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.