环状聚酯的合成：水杨醛亚胺锡（II）配合物中烷氧基侧链的影响

Synthesis of cyclic polyesters: effects of alkoxy side chains in salicylaldiminato tin(II) complexes.

作者信息

Wongmahasirikun Phonpimon, Prom-on Paweenuch, Sangtrirutnugul Preeyanuch, Kongsaeree Palangpon, Phomphrai Khamphee

机构信息

Center for Catalysis, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand.

出版信息

Dalton Trans. 2015 Jul 21;44(27):12357-64. doi: 10.1039/c5dt00139k.

DOI:10.1039/c5dt00139k

PMID:25757191

Abstract

A new class of salicylaldiminato tin(II) catalysts having different alkoxy side chains has been developed. The ligands were modified to have different lengths and flexibilities such as –(CH2)2– (2a), –(CH2)3– (2b), –(ortho-C6H4)CH2– (2c) and –(CH2)2–O–(CH2)2– (2d). Complexes 2a, b were characterized crystallographically revealing a more constrained environment around the metal in complex 2a. These catalysts are active for the solvent-free polymerization of L-lactide and ε-caprolactone. Complex 2a having a shorter side chain was shown to better promote intramolecular transesterification affording cyclic polylactides and cyclic poly(ε-caprolactone). Complexes 2b and 2d having longer side chains produced cyclic poly(ε-caprolactone) as a major product but failed to give cyclic polylactides.

摘要

已开发出一类具有不同烷氧基侧链的新型水杨醛亚胺锡（II）催化剂。对配体进行了修饰，使其具有不同的长度和柔韧性，例如–(CH2)2– (2a)、–(CH2)3– (2b)、–(邻位-C6H4)CH2– (2c) 和–(CH2)2–O–(CH2)2– (2d)。通过晶体学对配合物2a、b进行了表征，结果表明配合物2a中金属周围的环境更加受限。这些催化剂对L-丙交酯和ε-己内酯的无溶剂聚合具有活性。具有较短侧链的配合物2a显示出能更好地促进分子内酯交换反应，生成环状聚丙交酯和环状聚（ε-己内酯）。具有较长侧链的配合物2b和2d以环状聚（ε-己内酯）作为主要产物，但未能生成环状聚丙交酯。