Synthesis of heterodinuclear hydride complexes by oxidative addition of a transition-metal hydride to Pt(0) and Pd(0) complexes

Abstract

Heterodinuclear hydridoplatinum and -palladium complexes, (dppe)HPt–MLn (MLn = MoCp(CO)3 (3a), WCp(CO)3 (3b)), (dppe)Pt(μ-H)(μ-CO)Mn(CO)4 (3c), (dppe)Pt(μ-H)(μ-CO)FeCp(CO) (3d), cis-L′2HPt–MLn (5aa: Lʹ = PPh3; MLn = MoCp(CO)3, 5ba: Lʹ = PPh3; MLn = WCp(CO)3, 5ab: Lʹ = PMePh2; MLn = MoCp(CO)3, 5ac: Lʹ = PMe2Ph; MLn = MoCp(CO)3), (dppe)Pd(μ-H)(μ-CO)MLn (MLn = MoCp(CO)2 (7a), WCp(CO)2 (7b)), (dppe)Pd(μ-H)(μ-CO)Mn(CO)4 (7c) are prepared by the oxidative addition of mononuclear transition-metal hydride complexes to zero-valent platinum or palladium complexes. The reactions of the heterodinuclear hydride complexes 3a, 3d and 7a with electron deficient alkenes and alkynes such as dimethyl fumarate or DMAD cause reductive elimination at the Pt or Pd center to give the Pt(alkene or alkyne)(dppe) and MHLn,, suggesting reversibility of this process. The DFT calculations suggest that these reactions are controlled by the thermodynamic stability and the electron rich alkene complex of Pt(0) (or Pd(0)) are preferable to prepare these heterodinuclear hydride complexes by the oxidative addition.