Exploring the reactivity of homoleptic organozincs towards SO2: synthesis and structure of a homologous series of organozinc sulfinates.

Abstract

Studies on the reactivity of zinc alkyl compounds towards SO2 are relatively less explored than either oxygenation or hydrolysis reactions. We report on the environmentally friendly and efficient syntheses of a homologous series of [(RSO2)ZnR]n complexes from reactions involving homoleptic R2Zn (R = Me, tBu, Ph) compounds and SO2. Diffusion ordered spectroscopy experiments indicate that the resulting compounds predominately occur as solvated dimers, [(RSO2)ZnR(THF)]2, in THF solution irrespective of the character of the group bonded to the zinc centres. In turn, these organozinc sulfinates exhibit structurally diversified molecular and supramolecular arrangements in the solid state, as evidenced by single-crystal X-ray diffraction studies. The methyl compound crystallises as a one-dimensional polymer, [(MeSO2)ZnMe]n, and the use of tBu2Zn and Ph2Zn leads to molecular aggregates, a tetramer [(tBuSO2)ZntBu]4, and a solvated [(PhSO2)ZnPh]2·2THF dimer, respectively. In addition, new theoretical insights have been gained by modelling the direct trapping of homoleptic organozinc compounds with SO2 using DFT calculations.