal ions (M )in polymerase can incorporate two to twenty consecutive uracil residues into two separated metal-binding domains.[2] The N-terminal domain, or RNA. In the presence of Hg2+,astructural rearrangement from hairpin to γ-domain,[3] binds two MII ions presumably via six Cys residues resulting in 2+ II regular duplex by forming Hg -mediated base pairs takes place for one of the ametal-thiolate cluster with the stoichiometry M 2Cys6,which has never sequences under investigation. This was verified by several techniques, in- been reported before for MTs. The C-terminal part of Ec-1 contains eleven cluding NMR, DLS, UV and CD spectroscopy.[2] Ongoing investigations Cys and two His residues and coordinates four MII ions. Recent work from now focus on the incorporation of continuous stretches of the chemically ourlab has focused on the study of the separateddomains of Ec-1. Results more stable thymine into RNA. For this purpose we are using the T7 RNA from variousspectroscopic investigations substantiate our previous findings polymerase mutant Y639F capable of not discriminating between de- and demonstratethe relative independence of the protein domains with re- oxy-ribose and ribose sugars.[3] Indeed we were able to construct RNAs spect to each other. In addition, we investigated the lability of the ZnII ions con-taining poly T-sequences,which are now subject to structural studies. bound to Ec-1 with amass spectrometry. Financial support by the European ERAnet-Chemistry, the Swiss National Science Foundation (20EC21-112708 and SNF-Förderungsprofessur [1] Lane, B. G., Kajioka, R. and T. D. Kennedy.Biochem. Cell Biol. 1987, PP002-114759 to R.K.O.S.) and the DFG (JM1750/2-1 and Emmy Noether 65, 1001. programmeJM1750/1-3 to J.M.) is gratefully acknowledged. [2] Peroza, E. A. and E. Freisinger, J. Biol. Inorg. Chem. 2007, 12,377 [3] Peroza, E. A., Al-Kaabi, A., Meyer-Klaucke, W., and E. Freisinger, to be [1] Y. Tanaka, S. Oda, H. Yamaguchi, Y. Kondo, C. Kojima, A. Ono, J. submitted. Am. Chem. Soc. 2007, 129 244-245. Support from the Swiss National Science Foundation is gratefully acknowl- [2] S. Johannsen, S. Paulus,N.Düpre, J. Müller, R.K.O. Sigel, J. Inorg. edged: SNF grant 200020-113728/1 and SNF Förderungsprofessur Biochem. 2008,102,1141-51. PP002-119106/1 to E.F. [3] R. Sousa, R. Padilla, EMBO J. 1995,14, 4609-21.

Inorganic and Coordination Chemistry 227 Inorganic and Coordination Chemistry 228 Synthesis and catalytic properties of palladium complexes containing Metal-Mediated Thiol-Disulfide Interconversion –ANew Tool for pyridyl and pyridylidene ligands Metallosupramolecular Chemistry

Aurélie Poulain,Antonia Neels and Martin Albrecht Edwin C. Constable, Catherine E. Housecroft, Markus Neuburger, Jason R. Price, Silvia Schaffner UniversityofFribourg, Ch. du musée 9, CH-1700 Fribourg Department of Chemistry, University of Basel, Spitalstrasse51, 4056, Palladium complexes containing an N-heterocycliccarbene (NHC) ligand Basel, Switzerland. are highly active catalystsfor cross-coupling reactions.1 Generally, the NHC ligand of these complexes is derivedfrom imidazolium salts. In thelastfew Self-replicating molecularsystems represent achallenging target for syn- years, carbene ligands derived frompyridiniumsalts (pyridylidenes) have thetic chemistry. We have recently become interested in utilising the pre- beendeveloped as newtypes of NHC ligands.2 Bercaw andcoworkers cepts of metallosupramolecular chemistry1 for the development of self- showed that such pyridylidenes are stronger σ-donors and π-acceptors than replicating systems.2 Our approach is predicated upon two phenomena: (i) classical imidazolylidene,3 which may be useful for improving the catalytic the preference of copper(II) for five-coordinate {Cu(tpy)(bpy)} environ- activity of the coordinated metalcenter. ments3 and (ii) the reversible metal-mediated reaction. We synthesized different palladium complexes containing pyridyl (1)and + - pyridylidene (2)ligands with achelating donor group Efor supporting the 2RSH →RSSR+2H +2e. metal-carbon bond and for tuning the properties of the metal center. Although thiol(thione)-disulfide interconversion has been utilisedinthe establishment of dynamic combinatorial libraries, disulfidesare less commonly encountered in metallosupramolecular chemistry. Establisment of appropriate ligand feeds has lead us to synthesise multiple polypyridyl thiones in order to fulfill redox obligations both potential and electroncount.

Presented will be the description of key thione intermediates for the pro- We will present structuralfeaturesofthese complexes in the solid state and posed self-replicating systems and describe the metal-mediated oxidation of in solution and will evaluate the influence of the bonding mode (pyridyl vs. those compoundstodate. pyridylidene) on the catalytic activity of the metal center.

