Phonpimon WongmahasirikunPaweenuch Prom-onPreeyanuch SangtrirutnugulPalangpon KongsaereeKhamphee PhomphraiMahidol UniversityPTT2018-11-232018-11-232015-07-21Dalton Transactions. Vol.44, No.27 (2015), 12357-1236414779234147792262-s2.0-84939235538https://repository.li.mahidol.ac.th/handle/123456789/35743© The Royal Society of Chemistry 2015. 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.Mahidol UniversityChemistryArticleSCOPUS10.1039/c5dt00139k