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

Dinuclear palladium complexes with two bridging diphenylsilyl ligands, [(Me 3 P)Pd( μ-SiHPh 2 )] 2 ( 1 ) and (Me 3 P)Pd(μ-SiHPh 2 ) 2 Pd(PMe 3 ) 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-SiHPh 2 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 1 H and 31 P{ 1 H} 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.