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Mechanistic Studies of Cyclohexene Oxide/CO 2 Copolymerization by a Chromium(III) Pyridylamine‐Bis(Phenolate) Complex
Author(s) -
DevainePressing Katalin,
Kozak Christopher M.
Publication year - 2017
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201601641
Subject(s) - cyclohexene oxide , nucleophile , chemistry , catalysis , epoxide , polymer chemistry , cyclohexene , chromium , oxide , ligand (biochemistry) , copolymer , polymerization , ether , ring opening polymerization , medicinal chemistry , organic chemistry , polymer , biochemistry , receptor
Chromium(III) chlorido amine‐bis(phenolate) complexes paired with nucleophilic co‐catalysts are a promising family of catalysts for the copolymerization of CO 2 and epoxides to selectively produce polycarbonates with a very high degree of carbonate linkages. Single‐component catalyst systems can be prepared, where the neutral nucleophile, 4‐dimethylaminopyridine (DMAP), is coordinated to the metal site to provide a stable octahedral Cr III complex. These complexes possess the potential for both anionic (from the chlorido ligand) or neutral (DMAP) nucleophilic epoxide ring‐opening during the proposed rate‐determining initiation step. Concentration effect studies support a first‐order dependence of the polymerization rate on the concentration of single‐component catalyst. End‐group analysis of polycarbonates by MALDI‐TOF MS indicate the presence of predominantly DMAP‐initiated chains as well as the occurrence of chain‐transfer events resulting in ether linkages, likely from the presence of cyclohexene diol formed by the reaction of cyclohexene oxide and adventitious water.