[1] O’Brien C., Kantchev E., Valente C., Hadei N., Chass G., Lough A., [1] E. C. Constable, Chem. Ind., 1994,56. Hopkinson A., Organ M. Chem. Eur. J. 2006, 12,4743; Navarro O., [2] E. C. Constable, C. E. Housecroft, J. N. Lambert and D. A. Malerek, Marion N., Mei J., Nolan S. Chem. Eur. J. 2006, 12,5142. Chem. Comm., 2005,3739. [2] Raubenheimer H., Cronje S. Dalton Trans. 2008,1265; Albrecht M., [3] V. Chaurin, E. C. Constableand C. E. Housecroft, New J. Chem., 2006, Stoeckli-Evans H. Chem. Commun. 2005,4705. 30,1740. [3] J. Owen, J. Labinger, J. Bercaw, J. Am. Chem. Soc., 2004, 126,8247. INORGANIC AND COORDINATION CHEMISTRY661515 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 229 Inorganic and Coordination Chemistry 230

An efficient homogenous photocatalytic system for the reduction of pro- Ru/PNNP ComplexeswithCyclic PNNP ligands tons to hydrogen using aRhenium based photosensitiser MarcoRanocchiari andAntonioMezzetti* Benjamin Probst,Christoph Kolano,Peter Hamm,* Roger Alberto* Dept of Chemistryand AppliedBiosciences,ETH Zürich,CH-8093 Zürich Department of Chemistry, Winterthurerstr. 190, 8057 Zürich, Switzerland [email protected]

We have used Ru/PNNP complexesascatalysts in theasymmetric cyclo- propanationaziridinationofolefins.1 In this reaction, a trans-carbene com- plex must be formed to achieve high enantioselectivity.Therefore,toin- creasethe rigidity of thePNNP ligandand enforcethe formationoftrans- adducts,wepreparedthe firstchiralmacrocyclic PNNP ligand(1)and the

corresponding ruthenium(II) complex[RuCl2(PNNP)] (2), which is ex- pected to form more rigidand stable catalysts upon chloride abstraction. Cl P Cl Cl L PF6 L PF6 N N N L N N N N Ru Ru Cl Ru Ru P P TlPF P P P TlPF P P 6 N 6 Cl Cl L The solar production of hydrogen and oxygen from water remainsamajor linear PNNP cangive cis-
isomers only trans-isomerspossible challenge forthe coming century. withacyclic PNNP We wish to report asuccessful implementation of an homogenousproton Thesynthesisisperformedinfour stepsstartingfrom1,2-bis(phenyl- reduction cycleasshown above for the production of hydrogen from light phosphino)ethane andcan be easily scaled up. Themostaccessibledia- and an irreversible electron donor. To our knowledge this is the first artifi- stereoisomer is obtainedfrom(R,S)-2,2'-(ethane-1,2-diylbis(phenylphos- cial mimetic for Photosystem Iemploying aRheniumbasedcomplex, phinediyl))dibenzaldehyde (1)in50% overall yield. Applications of 2 in [ReBr(CO)3bipy] as chromophore. To overcome the activation barrier for asymmetric catalysis will be reported. O protonreduction aCobalt based catalyst, [Co(dmgH)2], is used. Electron O O H H tBuOK 10%HCl transfer betweenthe antenna and the later was observed by timeresolved P P + O infrared spectroscopy, revealing aforwardelectron transfer rate of Ph Ph 18-crown-6 thf P P 8 -1 -1 Cl Ph Ph k1 =2.5 ±0.1·10 M ·s .Furthermore we could show that asecond order 1 process in cobalt is crucial for the final H2 generation step, implying aho- O O molytic H2 formation. Under ambient light conditions the process is con- [RuCl (DMSO) ] H2N NH2 2 4 Cl [1] N N N N trolled by photon flux. P P Ru Presently we focus on the linking of our system to an oxidative counterpart. Ph Ph P P P Cl P Ph Ph Ph Ph 2 [1] B. Probst, Ch. Kolano, P. Hamm, R. Alberto, submitted for publication. [1]Bonaccorsi, C.;Mezzetti, A. Organometallics 2005, 24,4953.

Inorganic and Coordination Chemistry 231 Inorganic and Coordination Chemistry 232

Ru(II)arene complexes as versatile anticancer agents Postsynthetic Modification of Mesoporous Silica: Methods, Tools, and Perspectives Anna K. Renfrew,and Paul J. Dyson* Hanna Ritter,Jan Hinrich Ramm,Nando Gartmann, Dominik Brühwiler* Ecole polytechnique fédérale de Lausanne, Institut des sciences et ingénierie chimiques, LCOM, CH-1015 Lausanne, Switzerland. Institute of Inorganic Chemistry, University of Zürich Winterthurerstrasse 190, 8057 Zürich, Switzerland Ruthenium based compounds are an attractive alternative to clinically used platinum drugs due to several features; awide range of accessible oxidation Postsynthetic modification is among the most popular methods for the states, varied synthetic chemistry and low toxicity. One series of Ruthe- preparation of functional mesoporous silica [1]. This can be attributed to the nium(II)-arene-pta (RAPTA; pta =1,3,5-triaza-7-phophaadamantane) com- fact that the separation of the mesoporous silica synthesis and functionaliza- pounds have been foundtoshow particularly highselectivity towards cancer tion steps allows an independentand straightforward control of pore size, cellsinboth in vitro and in vivo studies.1 By varying the ligand sphere, it is periodicity, particlesize,and particlemorphology. Current problems include possible to control the reactivity and cytotoxicity of the complexes. For ex- the control of the uniformity of surface functionalization, the reliable deter- ample, using aweakly coordinating arene ligand such as C H CF or mination of the functionalization degree, and the analysis of the distribution 6 5 3 of the functional groups on the mesoporous silica surface. We are presenting FC6H4CH3 facilitates arene lossallowing increased binding to double stranded DNA Alternatively compounds containing chelate phosphine li- new methods and analytical tools to solve these problems [2,3]. gands show reduced hydrolysis rates and much lower reactivity towards DNA though cytotoxicities remain high.

