Towards Extended Zinc Ethylsulfinate Networks by Stepwise Insertion of Sulfur Dioxide into Zn-C Bonds.

The ability to utilize polluting gases in efficient metal-mediated transformations is one of the most pressing challenges of modern chemistry. Despite numerous studies on the insertion of SO2 into M-C bonds, the chemical reaction of SO2 with organozinc compounds remains little explored. To fill this gap, we report here the systematic study of the reaction of Et2 Zn towards SO2 as well as the influence of Lewis bases on the reaction course. Whereas the equimolar reaction provided a novel example of a structurally characterized organozinc ethylsulfinate compound of general formula [(EtSO2 )ZnEt]n , the utilization of an excess of SO2 led to the formation of the zinc(II) bis(ethylsulfinate) compound [(EtSO2 )2 Zn]n . Moreover, we have discovered that the presence of N-donor Lewis bases represents an efficient tool for the preparation of extended zinc ethylsulfinates, which in turn led to the formation of 1D [(EtSO2 ZnEt)2 (hmta)]n and 2D [((EtSO2 )2 Zn)2 (DABCO)]n ⋅solv (in which solv=THF or toluene, hmta= hexamethylenetetramine, and DABCO=1,4-diazabicyclo[2.2.2]octane) coordination polymers, respectively. The results of DFT calculations on the reactivity of SO2 towards selected Zn-C reactive species as well as the role of an N-donor Lewis base on the stabilization of the transition states complement the discussion.