Titanium complexes bearing 2,6-Bis(o-hydroxyalkyl)pyridine ligands in the ring-opening polymerization of L-Lactide and ε-caprolactone
| Autor: | Chien-Chih Chiu, Feng Jie Lai, Kuo Hui Wu, Wei Yi Lu, Tsai Wen Huang, Heng Yi Chang, Hsuan-Ying Chen, Yu Lun Chang, Shangwu Ding |
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| Rok vydání: | 2020 |
| Předmět: |
Steric effects
Polymers and Plastics Organic Chemistry 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology Ring (chemistry) 01 natural sciences Medicinal chemistry Ring-opening polymerization 0104 chemical sciences chemistry.chemical_compound chemistry Polymerization Pyridine Materials Chemistry Hydroxymethyl 0210 nano-technology Caprolactone Isopropyl |
| Zdroj: | Polymer. 204:122860 |
| ISSN: | 0032-3861 |
| DOI: | 10.1016/j.polymer.2020.122860 |
| Popis: | A series of titanium (Ti) compounds bearing 2,6-bis(o-hydroxyalkyl)pyridine ligands were synthesized and investigated as catalysts for the ring-opening polymerization of e-caprolactone (CL) and L-lactide (LA). The Ti complexes with electron-withdrawing groups in pyridine rings or steric bulky groups in hydroxymethyl groups reduced the catalytic activity in CL and LA polymerizations, and MeLPh-TiOPr2 exhibited the highest catalytic activity ([CL] = 0.5 M, [CL]:[Cat] = 100:8, 60 °C, 7.5 h, conversion = 93%; [LA] = 0.5 M, [LA]:[Cat] = 100:8, 60 °C, 3.5 h, conversion = 98%). The density functional theory calculation results revealed that CL interacted with the ligand through weak hydrogen bonds, and then approached the Ti center. After being attacked by isopropyl oxide, the carbonyl group of CL bonded to the Ti center. After the rearrangement and ring opening of CL ring, CL was converted to poly-e-caprolactone. |
| Databáze: | OpenAIRE |
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