title: Synthesis of Copolymers by Living Carbanionic Alternating Copolymerization.
abstract: The synthesis and characterization of copolymers from styrene and 1,3-pentadiene (two isomers) are reported. Styrene/1,3-pentadiene (1:1) copolymerization with carbanion initiator yield living, well-defined, alternating (r1 = 0.037, r2 = 0.056), and highly stereoregular copolymers with 90%-100% trans-1,4 units, designed Mn s and low ÐM s (1.07-1.17). The first-order kinetic resolution and NMR spectra demonstrate that the copolymers obtained possess strictly alternating structure containing both 1,4- and 4,1-enchaiments. Also a series of copolymers with varying degrees of alternation are synthesized from para-alkyl substituted styrene derivatives and 1,3-pentadiene. The degree of alternation is strongly dependent on the polarity of solvent, reaction temperature, type of trans-cis isomer of 1,3-pentadiene and para-substituted group in styrene. The macro zwitterion forms (SPC) through the distribution of electronic charges from the donor (1,3-pentadiene) to the acceptor (styrenes) are proposed to interpret the carbanion alternating copolymerization mechanism. Owing to the versatility of the carbanion-initiating reaction, the present alternating strategy based on 1,3-pentadiene (especially cis isomer) can serve as a powerful tool for precise control of polymer chain microstructure, architecture, and functionalities in one-pot polymerization.
authors.affiliation: Country State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.affiliation: Country State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.
authors.forename: Lei
authors.initials: L
authors.lastname: Ren
authors.affiliation: Country State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.
authors.forename: Qing
authors.initials: Q
authors.lastname: He
authors.affiliation: Country State Key Laboratory for Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, P. R. China.
authors.forename: Wei Jian
authors.initials: WJ
authors.lastname: Xu
mesh_terms: D000466:Alkadienes / Q000737:chemistry*; D010420:Pentanes / Q000737:chemistry*; D011137:Polystyrenes / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D000466:Alkadienes; D010420:Pentanes; D011137:Polystyrenes; C011970:1,3-pentadiene
keywords: 1,3-pentadiene; carbanionic alternating copolymerization; stereoregular; zwitterion forms