Bis-Salicylaldiminato Complexes of Zinc. Examination of the Catalyzed Epoxide/CO2 Copolymerization

A series of salicylaldimine ligands of the general formula (NR2C7H5-x(R1)xOH) [x = 1 or 2; R1 = Me, tBu, Cl, OMe; R2 = 2,6-iPr2C6H3, or 3,5-(CF3)2C6H3] have been synthesized and characterized via 1H and 13C NMR, elemental analysis, and X-ray crystallography. The concomitant series of zinc bis(salicylaldiminato) complexes of the general formula have been synthesized and characterized in the solid state by X-ray crystallography. All complexes crystallized as four coordinate monomers with distorted tetrahedral geometry about the zinc center. The O−Zn−O angles range between 105 and 112.5°, and the N−Zn−N bond angles were more obtuse spanning the range 122.9−128.9°. The only deviation from distorted tetrahedral geometry occurred when R2 = 3,5-(CF3)2C6H3 which crystallized as a distorted trigonal bipyramidal dimeric species with Oax−Zn−Oax bond angles of 165.00(15)°. The equatorial angles approach 120° except for the Neq−Zn−Neq angle of 110.54(16)° which is attributed to the strain of the bridging ligands. The ...