Synthesis and characterization of the unstable primary amido tin(ii) dimer Sn2{N(H)Dipp}4 (Dipp = C6H3-2,6-Pri2) and the first sesqui-amido hemi-chloride derivative Sn2{N(H)Dipp}3Cl: facile conversion of a primary amide to the imide (SnNDipp)4

Abstract

The primary tin(ii) amido derivatives Sn(2){N(H)Dipp}(4) () and Sn(2){N(H)Dipp}(3)Cl () (Dipp = C(6)H(3)-2,6-Pr(i)(2)) have been prepared and characterized. Compound was obtained by the transamination of Sn{N(SiMe(3))(2)}(2) with H(2)NDipp in a 1 : 2 ratio or by the reaction of two equivalents of LiN(H)Dipp with SnCl(2). The attempted preparation of Sn(Cl){N(H)Dipp} by reaction of LiN(H)Dipp with SnCl(2) in a 1 : 1 ratio led to the isolation of the unique species Sn(2){N(H)Dipp}(3)Cl, which is the first example of a sesqui-amido derivative of a group 14 element. Both and were characterized by (1)H and (119)Sn NMR spectroscopy, X-ray crystallography and Mössbauer spectroscopy. The structures of and feature two tin centers bridged by -N(H)Dipp ligands with the terminal positions being occupied by two N(H)Dipp () or -N(H)Dipp and -Cl () groups. The compound was found to be unstable under ambient conditions and spontaneously converts to the imide tetramer (SnNDipp)(4) in solution over several days at room temperature, representing a new synthetic route to group 14 element imides.