title: Carbonylative polymerization of oxetanes initiated by acetyl cobalt complexes.
abstract: 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.
authors.affiliation: Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Yessi
authors.initials: Y
authors.lastname: Permana
authors.forename: Koji
authors.initials: K
authors.lastname: Nakano
authors.forename: Makoto
authors.initials: M
authors.lastname: Yamashita
authors.forename: Daisuke
authors.initials: D
authors.lastname: Watanabe
authors.forename: Kyoko
authors.initials: K
authors.lastname: Nozaki
mesh_terms: 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*
chemical_list: D004988:Ethers, Cyclic; D011108:Polymers; D003035:Cobalt; D002244:Carbon; C005287:oxetane