Figure 1: RAPTA-FT and RAPTA-PO

[1] C. Scolaro, A. Bergamo, L. Brescacin, R. Delfino, M. Cocchietto, G. Laurenczy, T. J. Geldbach, G. Sava, P. J. Dyson, J. Med. Chem. 2005, [1] F. Hoffmann, M. Cornelius, J. Morell, M. Fröba, 48,4161-4171. Angew. Chem. Int. Ed. 2006, 45,3216. [2] H. Salmio, D. Brühwiler, J. Phys. Chem. C 2007, 111,923. [3] H. Ritter, C. Schütze, D. Brühwiler, in preparation. INORGANIC AND COORDINATION CHEMISTRY661616 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 233 Inorganic and Coordination Chemistry 234 FluorescenceSensors for Lithium Ions Kinetic Resolution of ChiralPhosphodiesters by Artificial Metalloen- zymes Based on Biotin-Streptavidin Technology SébastienRochat,Kay Severin Thibaud Rossel,Christelle Schenk, Therese Wohlschlager, Alessia Sardo, Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale Marc Creus, Thomas R. Ward de Lausanne (EPFL), CH-1015 Lausanne, Switzerland University of Basel, Spitalstrasse 51, CH-4056 Basel, Switzerland Lithium-based drugs are widely used for patients suffering from bipolar disorders, and applications for the treatment of neurodegenerativedisorders In contrast to organometallic catalysts, enzymes are particularily efficient at have been suggested. However, the unavailability of asensitive and specific hydrolyzing inert phosphodiester and amide linkages. In abiomimetic spirit, Li+ tool severely limits investigations in this context.[1] incorporation of abiotinylated dinuclear metal complex in streptavidin af- fords artificial hydrolases for the kinetic resolution of racemic phospho- Macrocyclicreceptors, which are known to be water-soluble and selective diesters. Achemogenetic optimization scheme allows to optimize both the for lithium ions, have been developed in our laboratory.[2] When afluores- activity and the selectivity of the artificial metallonuclease. Combining, ki- cent dye is attached to them, they can be used to determine the lithium con- netic data, mutagenesis and screening of various substrates allows us to centration in an aqueous solutionbyasimple fluorescence measurement. present ahypothesis on the key enantiodiscriminating interactions which afford exquise E selectivity factors. In addition, our recent efforts on ds- Sensors of this kind may find applications in biomedical investigations in- DNA hydrolysis with these artificial nucleases will be presented. volving lithium-based drugs.

[1] D. M. de Freitas, M. M. C. A. Castro, C. F. G. C. Geraldes, Acc. Chem. Rev. 2006, 39,283-291. [2]Z.Grote,R.Scopelliti, K. Severin, J. Am.Chem. Soc. 2004, 126, 16959-16972.

Inorganic and Coordination Chemistry 235 Inorganic and Coordination Chemistry 236

Syntheses of Vitamin B12-Pt(II)Conjugatesand TheirApproach as Structural Investigation of an Axial Lanthanide Podates in Solution Therapeutic Drug Delivery Using Paramagnetic NMR

Pilar Ruiz-Sáncheza,JorgeC.Escalante-Semerenab,Stefano Ferraric and P. E. Ryan,G.Canard,C.Piguet* Roger Albertoa Department of Inorganic, Analytical and Applied Chemistry. University of a ACI-University of Zurich, Winterthurerstr. 190, CH-8057 Zürich, Swit- Geneva, 30 quai E. Ansermet, CH-1211 Geneva 4, Switzerland. zerland, b University of Wisconsin, University Avenue 1710, WI-53706 Madison, USA, c IMCR-University of Zurich, Winterthurerstr. 190, CH- The effective concentration ceff is ameasure of the advantagesofintra- over 8057 Zurich, Switzerland intermolecular connection events. In coordination chemistry, it may be used to estimatethe extent to which the degree of preorganization of aligand Since fast proliferating cellsare high B12 consumers, Pt-conjugation to the benefits itsability to selectively complex various lanthanide Ln(III) ions. A eff cyanide of B12 can be used for specific targetingofcancer cells and thera- recent thermodynamic study has investigated the impact of c on the stability peutic drug delivery, thereby avoiding the dose-limiting toxicity of cis- of apre-organised nonadentate tripod (1)with respect to three separated 1 platin. We could show that the Pt(II) complexes released from B12 after analogous tridentatebinding units. Both systems form triple-helical com- reduction exerted acytotoxicity comparable to that of cisplatin itself.2 plexes with Ln(III) ions, but, surprisingly, ceff drasticallydisfavours the po- Furthermore, the chloride ligands of Pt(II) in theseconjugates could be ex- date, evenifboth structures are superimposable in the solid-state. Moreover, changed by from fluorescence markers, antibiotics or radiopharmaceuticals. the size of the lanthanide ion doesn’t seem to have asignificant influence on eff 1 The coordination of 2-deoxyguanosine to the released Pt(II) from B12 al- c in this particular case. To better understand this phenomenonwehave lowedtoisolate and characterize the Pt(II) species released from adenosyla- studied the solution structure of Ln(III) complexes of the tripodal receptor (1) tion assays and to follow its biological fate. using paramagnetic NMR. In doing this we have been able to ascertain 57 57 Due to the long half-lifeof Co, Co-vitamin B12 has avery limited use for whether or not the apparent unfavourable ceff is due to amajor change in 3 humansand imaging of B12 metabolism in tumorisalmost imposible. We structure along the lanthanide series (Ce-Yb). This poster will presentand proposed anovel radiolabeled B12 without modificationofthe B12 molecule discuss the results obtained from the paramagnetic NMR investigation. - 131 + 4 by exchange of Cl for Iin[{B12}-CN-{cis-PtCl(NH3)2}] . Preliminary cancer cell uptake studies will be presented.

