Macrocyclic vs. linear polymer formation in the coordination-insertion polymerization of cyclic carbonates

Abstract

Investigations on the mechanistic aspects of the coordination-insertion polymerization of six-membered cyclic carbonate 5,5-dimethyl-1,3-dioxan-2-one (DTC) initiated by tin(II) alkoxide-based catalysts are presented. 1H NMR and MALDI-TOF mass spectrometric analyses of the DTC polymerization products revealed that predominantly macrocyclic oligocarbonates are formed in the presence of a stannane catalyst. It was found that the addition of a small amount of water or diol suppresses the macrocyclization and linear polycarbonates can be obtained. The plausible mechanism of macrocyclization and linear product formation is proposed and discussed.