Di-Zinc–Aryl Complexes: CO2 Insertions and Applications in Polymerisation Catalysis

5 years ago

Di-Zinc–Aryl Complexes: CO2 Insertions and Applications in Polymerisation Catalysis

Charles Romain, Jennifer A. Garden, Gemma Trott, Andrew J. P. White, Antoine Buchard, Charlotte K. Williams

Two new di-zinc–aryl complexes, [LZn2Ph2] and [LZn2(C6F5)2], coordinated by a diphenol tetraamine macrocyclic ligand have been prepared and fully characterised, including by single-crystal X-ray diffraction experiments. The complexes’ reactivities with monomers including carbon dioxide, cyclohexene oxide, phthalic anhydride, isopropanol and phenol were investigated using both experimental studies and density functional theory calculations. In particular, [LZn2Ph2] readily inserts carbon dioxide to form a carboxylate, at 1 bar pressure, whereas [LZn2(C6F5)2] does not react. Under these conditions [LZn2Ph2] shows moderate activity in the ring-opening copolymerisation of cyclohexene oxide/carbon dioxide (TOF=20 h−1), cyclohexene oxide/phthalic anhydride (TOF=33 h−1) and the ring-opening polymerisations of rac-lactide (TOF=99 h−1) and ϵ-caprolactone (TOF=5280 h−1). Versatile catalysis: Reactivity studies of zinc–aryl complexes towards carbon dioxide, alcohols, epoxides and anhydrides are investigated using a combination of experimental methods and density functional theory calculations. The catalyst systems are active for both ring-opening copolymerisation of epoxide with CO2 or anhydrides, and the ring-opening polymerisation of lactones.

Publisher URL: http://onlinelibrary.wiley.com/resolve/doi

DOI: 10.1002/chem.201701013