Carbonylative polymerization of oxetanes initiated by acetyl cobalt complexes.
Four acetyl cobalt complexes, [AcCo(CO)(3)P(p-tolyl)(3)] (1; p-tolyl=4-Me-C(6)H(4)), [AcCo(CO)(3)P(OPh)(3)] (2), [AcCo(CO)(3)P(NMe(2))(3)] (3), and [AcCo(CO)(2)(dppp)] (4; dppp=1,3-bis(diphenylphosphanyl)propane), were synthesized, characterized, and examined as catalysts for the unprecedented carbonylative polymerization of oxetanes. Copolymers containing ester (4-hydroxyalkanoate) and/or ether units were obtained with complexes 1 and 2, but not with complexes 3 and 4 either in the presence or absence of additional phosphorus ligands. The ester unit/ether unit ratio varied in the range 21:79-63:37, and the highest ester/ether ratio of 63:37 was achieved by using complex 1 in the presence of a further 5 equivalents of P(OPh)(3). Although direct carbonylative polymerization is possible, preformation and ring opening of the gamma-lactone is also suggested as an alternative pathway.
Permana
Yessi
Y
Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Nakano
Koji
K
Yamashita
Makoto
M
Watanabe
Daisuke
D
Nozaki
Kyoko
K
D002244:Carbon / Q000737:chemistry*; D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D004988:Ethers, Cyclic / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D011108:Polymers / Q000138:chemical synthesis*
D004988:Ethers, Cyclic; D011108:Polymers; D003035:Cobalt; D002244:Carbon; C005287:oxetane