Palladium−Platinum Heterobimetallic Complexes with Bridging Silicon Ligands. Structure and Reaction with Isonitrile to Afford a Platinacyclopentane Containing Si, N, and C Atoms

The reaction of Pt(SiHPh2)2(PEt3)2 with Pd(PEt3)3 produced heterodinuclear complexes
with bridging diphenylsilyl ligands (Et3P)Pt(μ-η2-SiHPh2)2Pd(PEt3) (1) and (Et3P)2Pt(μ-η2-SiHPh2)2Pd(PEt3) (2). Each product was isolated and fully characterized. X-ray
crystallography of 2 and NMR spectra of 2 and 2-d2 at 25 °C indicated the presence of two
bridging SiHPh2 (or SiDPh2) ligands, which were bonded to one metal center via a M−Si
single bond and to the other via a Si−H−M three-center, two-electron bond. The 1H NMR
spectrum of 2 at −90 °C exhibited a peak at δ −8.61 due to a hydrido ligand bonded to the
Pt center, indicating the structure (Et3P)2PtH(μ-SiPh2)(μ-η2-SiHPh2)Pd(PEt3) in the solution
at low temperature. Complex 2 reacted with CN-t-Bu to form a mixture of (3) and [(Et3P)(t-BuNC)Pt(μ-SiPh2)]2 (4). Complex 3 contained
the platinacyclopentane group, whose five-membered ring was composed of Pt, Si, N, and C
atoms.