Bis(μ-silylene)-Bridged Dinuclear Rhodium(0) Complex and Its Palladium(0) and Platinum(0) Analogues. Theoretical Study of Their Electronic Structure, Bonding Nature, and Interconversion between μ-Disilene-Bridged Form and Bis(μ-silylene)-Bridged Form

Abstract

The dinuclear rhodium(0) complex with composition Rh2(Si2H4)(PH3)4 is characterized as a bis(μ-silylene)-bridged dinuclear rhodium(0) complex with a Rh−Rh σ-bond, Rh2(μ-SiH2)2(PH3)4. In this complex, two d orbitals of one Rh center participate in the bonding interactions with the dσ orbital of the other Rh center and the occupied sp2 and unoccupied p orbitals of SiH2. The palladium(0) analogue is characterized as a μ-disilene-bridged dinuclear complex with a SiSi double bond and no Pd−Pd σ-bond, Pd2(μ-Si2H4)(PH3)4. On the other hand, the platinum(0) analogue is understood to be the bis(μ-silylene)-bridged dinuclear complex with a weak Si−Si bonding interaction, Pt2(μ-SiH2)2(PH3)4. It is theoretically proposed here that the interconversion between the bis(μ-silylene)-bridged form and the μ-disilene-bridged form is electrochemically achieved in the rhodium complex and that the palladium(0) and platinum(0) complexes, Pd2(μ-Si2H4)(PH3)4 and Pt2(μ-SiH2)2(PH3)4, are converted to the bis(μ-silylene)-bridged form...