Pentacoordinated tetraorganotin and silicon compounds—synthesis and structures

Abstract

Starting from di- and trifunctional Grignard reagents of the general types E(CH2CH2CH2MgCl)2 (E= NMet0, S) and N(CH2CH2CH2MgCl)3 the cyclic organotin and organosilicon compounds R2M(CH2CH2CH2andRM(CH2CH2CH2)3N (M= SifSn; R= Cl, Br, I, CH3) are described. X-ray studies confirm these compounds to exhibit pentacoordinated structures with intramolecular donor-acceptor interactions. The strength of these interactions depends from the nature of the substituents bonded to the metal center. The dynamic processes which are observed by nmr investigations are interpreted in terms of a dissociation-inversion mechanism and an “in-out” equilibrium. First results are reported concerning the preparation of a two nitrogen containing difunctional Grignard reagent and its reaction with tin tetrachloride providing hexacoordinated tin compounds. © 1986 IUPAC