Iron amino-bis(phenolate) complexes for the formation of organic carbonates from CO2and oxiranesElectronic supplementary information (ESI) available. CCDC 1452392and 1452393. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6cy00477f

A series of iron(iii) compounds supported by tetradentate amino-bis(phenolate) ligands were synthesized and characterized using electronic absorption spectroscopy, magnetic moment measurement and MALDI-TOF mass spectrometry. The solid-state structures of 1and 2were determined by X-ray diffraction and reveal iron(iii) square pyramidal compounds. The complexes were studied as catalysts for the reaction of carbon dioxide and epoxides in the presence of a co-catalyst, under solvent free conditions to yield cyclic carbonates. Catalytic testing with TBAB as a co-catalyst shows that 4bearing electron withdrawing groups in the orthoand para-positions of the phenolate ring exhibits the highest catalytic activity. Kinetic studies using 1revealed that the cycloaddition reaction is affected by temperature as expected and the activation energy for propylene carbonate formation is 98.4 kJ mol−1.