Carbon Dioxide Copolymerization Study with a Sterically Encumbering Naphthalene-Derived Oxide
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2015 American Chemical Society. Poly(1,4-dihydronaphthalene carbonate) has been prepared via the catalytic coupling of carbon dioxide and 1,4-dihydronaphthalene oxide using chromium(III) catalysts. The copolymer formation is found to be greatly dependent on the steric environment around the metal center. Traditional (salen)CrIIIX/cocatalyst systems bearing bulky t-butyl groups hinder the approach of the large monomer, significantly diminishing polymer chain growth and providing the entropically favored cyclic byproduct in excess. In contrast, employing the sterically unencumbered azaannulene-derived catalyst, (tmtaa)CrIIIX/cocatalyst system (tmtaa = tetramethyltetraazaannulene) shows polymer selectivity close to 90% with three times the activity (TOF = 20-30 h-1). With the use of a bifunctional (salen)CrIII catalyst, even higher polymer selectivity (>90%) can be observed. The complete synthesis of a new bifunctional tetraazaannulene ligand for a more effective catalyst is also described herein.
author list (cited authors)
Darensbourg, D. J., & Kyran, S. J.
complete list of authors
Darensbourg, Donald J||Kyran, Samuel J