Five-Coordinate Dihydridosilyl Platinum(IV) Complexes Supported by a Chelating Monoanionic Nitrogen-Based Ligand

Complexes of Pt(IV) containing the bidentate ligand 3,5-diphenyl-2-(2-pyridyl)pyrrolide (PyPyr) were prepared. The ethylene complex PyPyrPt(C2H4)Cl (1) was treated with HSiEt3 or HSiEtMe2 to produce the Pt(IV) silyl dihydrides PyPyrPt(H)2SiEt3 (3) and PyPyrPt(H)2SiEtMe2 (4), respectively. The solid-state structure of 3, determined by X-ray crystallography, reveals a dimeric structure that forms via π-stacking between the PyPyr ligands. Addition of Lewis bases to 3 results in either coordination to generate an octahedral Lewis base adduct (with DMAP) or silane elimination to give square-planar Pt(II) Lewis base complexes (with phosphines). Complex 3 was also found to be an active hydrosilylation catalyst for the hydrosilylation of alkynes and terminal olefins with HSiEt3.