Reactions of a novel quadruply chelated molybdenum-silyl complex with beta-dicarbonyl compounds

The novel molybdenum-silyl complex [MoH3{[Ph2PCH2CH2P(Ph)-C6H4-o](2)(Ar)Si- P,P,P,P,Si}] (1) reacted with 2,4-pentanedione to give eight-coordinate dih ydrido complex 2 (a, Ar = Ph; b, Ar = o-tolyl) with a chelated 2,4-pentaned ionato ligand as a result of repelling one of four Mo-P bonds in 1. On the other hand, the reaction between 1 and dialkyl malonates gave an eta(1)-O-e nolato type complex in which the quadruply chelated P-P-Si-P-P framework wa s found to be kept intact. The structure of 2a was confirmed by X-ray cryst allographic structure analysis. (C) 2000 Elsevier Science S.A. All rights r eserved.