[1] Lippert, B. Cisplatin; Wiley-VCH, 1999. [2] Ruiz-Sánchez, P; Mundwiler, S.; Spingler, B.; Buan N.R.;Escalante- Semerena,J.C.;Alberto, R. J. Biol.Inorg. Chem. 2008, 13,335. [3] Collins, A.C.; Hogenkamp H.P.C.; Gebhard M.W. Mayo Clin. Proc. 1999, 74,687. 1 [4] Ruiz-Sánchez, P; Mundwiler, S.; Medina-Molner, A.; Spingler, B.; Al- berto, R. J. Organomet. Chem. 2007, 692,135 [1] Canard, C.; Koeller, S.; Bernardinelli, G.; Piguet,C.J. Am. Chem. Soc. 2008, 130, 1025. INORGANIC AND COORDINATION CHEMISTRY661717 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 237 Inorganic and Coordination Chemistry 238

Ru /PNNP Catalyzed Asymmetric Aziridination of Imines Highly variable N1HC6 ligands: Normal, abnormal and remote bonding in pyridylidene complexes Christoph Schotes, Marco Ranocchiari and Antonio Mezzetti* Oliver Schuster,Elzet Stander-Grobler, Anneke Krüger, Gerrit Julius, Dept. Chem. and Appl. Biosciences, ETH Zürich, CH-8093 Zürich Helgard G. Raubenheimer

Aziridine-2-carboxylates are valuable precursors for α-and β-amino Department of Chemistryand Polymer Science, University of Stellenbosch, acids. We report herein theasymmetricsynthesis of these versatileorganic PrivateBag X1, Matieland, 7602,South Africa compounds by catalyticaddition of acarbenespeciestoaromatic imines. [RuCl2(PNNP)] complexes undergo chloride abstraction upon treatment While the termN-heterocycliccarbene (NHC)iswidely employed as asyn- with chloride scavengers to give [RuCl(PNNP)]+ (1).Complex 1 forms the + onym for 2-imidazolylidenes and related ligands (i.e. five-membered rings six-coordinate species [RuCl(L)(PNNP)] when exposedtooxygen- with two N-atoms adjacent to the carbenecarbon), there is agrowing inter- containing ligands like water and Et2O(L), and is an efficientenantio- est in NHC ligands with reduced heteroatom stabilisation selective catalystfor atom-transfer reactions [1][2][3]. We findnow that 1 e.g. pyrazolylidenes,4-imidazolylidenes, pyridylidenes).Our grouphas catalyzes the aziridination of N-benzhydryl protected imines 2a-f,togive been particularly interested in the complexchemistry of pyridinium-derived 3a-f in up to 28%yield and with 25% ee with complete cis-selectivity. carbenes which offer avariety of bondingmodes (see Figure)[1]. CHPh PF CHPh 2 6 2 N CO Et H H N 2 2 N H H N N Cl N N catalyst CO2Et N Ru (5 mol%) P P Ia IIIa Ph2 Ph2 R CH2Cl2 R

1 2a -e 3a -e

R=H, NO2,OMe,F,CF3 H H H N N N Addition of water or Et2OtoaCH2Cl2 solution of 1 increasesthe enantioselectivity to more than 70% ee. We are studyingthe detailsofthe mechanism in order to increase the enantioselectivity and suppress the Ib II IIIb formation of maleate, which limits the yield of 3a -e. Herein we report the first comparative investigation of isomeric [1] C. Bonaccorsi, A. Mezzetti, Organometallics 2005, 24,4953. normal(nNHC - I), abnormal (aNHC-II)and remote (rNHC - III) [2] C. Bonaccorsi, M. Althaus, C. Becker, A. Togni, A. Mezzetti, Pure pyridylidene complexes. Both experimental and computational studies on + Appl. Chem. 2006, 78,391. compoundsofthe general formula [trans-(NHC)M(PPh3)2Cl] (M =Pd, Ni) [3] M. Althaus, C. Becker, A. Togni, A. Mezzetti, Organometallics have been carried out. 2007, 26,5902. [1] H. G. Raubenheimer, S. Cronje, Dalton Trans. 2008,1265.

Inorganic and Coordination Chemistry 239 Inorganic and Coordination Chemistry 240

Synthesis and Structural Determination of Phases in the Evaluation of Organometallic Technetium and Rhenium Thymidine XSiSn Systems (X=AE, Ln) Complexes as Substrates for Human Thymidine Kinase Type 1

Liz Stalder,Reinhard Nesper and Michael Wörle Harriet Struthers,1 Anja Stoffel,2 Leonardo Scapozza,2 Roger Schibli1

