Ring-opening copolymerisation of cyclohexene oxide and carbon dioxide catalysed by scorpionate zinc complexes

A series of new acetate and trifluroacetate bimetallic zinc complexes containing heteroscorpionate ligands have been prepared in very high yields. The structures of the complexes were determined by spectroscopic methods, and the single-crystal X-ray structure of complex 6 confirmed a kappa(3)-NNO coordination mode of the scorpionate ligand in a dinuclear molecular arrangement. Bimetallic zinc complexes 6-11 were investigated as catalysts for the synthesis of polycarbonates from epoxides and carbon dioxide in the absence of a cocatalyst. Under the optimal reaction conditions, complex 10 acts as an efficient single-component initiator for the ring-opening copolymerisation of cyclohexene oxide and carbon dioxide, yielding polycarbonate materials with narrow polydispersities.