Controlled ring‐opening polymerization of ε‐caprolactone initiated by in situ formed yttrium trisalicylaldimine complexes,and their study by density functional theory |
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| Authors: | Xufeng Ni Zhenhua Liang Jun Ling Xue Li Zhiquan Shen |
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| Affiliation: | MOE Key Laboratory of Macromolecular Synthesis and Functionalization, Department of Polymer Science and Engineering, Zhejiang University, Hangzhou 310027, China |
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| Abstract: | A series of yttrium trisalicylaldimine complexes formed in situ by the reaction of trialkyl complex [Y(CH2SiMe3)3(THF)2] (THF is tetrahydrofuran) with three equivalent salicylaldimines were used as initiators for the ring‐opening polymerization of ε‐caprolactone. Electronic and steric effects of the salicylaldimine ligand played important roles on the catalytic properties of the yttrium complexes. The yttrium trisalicylaldimine complex Y( L7 )3 ( L7 = (S)‐2,4‐di‐tert‐butyl‐6‐[(1‐phenylethylimino)methyl]phenol) most effectively initiated controlled ring‐opening polymerization of ε‐caprolactone to prepare poly(ε‐caprolactone)s with high molecular weights and moderate molecular weight distributions. Obtained by density functional theory calculations, the optimized geometries of the four different active centers with four salicylaldimine ligands explained the experimental results. Copyright © 2011 Society of Chemical Industry |
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| Keywords: | yttrium salicylaldimine complex catalysts DFT calculations ε ‐caprolactone ring‐opening polymerization |
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