Lab. of Inorg. Chem., ETH-Hönggerberg, Wolfgang-Pauli-Strasse 10, 1Institute for Pharmaceutical Sciences, Department of Chemistry and CH-8093, Zürich, Switzerland. Applied Biosciences, ETH, 8093 Zurich. 2School of Pharmaceutical Sciences, University of Geneva, 1211 Geneva. Anew Zintl phase Ba8Si6Sn was synthesised from the elements. Single- crystal analysis shows that it crystallises in the Pbcn space group (orthor- Human cytosolic thymidinekinase (hTK1) shows ahigher than normal ex- o hombic, N 60) with a=8.784(5)Å, b=8.765(5)=Å and c=27.20(2)Å. Inte- pressioninawide varietyofcancer cells. Technetium labeledthymidine 6− 4− restingly, the structure contains Si3 units and Sn anions with acounter- analoguestherefore have thepotential to act as markers for cancer cellproli- intuitive charge distribution. It is related to the previously reported feration. Click chemistry canbeused to introduce aseries of different che- Ba8Si6Br4 structure[1].Inthe case of Sr and Eu, no analogous structure was 99m lating systems for the M(CO)3 core(M= Tc, Re) into molecules of bio- found. logical interest.[1] This approach was used to facilitate the synthesis of a series of thymidine derivatives functionalized with achelating system at the C3' position of thymidine, startingfrom the commercially availableprecur- sor 3'-azido-3'-deoxythymidine (AZT). By varying the chelatingsystem, neutral, cationic and anioniccomplexes could be readilysynthesized. Incu- bation of the complexeswith hTK1 and ATP identified the first organome- tallic substrates of hTK1 in which thymidine is modified at the C3' position. The synthesis, characterization and relative phosphorylation rates of the novel complexescompared to the natural substrate thymidinewill be pre- sented. HO HO O O O O O HO O N N N NH O N N 2 O N N N O O H NOH 2 O N O M O N O M N3 OC CO OC CO N "M(CO) " H H OH 3 CO CO From areactionofSr, Si and Sn in aratio of 2:1:1acrystal wasselectedand O N O o H O O HO OH analysed. It crystallisesinthe Cmcm space group (orthorhombic, N 63) M=99mTc, Re O AZT NH with a=4.976(3)Å b=11.736(6)Å and c=4.306(2)Å. The refinement indi- N N H N N N N N M catedamixedoccupancy on the Si/Sn site and gives acomposition of O N O OC CO H CO SrSi0.5Sn0.5. [1]Steffen Wengert, Johannes B. Willems and Reinhard Nesper, Chem. [1]H.Struthers, B. Spingler, T. L. Mindt, R. Schibli, Chem.--Eur. J. 2008, Eur. J., 2001, 7,3209. in press. INORGANIC AND COORDINATION CHEMISTRY661818 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 241 Inorganic and Coordination Chemistry 242 Homolysis of peroxynitrous acid induced by laser flash photolysis Supramolecular Trojan Horse for Cancer Cells

Manuel Sturzbecher,Thomas Nauser, Bruno Therrien Reinhard Kissner, Willem H. Koppenol* Institut de Chimie, Université de Neuchâtel, Case postale 158, 2009 Department of Chemistry and Applied Biosciences, ETH Zurich, Neuchâtel, Switzerland Wolfgang-Pauli-Strasse 10, CH-8093 Zurich, Switzerland Combining the “molecular clip”strategy developed by Stang and the “mo- We have recently shown that homolysis of ONOO– at the N–O bond oc- lecular panelling” strategy developed by Fujita, we recently synthesised the –1 [1] i curs with arate constant of 0.020 ±0.001 s . From this rate constant and "complex-in-a-complex" cations [(acac)2Pd⊂Ru6(p-Pr C6H4Me)6(tpt)2- 6+ i 6+ other data, it is possible to calculate athermodynamically derivedrate con- (dhbq)3] and [(acac)2Pt⊂Ru6(p-Pr C6H4Me)6(tpt)2(dhbq)3] ,inwhich the stant for the homolysis of ONOOH, 0.38 ±0.25 s–1,for reaction −2. An bis(acetylacetonato)Pd or Pt complexes are encapsulatedinthe hexa- i 6+ [1] optional pathway is reaction 3, which would yieldproducts that lie ruthenium cage [Ru6(p-Pr C6H4Me)6(tpt)2(dhbq)3] . 20 kJ mol–1 abovethe products of reaction 2. To examine this possibility, we used acombined stopped-flow –laser flash photolysis apparatus to de- termine whether photons cause homolysis of ONOOHvia reaction 2or3. – ● ●– ONOO =NO+O2 (1) ● ● ONOOH= NO2 +HO (2) ● ● ONOOH =NO+HO2 (3) We found that absorptions increased in the wavelength range of 235 to 310 nm after excitation at 355 nm, and that these absorptions increase with pH in the range 4–5.5. This suggests strongly that the absorbing species are • •– • •– HO2 and O2 ,given the known pKa of 4.8 of HO2 and O2 ,which absorbs • more strongly than HO2 . In order to clarify whether the O–O or N–O bond breaks, we determined • • the concentrations of HO ,<1μM,and HO2 ,>20μM, respectively, which clearly indicates that the induced homolysis takes place at the N–O bond. The cytotoxicityofthe two host-guest systems,the empty hexaruthenium Furthermore, we observed asecond–order recombination,which ends at cage andthe free complexesPd(acac)2 and Pt(acac)2 havebeen evaluated as the initial absorption level. Hence, we calculated arate constant of anticancer agent against A2780 human ovarian cancer cells. The difference (2.1 ±0.6) ×1010 M–1s–1 forthe NO• and HO • recombination, within the in cytotoxicity of the different systems suggests that like a“Trojan Horse”, 2 once inside acell, passive leaching of the guest from the cage accelerates erroridentical to that of the reaction of NO• with the O •–.[2] 2 and increases the cytotoxic effect. [1] Sturzbecher, M., Kissner, R.,Nauser T., Koppenol W.H., Inorg.Chem. 2007, 46,10655. [1] B. Therrien, G. Süss-Fink, P. Govindaswamy, A. K. Renfrew, P. J. Dy- [2] Nauser,T., Koppenol, W.H., J.Phys.Chem.A 2002, 106,4084. son, Angew. Chem. Int. Ed. 2008, 47,inpress.

