(Tetramethyltetraazaannulene)chromium Chloride: A Highly Active Catalyst for the Alternating Copolymerization of Epoxides and Carbon Dioxide

Autor: Shawn B. Fitch, Donald J. Darensbourg
Rok vydání: 2007
Předmět:
Zdroj: Inorganic Chemistry. 46:5474-5476
ISSN: 1520-510X
0020-1669
DOI: 10.1021/ic7007842
Popis: A tetramethyltetraazaannulene complex incorporating a chromium(III) metal center has been shown to be highly active toward the copolymerization of cyclohexene oxide and carbon dioxide to afford poly(cyclohexene carbonate) in the presence of [PPN]N3 [PPN+=bis(triphenylphosphoranylidene)ammonium] as a cocatalyst. An asymptotical rate increase was observed, leveling at 2 equiv of cocatalyst with a maximum turnover frequency of 1300 h(-1) at 80 degrees C. A benefit of this new catalyst system over that of the previously studied less-active (salen)CrX system is that the (tmtaa)CrCl catalyst has a much lower propensity toward the formation of a cyclic carbonate byproduct throughout the copolymerization reaction.
Databáze: OpenAIRE