Chemical fixation of carbon dioxide catalyzed via cobalt (III) ONO pincer ligated complexes

Chemical insertion of carbon dioxide into epoxides under ambient conditions has become one of the most important methods for the construction of cyclic organic carbonates. Various active salen, salophen, and phenolate ligand based complexes have been reported for the synthesis of cyclic organic carbonates. Here we demonstrate a series of ONO pincer type cobalt (III) complexes as efficient catalysts for the cycloaddition of carbon dioxide to epoxides in neat conditions at atmospheric pressure with and without co-catalyst. A turnover number of up to 200,000 under atmospheric pressure is achieved. Moreover, the in situ generated complex shows high activity and the catalyst can be reused for at least 11 cycles without any decline in catalytic performance.