Abstract: Synthetic polymers find widespread applications in our daily life.1 To date, the production of most commercial plastic materials relies upon petroleum derived feedstock as the starting raw material. The disadvantage of petroleum feedstock is that they are non-renewable, and the plastics derived from them do not degrade quickly, adding further waste to the planet. Thus, there has been increasing research endeavors for synthesizing environmentally benign materials, the raw materials for which are fully or partially derived from renewable feedstocks.2 The three classes of oxygenated polymers, namely polyethers, aliphatic polyesters, and aliphatic polycarbonates, have drawn the interest of researchers worldwide to serve as alternatives to fossil-fuel derived polymers. The abovementioned oxygenated polymers can be synthesized by chain-growth polymerization compared to the conventional polycondensation pathway, which requires drastic reaction conditions. The chain- growth polymerization can be catalyzed by simple metal initiators, metal compounds supported by ancillary ligands and organocatalysts.3
In our study, we used Group 13 metal initiators for the homopolymerization of epoxides. The phenoxy-imine based Group 13 and Group 4 metal compounds were synthesized and thoroughly characterized by spectroscopic techniques and single-crystal X-ray diffraction. The catalytic activity of the metal compounds was investigated for the ring-opening polymerization (ROP) of cyclic esters and ring-opening copolymerization (ROCOP) of epoxide and anhydride and epoxide with CO2. The catalytic activity is correlated to the steric and electronic environment of the ancillary ligand attached to the metal center. The polymers obtained were characterized by gel permeation chromatography (GPC), thermal studies, and the microstructure of the polymer chain was determined through NMR spectroscopy. In addition, we also explored the catalytic activity of benzoxazine based bimetallic Al(III) compounds.4
References: 1. Namazi, H. BioImpacts 2017, 7, 7374. 2. Bachmann, M.; Katelhon, A.; Winter, B.; Meys, R.; Muller, L. J.; Bardow, A. Faraday discuss. 2021, 230, 227246. 3. Roy, S. S.; Sarkar, S.; Chakraborty, D. J. Inclusion Phenom. Macrocyclic Chem. 2021, 100, 136. 4. Roy, S. S.; Sarkar, S.; Antharjanam, P. K. S.; Chakraborty, D. Eur. J. Org. Chem. 2023, 26, e202300371.