References 59 (a) A. G. M. Barret, S. P. D. Baugh, V. C. Gibson, M. R Gilles, E. L. Marshall and P. A. Procopiou, 38 G. C. Fu and R. H. Grubbs,]. Am. Chem. Sot., 1993, Chem. Commnn., 1996,2231; (b) A. G. M. Bmet, S. P. 115,3800 D. Baugh, V. C. Gibson, M. R Gilles, E. L. Marshall 39 M. Schuster and S. Blechert, Angew. Chem., Int. Ed and P. A. Procopiou, Cbem. Commnn., 1997,155 Engl., 1997,37, 2036 60 S. Chang and R H. Grubbs,]. OE. Cbem., 1998,63, 40 S. K. Annsaong, J. Cbem. SOC.Per& Truns. I, 1998, 864 371 61 J. P. A. Harrity, M. S. Visser, J. D. Gleason and A. 41 R R Schrock, J. S. Murdzek, G. C. Bazan, J. H. Hoveyda,]. Am. Cbm. Soc., 1997,119,1488 Robbins, M. DiMare and M. O'Regan, J. Am. Cbem. SOC.,1992, 112, 3875 The Authors 42 G. C. Fu and R H. Grubbs,J. Am. Cbem. Soc., 1992, Professor A. T. Balaban, a member of the Romanian Academy, 114,5426 taught organic for over 40 years, until 1999, at Bucharest Polytechnic University. He now teaches at Texas A & M 43 G. C. Fu and R H. Grubbs,]. Am. Cbm. Soc., 1992, University, Galveston, TX. His interests include homogeneous 114,7324 , heterocyclic compounds (pyrylium, pyridinium, oxazole), 44 P. R Hanson and D. S. Stoianova, Tetrahedmn stable free radicals, and theoretical chemistry including chemical LettJ999, 40, 3297 applications of graph theory and topological indices. 45 M. Lautens and G. Hughes, 13th Int. Symp. on kana Dragutan is a Senior Researcher at the Institute of Organic Olefin Metathesis and Related Chemistry, Rolduc, Chemistry of the Romanian Academy. Her research interests Kerkrade, The Netherlands,July 11-15,1999, q. cit., include sterically hindered amines; synthesis of olefinic monomers (Ref. 5), Abstracts, p. 9 via olefin metathesis; stable organic free radicals as spin probes for ESR of organised systems and membrane bioenergetics; and 46 A. J. Phillips and A. D. Abell, Akiicbim. Ah, 1999, transition metal complexes with free radical ligands. 32,75 47 (a) S. J. Miller, H. E. Blackwell and R. H. Grubbs,J. Valerian Dragutan is a Senior Researcher at the Institute of Organic Am. Cbm. Soc., 1996,118,9606; @) F. P. J. T. Rutjes Chemistry of the Romanian Academy. His current research and H. E. Shoemaker, Tetrahedron Lit, 1997,38,677 interests are homogeneous catalysis by transition metals and Lewis acids; olefin metathesis and ROMP of cycloolefins; bioactive 48 M. J. Moms and W. G. Stilbs, 10th Int. Symp. on organometallic compounds; mechanisms and stereochemistry of Chemistry, Poznan, Poland, 1993, reactions in organic and polymer chemistry. Absaacts, p. 267 49 B. Konig and C. Horn, Synhett, 1996,1013 Organoplatinum (IV) Polymers 50 (a) S. J. Miller, S. H. Kim, 2. R Chen and R. H. As hydrogen bonding can control the arrange Grubbs,J. Am. Cbem. SOC.,1995,117,2108; @) H. D. Maynard and R H. Grubbs, PobmerPnp. (ACS, Div. ment of molecules or ions in the solid state, it can P04mm Cbem.), 1998,39,523 be used in crystal engineering and in supramolecu- 51 G. W. Coates and R H. Grubbs, J. Am. Chem. SOC., lar synthesis. Some coordination 1996,118,229 complexes contain hydrogen bonds, but little has 52 A. Fursmer and N. Kindler, Teirnhedmn Lett., 1996, been done with hydrogen bonding in organometal- 37,7005 lic platinum complexes. 53 A. Kinoshita and M. Mori, J. 00 Cbem., 1996, 61, Now, researchers at the University of Western 8356 Ontario in Canada have produced a series of 54 (a) Z. Yang, Y. He, D. Vourloumis, H. Vallberg and organoplatinum(IV) complexes containing a range K. C. Nicolaou, Anp. Cbem., Znt. Ed Engl, 1997, 36, 166; @) D. Meng, D. S. Su, A. Balog, P. of functional groups which can take part in hydro- Bertinato, E. J. Sorensen, S. J. Danishefsky, Y. H. gen bondq (C. S. A. Fraser, H. A. Jenkins, M. C. Zheng, T. C. Chou, L. He and S. B. Horwitz,]. Am. Jennings and R J. Puddephatt, Otganometdh, 2000, Cbem. Soc., 1997, 119, 2733; (c) D. Schinzer, A. 19, (I)), 16351642). The organoplatinum(IV) com- Limberg, A. Bauer, 0. M. Bohm and M. Cordes, plexes were prepared by trans- of Angew. Chem., hit. Ed Engl., 1997,36, 523 alkyl halide reagents RCH,X (X = C1 or Br) to 55 IC C. Nicolaou, N. Wissinger, J. Pastor, S. Ninkovic, F. Sarabia, Y. He, D. Vourlounis, Z. Yang, T. Li, P. ptMez@uzbipy)], buzbipy = 4,4'-cl-tert-butyl-2,2'- Giannakakou and E. Hamel, Nu&n, 1997,387,268 bipyridine. Dimers were formed via OH-0 or 56 (a) J. S. Clark and 0. Hamelin, Angew. Cbem. Int. Ed, NH-0 hydrogen bonding, or polymers via 2000,39,372; (b) J. D. Rainier, S. P. Allwein and J. NH-Cl hydrogen bonding. Further derivatives M. Cox, OE. Lett., 2000,2,231 could be prepared by reacting the complexes 57 (a) K. Hammer and K. Undheim, Tetrubedron, 1997, formed with AgBF, in the presence of nicotinic 53, 230; @) H. E. Blackwell and R H. Grubbs, acid or 4,4'-bipyridyl, and one of these, with two Anp. Cbem. Int. Ed, 1998,37,3281; (c) T. D. Clark and M. R Ghadiri, J. A. Chem. SOC.,1995, 117, hydrogen-bondmg groups, formed a polymer. 12364 Extended structures can thus be designed with 58 C. M. Huwe and S. Blechert, Syntbedr, 1997,61 organoplatinum complexes via hydrogen bonding.

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