Copolymerization of CO2 and cyclohexene oxide: β-diketiminate-supported Zn(II)OMe and Zn(II)Et complexes as initiators

Article abstract of DOI:10.1021/om400977c

β-Diketiminate ligands with varying degrees of steric bulkiness and having -CN and -NO₂ groups on N-aryl substituents were synthesized. The catalytic activity of some of their [LZnEt] and [LZnOMe]₂ complexes (L = β-diketiminato) toward the copolymerization of carbon dioxide and cyclohexene oxide was explored. All the catalysts were found to be highly active and showed very good turnover frequency, and the polycarbonates produced have a very high percentage of carbonate linkages. The complex [L ^iPr,Me-CNZnEt] showed very high activity and selectivity on par with its zinc methoxide analogue. The polymers produced by [LZnEt] complexes displayed a bimodal molecular weight distribution.