Imino(phenoxide) compounds of magnesium: Synthesis, structural characterization, and polymerization studies

A plethora of magnesium compounds containing imino(phenoxide) (1–4) and bis(imino)phenoxide (5–10) ligand backbone have been synthesized via the reaction of diethyl magnesium with two equivalent of the corresponding ligand. These compounds were completely characterized by different spectroscopic techniques and elemental analyses. The monomeric nature of the magnesium complexes 3, 5, 6, 9, and 10 were further confirmed by single crystal X-ray diffraction studies. The magnesium centers posses distorted trigonal bipyramidal geometry. The controlled hydrolysis compound Mg7O8 (C22H28NO2)6 (11) was adequately characterized using 1H, 13C NMR, ESI-MS, and the biscubane structure was further confirmed by single crystal X-ray diffraction studies. The Mg7O8 core is deeply embedded with the ligand periphery. These compounds (1–10) were found to be active towards the bulk ring opening polymerization (ROP) of lactides, yielding polymers with high number average molecular weight (Mn) and controlled molecular weight distributions (MWDs). In addition, these compounds have been shown to be highly active toward the copolymerization of carbon dioxide with cyclohexene oxide and styrene oxide. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1474–1491