Inorganic and Coordination Chemistry 243 Inorganic and Coordination Chemistry 244

ATRA and ATRC Reactions Catalyzed by aMixture of Molecular Mechanics Modeling of the Trans Influence in [Cp*RuCl2(PPh3)] and Mg Organometallic Complexes Applied to Asymmetric Catalysis

Katrin Thommes and Kay Severin I. Tubert-Brohman*,M.Schmid, M. Meuwly

Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale University of Basel. Klingelbergstrasse 80, 4056 Basel, Switzerland de Lausanne (EPFL), CH-1015Lausanne, Switzerland Efficient calculation of metal-containing complexes relevant to catalysis is The main disadvantage of active Ru catalysts for atom transfer radical addi- of major interest for better characterizing and optimizing the catalysts. tion (ATRA)and cyclization (ATRC)reactionshas been their low stability. Based on an existing force field for organometallic compounds III The combination of the air-stable Ru complex [Cp*RuCl2(PPh3)] with Mg (VALBOND[1]), extensions to include electroniceffects such as the trans allows to perform these reactions under mild conditions with high efficiency influence of ligands on the bond lengths and energies are discussed. Para- [1]. It is suggested that Mg acts as areducing agent that generates and rege- meters and results for model octahedral complexes of Ru, Os,Rh, andIrare nerates the catalytically active RuII species. presented, as well as an applicationtothe study of reactive intermediates Cl Cl involved in asymmetric hydrogenation catalyzed by iridium complexes with O O chiral phosphinooxazolines (PHOX) ligands. The new force field allows for Cl2HC O O the separation of electronic and steric effects on the stability of different +Mg geometric isomers and reproduces DFT results which are consistent with Ph Cl Ph Cl experimental observations

CCl3 Cl O O [1] C. R. Landis, T. Cleveland, T. K. Firman. J. Am. Chem. Soc. 1998, 120, Intramolecular ATRA reactions are especially interesting from asynthetic 2641. point of view. With the new system, cyclizations can be performed under mild conditions with low catalyst loadings and good stereoselectivities. So far, consecutive reactions using ATRA and ATRC products have been rare or mainly limited to cyclization products [2]. In this context, possible following transformations are investigated. They would be of great interest for tandem catalysis reactions, which have attracted alot of attention in or- ganic synthesis.

[1] K. Thommes, B. Içli, R. Scopelliti,K.Severin, Chem. Eur. J., 2007, 13, 6899. [2] C. D. Edlin, J. Faulkner, P. Quayle, Tetrahedron Lett. 2006, 47,1145. INORGANIC AND COORDINATION CHEMISTRY661919 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 245 Inorganic and Coordination Chemistry 246

99 + Crystal Structures and Diffuse Scattering of Compounds with [ TcO3] complexes as model compound for anovel direct labeling Graphite-like (B,C)-Nets strategy for radiopharmaceutical applications

Michael Wörle,Daniel Widmer, Fabian von Rohr, Frank Krumeich, Rein- Yuji Tooyama,Henrik Braband and Roger Alberto hard Nesper University of Zürich, Winterthurerstr. 190, CH-8057 Zürich, Switzerland Laboratory of Inorganic Chemistry, ETH Zürich, Wolfgang-Pauli-Stasse 10, 8093 Zürich, Switzerland Molecular imaging emerged as anovel and powerful strategy for the visua- lization of biological events in amolecular level. Due to its availability and 99m The crystalstructures of the new compounds Ca(B,C)6 (hexagonal, a= physical properties Tc is still the favored radionuclide for radioimaging purposes. In the past decades labeling strategies for Tc were mainly based on 4.563 Å, c=4.396(1) Å) and Ca(B,C)8 (hexagonal, a=2.588(1) Å, c= 4.434(1) Å) were determined from powder diffractiondata. The compounds the bifunctional chelator concept. Here we report about acompletely new consist of planar graphite-like (B,C)-nets, intercalated by calcium atoms. In strategyfor the direct labeling of biomolecules. [99TcO ]- canbeactivated by strong lewis acids in organic solvents, the Ca(B,C)6 one third of the hexagonal prismatic voids formed by the (B,C)- 4 highly active intermediate can be substituted by bi- or tridentated ligands and layers is occupiedbyCa. In Ca(B,C)8 the Ca-atoms are disordered, which 99 [1] gives rise to honeycomb-like diffuse scattering visible in the electron dif- yield the corresponding { TcO3}complexes. It is known that {TcO3} [2] fraction pattern (Fig.1a). Amodel for the calcium distribution was devel- complexes react with alkenes by a[2+3] reaction .This reaction could offer oped and the diffuse scattering could be simulated successfully with the anew wayfor labeling of biomolecules containing double(or triple) bounds. 99 program DISCUS [1] (Fig. 1b). We investigated this reaction with aseries of { TcO3}model complexes and biological relevant model alkenesindetail.Inall cases arelatively fast biomolecularreaction occurredunder quantitative formation of the corres- ponding 99TcV complex (e.g.figure 1). The kinetic data we optioned for this reactions support an associatively driven mechanism.

