NOVEL GENERATION OF ORGANOMETALLIC SYSTEMS - METAL-CARBONYL-COMPLEXESWITH SILACARBACYCLIC PI-LIGANDS, SYNTHETIC AND STRUCTURAL INVESTIGATIONS

This review deals with the preparation and structure investigation of metal carbonyl (Cr, Mo, W, Fe) complexes with 9,10-disiladihydroanthra cene (I), 9-silafluorene (II), 9-oxa-10-siladihydrophenanthrene (III), 1-silaacenaphthene (IV), 1-silaphenalene (V) and 1-silacyclohexa-2,4- diene (VI) pi-ligands. Some questions concerning the regio- and stereo -regularities of eta-coordination are considered. The most interesting properties and structural peculiarities of the new complexes are summ arized: the relationship between the nature of the substituent in the sila-unit and the chemical behaviour of the complexes; the dependence of the silacycle conformation on substitution and coordination factors ; the specific arrangement of M(CO)(n)-fragments in crystals. (C) 1997 Elsevier Science S.A.