Reactions of a novel quadruply chelated molybdenum–silyl complex with β-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 dihydrido complex 2 (a, Ar=Ph; b, Ar=o-tolyl) with a chelated 2,4-pentanedionato 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 η1-O-enolato type complex in which the quadruply chelated P–P–Si–P–P framework was found to be kept intact. The structure of 2a was confirmed by X-ray crystallographic structure analysis.