L L L L L L alkene Tc Tc O O O O O O R

+ Scheme. Thereducingreactionof[TcO3] type complexes by alkenes Fig.1 the crystalstructure of [(tpzm*)TcO(1-phenyl-1,2-ethanediolate)] (L =bi- or tridenate ligands,R=H,Ph, PhSO4 andalkyl group)

[1] Proffen T., Neder T., J. Appl.. Cryst., 1997, 30,171 [1] Y. Tooyama, H. Braband, B. Spingler, R. Alberto, et al, Inorg. Chem. 2008, 47,257. [2] M.Ronald and Alan Davison. Polyhedron 1988, 7,1981-1989

Inorganic and Coordination Chemistry 2472Inorganic and Coordination Chemistry 48

Investigation of Lanthanide Complexes with aFamily of Tripodal Bi2O3 Nanowires: Structure Control and Visible-Light-Driven Photoca- Ligands talytic Activity

Soumaïla Zebret,Josef Hamacek Ying Zhoua,Kathrin Vuillea,Andre Heelb,Greta R. Patzkea*

Department of Inorganic, Analytical and Applied Chemistry, University aInstitute of Inorganic Chemistry, University of Zurich, Winterthurerstrasse of Geneva, 30 quai E.-Ansermet,CH-1211 Geneva 4, Switzerland. 190, CH-8057, Zurich, Switzerland bEMPA, Swiss Federal Laboratories for MaterialsTesting and Research, Recently, several tripodal [1] were prepared in order to develop stable High Performance Ceramics, Ueberlandstrasse129, CH-8600, Duebendorf, binding Ln(III) luminescent and paramagneticdevices. Herein we report Switzerland on the synthesis of tripodalligands L1, L2 and L3,which have been designed for Ln (III) coordination by taking advantage of the chelating The five polymorphic forms of bismuth trioxide, including α-, β-, γ-, δ-and effect of 2,6-dicarbonylpyridine subunits. ω-type, display high dielectric permittivity, high oxygen conductivity as R well as remarkablephotoconductivity. Therefore, Bi2O3 is widely used in N O N gas sensors, optical coatings, photovoltaic cells, photocatalysts, and related N R L1:R=−COOMe applications[1].The availability of Bi O nanowiresmay bring forward new N O 2 3 L2:R=−CO-N(CH2-CH3)2 types of applicationorenhance the performance of the currently existing O N L3:R=−COOH devices. Despite its high application potential, up to now, only few re- N searchers have developed synthetic pathways towards one-dimensional (1D) [2, 3] R nanostructured Bi2O3,and most of them are based on gas phase methods . To the best of our knowledge, alarge-scale solution-based synthesis of dif- The Ln(III) complexes with L1 and L2 are characterised in acetonitrile ferent modifications of 1D nanostructured Bi2O3 has not beenachieved until by spectrophotometry,NMR and ES-MS titration. Interestingly, the now. Here,wereportasimplemethodfor the selective synthesis of different reaction of L2 with Ln (=Eu-Lu) provides tetrahedral tetrametallic Bi2O3 nanowiresthrough hydrothermal treatment of commercial Bi2O3 complexes [2]. In addition, thermodynamic parametersand powdersinthe presence of ionic additives. Furthermore, the relationship photophysical propertiesofEu(III) complexes with L1-L3 will be between the photocatalytic activities and the morphology of Bi O and re- discussed. 2 3 lated ternary compounds, such as bismuth tungstates/vanadates, was inves- tigated through the degradation of organic compounds (methyl orange, me- [1]M.Seitz, M. D. Pluth, and K. N. Raymond, Inorg. Chem. 2007, 46, thylene blue) under visible-lightirradiation. 351; J.-M. Senegas,G.Bernardinelli, D. Imbert, J.-C. G. Bünzli, P.-Y. Morgantini, J. Weber, and C. Piguet, Inorg. Chem. 2003, 42, [1] F. Gao, Q. Lu, S. Komarneni. Chem. Comm. 2005,531. 4680. [1] F. Gao,Q.Lu, S. Komarneni. Chem. Comm. 2005, 531-533. [2] J. Hamacek,G.Bernardinelli, Y. Filinchuk, Eur. J. Inorg. Chem. [2] Y. Qiu, D. Liu, J. Yang, S. Yang. Adv. Mater. 2006, 18,2604. 2008,Submitte [3] G. R. Patzke, Y. Zhou. Mater. Res. Soc. Symp. Proc. 2008, 1056,1056- HH05-01. INORGANICAND COORDINATION CHEMISTRY/ORGANIC CHEMISTRY662020

doi:10.2533/chimia.2008.620 CHIMIA 2008, 62,No. 7/8

Inorganic and Coordination Chemistry 249 Organic Chemistry 250 Ligand-Mediated Decarbonylation as an Efficient Synthetic Method to Rotaxanes via Palladium Active-Metal Template Strategies Re(I) and Re(II)Dicarbonyl Complexes José Bernà, James D. Crowley, Stephen M. Goldup, Kevin D. Hänni, Fabio Zobi,Bernhard Spingler and Roger Alberto Ai-Lan Lee and David A. Leigh

Institute of Inorganic Chemistry, University of Zürich, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, UK. Winterturerstr. 190, CH-8057 Zürich ,Switzerland ([email protected])

Chemistry of rhenium (II) is the least developed among the eight common In contrast to the classic ‘passive template’ approach,[1] an ‘active-metal’ oxidations states of this element. This is likely to be true due to alack of templatestrategy[2] involves ametal center which acts as both atemplate versatile Re(II) precursors as starting material. Compounds of d5 Re areat- and the catalyst for covalent bond formation in the construction of mechani- tractive for medicinal inorganic chemistry and as precursors for single- cally interlocked architectures. [1]-[2] Alkyne Homo-coupling: molecule magnets. Asynthetic approach to Re(II) complexes would +non-interlockedthread N O O therefore be useful for asystematicexploration of the reactivity patterns of N O O Cl Pd Cl H CuI CuCl these molecules. We present an efficient high yield synthesis of Re(I) and N + O O DIPA O O 0 Re(II) dicarbonyl complexes via an unprecedented ligand-mediated decar- O O R Pd 1equiv. 2.5 equiv.

bonylation (LMD) reaction.Weshow that the LMD may be considered as 43% (catalytic version: 90%) + Oxidative-HeckCross-coupling: generally applicable to fac-[Re(CO)3] complexes of tridentate aliphatic +non-interlocked thread N N amine ligands. Structural authentication of key intermediatesispresented. N N 1equiv. O O O O O Pd(OAc)2 10 mol% O RO CHCl3/DCM 1:1 + O O O (HO) B Benzoquinone, O2 2 O O O O 1equiv. O OR 2equiv.

