Reactivity of an amidinato silylene and germylene toward germanium(ii), tin(ii) and lead(ii) halides

Abstract

The coordination chemistry of an amidinato silylene and germylene toward group 14 element(II) halides is described. The reaction of the amidinato silicon(II) amide [LSiN(SiMe₃)₂] (1, L = PhC(NtBu)₂) with SnCl₂ and PbBr₂ afforded the amidinato silylene–dichlorostannylene and –dibromoplumbylene adducts [L{(Me₃Si)₂N}SiEX₂] (E = Sn, X = Cl (2); E = Pb, X = Br (3)), respectively, in which there is a lone pair of electrons on the Sn(II) and Pb(II) atoms. X-ray crystallography, NMR spectroscopy and theoretical studies show conclusively that the Si(II)–E(II) bonds are donor–acceptor interactions. Similar electronic structures were found in the amidinato germylene–dichlorogermylene and –dichlorostannylene adducts [L{(Me₃Si)₂N}GeECl₂] (E = Ge (5), Sn (6)), which were prepared by treatment of the amidinato germanium(II) amide [LGeN(SiMe₃)₂] (4) with GeCl₂·dioxane and SnCl₂, respectively.