Factors influencing catalytic behavior of titanium complexes bearing bisphenolate ligands toward ring-opening polymerization of L -lactide and ε-caprolactone

eXPRESS Polymer Letters

M-T. Jiang¹ 

关键词: biodegradable polymers;    polycaprolactone;    ring-opening polymerization;    polylactide;   

DOI  :  10.3144/expresspolymlett.2018.11

学科分类：生物科学（综合）

来源: eXPRESS Polymer Letters

【 摘 要 】

A series of titanium complexes bearing substituted diphenolate ligands (RCH(phenolate)2, where R = H, CH3,o-OTs-phenyl, o-F-phenyl, o-OMe-phenyl, 2,4-OMe-phenyl) was synthesized and studied as catalysts for the ring openingpolymerization of L-lactide and ε-caprolactone. Ligands were designed to probe the role of chelate effect and steric effectin the catalytic performance. From the structure of triphenolate (with one extra coordination site than diphenolate ligand) Ticomplex, TriOTiOiPr2, we found no additional chelation to influence the catalytic activity of Ti complexes. It was foundthat bulky aryl groups in the diphenolate ligands decreased the rate of polymerization most. We conclude that steric effectis the most controlling factor in these polymerization reactions by using Ti complexes bearing diphenolate ligands as catalystssince it is responsible for the exclusion of needed space for incoming monomer by the bulky substituents on the catalyst.

【 授权许可】

CC BY