R=(CH2)3C6H4C(C6H4tBu)3 73% (1 mol% Pd: 66%) Palladium-catalyzed reactions areoften the method of choice for the forma- tion of C-C bondsinchemical synthesis. The development of both homo[3] and heterocouplings[4] basedonPdactive-metal templates opens the possi- bilitytouse these methodologies for the assemblyof[2]rotaxanes. The reac- tions are mild, high-yielding, versatileand only acatalytic amount of the template is required.

[1]M.C.Thompson, D. H. Busch, J. Am.Chem. Soc. 1964, 86,3651-3656; [2] V. Aucag- [1] E. J. Schelter, F. Karadas, C. Avendano,A.V.Prosvirin, W. Wernsdor- ne, K. D. Hänni,D.A.Leigh, P. J. Lusby, D. B. Walker, J. Am. Chem. Soc. 2006, 128, fer and K. R. Dunbar, J. Am. Chem. Soc.,2007, 129,8139-8149. 2186-2187;[3] J. Bernà, J. D. Crowley, S. M. Goldup, K. D. Hänni, A.-L. Lee, D. A. Leigh, Angew. Chem. Int.Ed. 2007,46,5709-5713; [4] J. D. Crowley, K. D. Hänni, A.-L. [2] E. J. Schelter, A. V. Prosvirin, W. M. Reiffand K. R. Dunbar, Angew. Lee, D. A. Leigh, J. Am. Chem. Soc. 2007,129,12092-12093. Chem. Int.Ed.,2004, 43,4912-4915.

Organic Chemistry 251 Organic Chemistry 252

Synthesis, properties andapplications of Nickel(II) The Biomimetic Synthesis and Final Structure Determination of bisimidazol-2-ylidenecomplexes (–)-Centrolobine

DanielaF.Bossi,Roger Mafua, Titus A. Jenny Frank Rogano,PeterRüedi*

UniversityofFribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland Institute of Organic Chemistry, University of Zürich, Winterthurerstr. 190, CH-8057Zürich, Switzerland Since their discovery [1], N -heterocyclic carbenes(NHCs) especially de- rivedfrom imidazolium salts have been used as ligands in different organo- In previous work we have shown that 2,6-disubstituted tetrahydropyrans metallic catalysis [2],but fewhave been used for olefinpolymerisation. could be biomimetically synthesized by oxidative cyclization of their On the other side, the growingimportanceofnickelcomplexes as olefin correspondingphenolic alcohols[1]. polymerisation catalysts [3], led us to developanew olefin polymerisa- tion catalyst containing bisimidazoliumligands. OH (+)-(S)-3:R1=Me, R2=H (Š)-(R)-3:R1=Me, R2=H (+)-(S)-4:R1=H,R2=Me R1O OR2 (Š)-(R)-4:R1=H,R2=Me N N N N

N Ni N N Ni N Cl Cl Cl Cl (R)((S)(S)R) O O

R2O OR1 R2O OR1 1 2 (+)-1:R1=H,R2=Me (Š)-1:R1=H,R2=Me (+)-2:R1=Me, R2=H (Š)-2:R1=Me, R2=H In this work, the synthesis of twonew nickel(II) bisimidazolium-2-ylidene complexesisdescribed. They are obtained by transmetalation from the In order to correct structural inconsistencies of (–)-centrolobine ((–)1)[2], corresponding silver carbenecomplexes. Surprisingly the twocomplexes aphysiologically active constituent of Centrolobium robustum [3], the differ very much both withrespect to structure and catalyticbehaviour. congeners 1 and 2 were preparedfrom theirprecursors 3 and 4 (ee >99%). Most interestingly theviolet pseudotetraedric complex 2 reversibly binds The key step is the oxidative cyclization by DDQ, abiomimetic equivalent dioxygen, afeaturetotallyabsentinthe square planarcomplex 1. of phenoloxidase. [1] P. Rüedi, M. Juch, Curr. Org. Chem. 1999, 3,623. [1] A. J. Arduengo, R. L. Harlow, M. Kline, J. Am.Chem. Soc., [2]L.V.Alegrio, R. Braz-Filho, O. Gottlieb, Phytochemistry 1989, 28,2359; A. 1991, 113,361-363. F. de C. Alcântara, M. R. Souza, D. Piló-Veloso, Fitoterapia 2000, 71,613; [2] W. A. Herrmann, Angew. Chem. Int. Ed., 2002, 41,1290- V. Böhrsch, S. Blechert, J. Chem. Soc., Chem. Commun. 2006,1968. 1309. [3]I.L.DeAlbuquerque,C.Galeffi, C. B. Casinovi, G. B. Marini-Bettòlo, Gazz. [3] S. Benson,B.Payne, R. M. Waymouth, J. Polym. Sci., Part Chim. Ital. 1964, 94,287. A: Polym. Chem., 2007, 45,3637-3647.