Gallium and indium complexes containing the bis(imino)phenoxide ligand: synthesis, structural characterization and polymerization studiesElectronic supplementary information (ESI) available: NMR and mass spectra of the reported compounds. CCDC 1048007 (2), 1048008 (4) and 1048009 (9). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5dt00811e

• Main Authors: Ghosh, Swarup, Gowda, Ravikumar R, Jagan, Rajamony, Chakraborty, Debashis
• Format: Journal Article
• Language: English
• Published: 27.05.2015
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c5dt00811e

A series of gallium and indium complexes containing a bis(imino)phenolate ligand framework were synthesized and completely characterized with different spectroscopic techniques. The molecular structures of a few complexes were determined using single crystal X-ray diffraction studies. These compounds were found to be extremely active towards the bulk ring opening polymerization (ROP) of lactides yielding polymers with high number average molecular weight ( M n ) and controlled molecular weight distributions (MWDs). The neutral complexes 1-8 produce isotactic enriched poly(lactic acid) (PLA) from rac -lactide ( rac -LA) under melt conditions, whereas the ionic complex 9 produces atactic PLA. The polymerizations are controlled, as evidenced by the narrow molecular distribution (MWDs) of the isolated polymers in addition to the linear nature of number average molecular weight ( M n ) versus conversion plots with variations in monomer to catalyst ratios. The kinetic and mechanistic studies associated with these polymerizations have been performed. A series of gallium and indium complexes containing the bis(imino)phenolate ligand framework were synthesized and completely characterized with different spectroscopic techniques.