Synthesis and structural analysis of tetranuclear Zn(II) complex with 2,3-dihydroxybenzaldehyde-aminoguanidine

Abstract

Here we report a new Schiff base of aminoguanidine and 2,3- dihydroxybenzaldehyde (H2L) and its physicochemical characterization, along with an investigation into its coordination affinities towards zinc. By reacting zinc acetate with the chloride salt of the ligand in the MeCN-H2O solution, yellow single-crystals of tetranuclear, centrosymmetric complex, with the formula [Zn2(?-L)(?-OAc)2]2?2MeCN, were obtained. The complex was characterized by IR spectroscopy, conductometry, elemental analysis, and single-crystal X-ray diffraction analysis. Notably, both nitrogen atoms of the aminoguanidine residue coordinate to the same zinc atom, while both deprotonated phenyl oxygen atoms achieve bridging coordination. Furthermore, two acetate anions bridge adjacent zinc atoms in addition to the Schiff base anion. Meaningful insights into the hierarchy and significance of intermolecular interactions within the crystal structure were gained by estimating the energies using the CrystalExplorer model. The calculations revealed that the crystal structure can be classified as a layer type, with notably stronger interactions occurring along the [0 0 1] and [0 1 1] directions.