Unprecedented solvent induced inter-conversion between monomeric and dimeric silylene–zinc iodide adducts

Abstract

Usually, when a silylene reacts with a transition metal Lewis acid, it forms an adduct which could be either monomeric or dimeric. However, we present here that a silylene, [PhC(NtBu)₂SiN(SiMe₃)₂] can form both monomeric [PhC(NtBu)₂Si{N(SiMe₃)₂} → ZnI₂]·THF (1) and dimeric [{PhC(NtBu)₂}(N(SiMe₃)₂)SiZnI,(μ-I)]₂ (2) adducts upon reaction with ZnI₂. The formation of 1 and 2 relies upon the solvent used for the reaction or crystallization. When the crystallization is carried out in THF complex 1 is formed, however, when the reaction and crystallization are performed in acetonitrile complex 2 is obtained. Both 1 and 2 were structurally authenticated and the nature of the Si–Zn bond in these complexes was determined by quantum chemical calculations. In addition, a spontaneous inter-conversion between 1 and 2 just by changing the solvents has been also observed; a feature presently not known for silylene-transition metal Lewis adducts.