Unsymmetrical and Symmetrical Dipalladium Complexes with Bridging Diphenylsilyl Ligands. Structures of (Me₃P)Pd(μ-SiHPh₂)₂Pd(PMe₃)₂ and [(Me₃P)Pd(μ-SiHPh₂)]₂ in the Solid State and in Solution

Abstract

Dinuclear palladium complexes with two bridging diphenylsilyl ligands, [(Me3P)Pd(μ-SiHPh2)]2 (1) and (Me3P)Pd(μ-SiHPh2)2Pd(PMe3)2 (2), were prepared and characterized by X-ray crystallography and NMR spectroscopy. The molecular structure of these complexes suggests an agostic interaction between H of μ-SiHPh2 and Pd. The symmetrical structure of 1 in solution is similar to that found in the crystals and is maintained in the temperature range +25 to −90 °C. The temperature-dependent 1H and 31P{1H} NMR spectra of 2 show dynamic behavior of the molecule caused by exchange of the phosphine ligands. The structure observed at −90 °C in the solution is similar to the crystallographic structure.