Chemical CO2 fixation using a cyanido bridged heterometallic Zn(ii)–Mn(ii) 2D coordination polymer

Abstract

A new cyanido bridged Zn(II)–Mn(II) mixed-metal coordination polymer, {[Zn(μ-L)(μ-CN)₂Mn_0.5]·(CH₃OH)}_n (1), has been synthesized by the reaction of Zn(CN)₂, Mn(II) salts and a hydrazone ligand (HL = (E)-N′-(phenyl(pyridin-2-yl)methylene)isonicotinohydrazide) in methanol. Compound 1 was characterized using various analytical methods (including elemental analysis, photoluminescence, FT-IR, XRD, SEM, and EDX analyses, and TGA), and its structure was determined by X-ray analysis. These analyses confirmed the formation of a mixed metal Zn(II)–Mn(II) coordination polymer containing both cyanide and hydrazone bridging ligands. This mixed metal coordination polymer exhibits interesting emission spectra by having several emissions via excitation at 230, 270, 375 and 385 nm. The catalytic activity of compound 1 in chemical CO₂ fixation was investigated in the presence of epoxides, and the effects of various parameters on its catalytic performance were evaluated. The results of catalytic studies show that compound 1 can efficiently catalyze the chemical CO₂ fixation reaction under mild conditions. The amount of co-catalyst, temperature of the reaction, nature of the solvent and also the substituent connected to the epoxide ring are some of the important parameters that have considerable effects on the catalytic activity of 1.