Platinum Metals Carbene Complexes Advances in Metal Carbene Chemistry, NATO AS1 Series, Volume 269 EDITED BY u. SCHUBERT, D. Reidel Publishing Co., Dordrecht, 1989, 407 pages, ISBN 0-7923-0156-0, Dfl. zoo.oo, U.S.$I 14.00, E64.00 This volume contains the proceedings of a New routes towards highly substituted NATO Advanced Research Workshop on cyclopentanoids via the metal-mediated cyclisa- Transition-Metal Carbene Complexes held at tion of alkynes and carbenes were reported by Wildbad Kreuth, West Germany in September J. M. O’Connor, L. Pu, J. A. Johnson and R. 1988. The 43 papers contained in this useful Uhrhammer, of the University of California at publication were contributed by lea* scien- San Diego. Stable iridium complexes contain- tists in the field. In eight of the chapters the ing both metallacycle and carbene ligands were complexes of the platinum group metals are the isolated, and on extended thermal decomposi- major topic, and a number of other authors tion these gave a mixture of products. A make peripheral references to platinum group rhodium metallacycle [RhCI(PPh,), metal complexes. The preponderance of papers (C,,O,H,,)l reacted with butynediol to give a dealing with early transition metals is a reflec- substituted anthraquinone rather than the tion both that the methodology developed for desired five membered ring. carbene synthesis by Professor E. 0. Fischer The synthesis of electron-rich alkenes con- and others is more readily applicable to these taining nitrogen functionalities attached to the metals, and also that in catalytic applications alkenic bond was discussed by J. A. Chamizo which invoke carbene complexes the use of ear- and M. F. Lappert of the University of Sussex. ly transition metals has predominated. Carbene complexes could be isolated when The conversion of carbynes to carbenes at these were reacted with palladium and rhodium heteronuclear dimetal centres was addressed by complexes. A further related contribution by F. G.A. Stone, of the University of Bristol. M. F. Lappert, P. B. Hitchcock and H. A. Bimetallic bridging carbynes were generated by Jasim of the University of Sussex, and B. the addition of organometallics, including com- Gtinkaya of Inonu University, Turkey con- plexes of platinum, rhodium and iridium, to cerned the synthesis of a range of rhodium tungsten carbynes. The protonation of the mix- carbene complexes and one iridium compound. ed metal carbyne was shown to generate a For these electron-rich carbenes, one carbene heterobimetallic bridging carbene complex, ligand was readily displaced from tRhCl(car- and platinum-tungsten systems appear par- bene),] by carbon monoxide or oxygen. ticularly useful in these transformations. The synthesis of cyclic and acyclic carbene The preparation of stable, methylene com- complexes of palladium(I1) and platinum(I1) plexes of iridium, osmium and ruthenium was derived from the reaction of aziridine, thiirane described by W. R. Roper of the University of and oxirane at co-ordinated isocyanide ligands Auckland. In the main, these were carried out was reported by R. Eertani, M. Mozzon, L. by the reaction of diazomethane with nitrosyl Zanotto and R. A. Michelin. Prehninary in- phosphine complexes. The resultant complexes vestigations of related polymer supported were characterised by crystallographic and carbene complexes were reported by B. Corain, spectroscopic means. For d* complexes it was R. A. Michelin, M. Mozzon and M. Zecca, also shown that the addition of electrophiles occur- of the University of Padua, Italy. red readily across the metal-carbon bond of the This volume provides a good guide to the carbene, whereas the d6 complexes were inert preparation of metal carbene complexes, and to electrophiles and unco-ordinated nucleo- will prove useful to those entering this area of philes, such as triphenylphosphineand pyridine. research. M.J.H.R. Platinum Metals Rev., 1989, 33, (3), 117 117 .