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could effectively stabilise co-ordinatively unsaturated platinum and rhodium complexes which had high nucleophilic reactivity towards small molecules. A number of examples were presented including the production of hydrogen from water by a rhodium complex.

Professor M. A. Bennett of the Australian National University, Canberra, then discussed the chemistry of arene ruthenium(I1) complexes which could be reduced under mild conditions in the presence of an olefin. Protonation of the resulting ruthenium(o) arene-olefin complexes gave monohydrido ruthenium(I1) salts which, in solution, were fluxional with the hydrogen migrating between metal and olefin.

Ring systems formed by amine attack on olefins co-ordinated to platinum(I1) formed the subject of a paper by Professor B. L. Shaw and three of his colleagues at the University of Leeds. Variation of the amine and olefin gave rise to either four or eight membered ring cyclic complexes or to binuclear platinum complexes with two rrans-fused five-membered rings.

New compounds of ruthenium and osmium containing the dichlorocarbene ligand were reported on by. Dr. W. R. Roper of the University of Auckland, New Zealand, while a paper from Professor M. F. Lappert and his colleagues in the School of Chemistry at Sussex University described a series of stable o- halogenoalkyls of platinum and amides of rhodium and iridium.

Homogeneous Catalysis

Professor P. M. Maitlis of the University of Sheffield contributed a paper on new types of homogeneous catalytic reactions with the half- sandwich complexes of the platinum metals. Reactions that had been investigated included olefin hydrogenation and carbonyl and arene hydrogenation, while hydrogen transfer reac- tions were found to be well promoted. Novel aldehyde disproportionation reactions offering a useful route to ethanol and acetic acid were described, using rhodium and ruthenium-com- plexes, while some new rhodium and iridium complexes provide an insight into the mechanism of the Fisher-Tropsch reaction.

Platinum Metals Rev., 1981, 25, (4)

A remarkable performance by Professor B. M. Trost of the University of Wisconsin opened the discussions on organic synthesis and homogeneous catalysis. His main conference lecture, on organopalladium intermediates as chemical chameleons, had the underlying theme that olefins may be activated by formation of an intermediate palladium z-ally1 complex which can subsequently be attacked by a variety of nuckophiles. The reactions discussed were highly regio- and stereoselective and were used to prepare a wide range of products of biological interest ranging from insect pheromones to precursors for macrolide antibiotics and prostaglandins. Professor Trost also described a novel approach to the synthesis of five-membered carbocyclic rings by reaction of an olefin with the palladium complex of trimethylenemethane.

The study of the mechanisms by which platinum metal complexes catalyse organic reactions and of the application of these processes in selective organic synthesis formed the subject of a paper by Dr. J. M. Brown of the Dyson Perrins Laboratory in the University of Oxford. These factors were illustrated by work on homogeneous hydrogenation employing cationic rhodium complexes in aprotic solvents. The mechanism of the industrially important rhodium complex catalysed hydroformylation process was studied and shown to be a highly complex system with many stable states accessible.

Professor W. Keim of the Institut fur Technische Chemie, Aachen, discussed his recent work on the telomerisation of isoprene with water or ammonia using homogeneous palladium catalysts. This offers an attractive route to commercially important terpenoid compounds but is complicated by the large number of possible products, although the selectivity could be improved by variation of the phosphine ligand or addition of acid.

Professor B. K. James of the University of British Columbia described some aspects of the chemistry of ruthenium porphyrin complexes, including a system for the catalytic decar- bonvlation of aldehydes which was proposed to


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