Pentacoordinate hydrochlorosilanes with lactamomethyl ligand

The synthesis and reaction behavior of pentacoordinate hydrochlorosilanes LCH2SiRHCl (L- 2-piperidonyl ligand, R = Me, Ph, Bn) are described. The intramolecular O–Si and N–Si coordination is discussed on the basis of the NMR data. The strength of the O–Si coordinate bond is nearly the same for chelates 5, 6, 8 irrespective of the equatorial substituent R at the silicon atom. However, the nature of R substituent markedly affects the stability of the complexes with the N–Si intramolecular bond.