zinc(ii) and mercury(ii) iodide complexes containing 2-pyridinealdoxime compound: synthesis, characterization, crystal structure determination and dft study

Two novel mononuclear complexes of [zn(paoh)2(pao)]2[zni4] (1) (paoh is 2-pyridinealdoxime or pyridine-2-aldoxime and pao is 2-pyridinealdoximato) and [hg(paoh)i2] (2) were prepared from the reactions of zni2 and hgi2 salts with 2-pyridinealdoxime ligand, respectively, in methanol. the empirical formulae of these complexes were established by elemental analyses (chno). subsequently, these complexes were characterized by 1h nmr, 13c{1h}nmr, ir and uv–vis spectroscopic techniques. moreover, the crystal structures of these complexes were characterized using single-crystal x-ray diffraction. the x-ray crystallographic analyses reveals that the structure of 1 consists of two [zn(paoh)2(pao)]+ cationic parts and one [zni4]2− anionic part. in the cationic parts, the zn(ii) cation has a distorted octahedral coordination environment by six nitrogen atoms from two 2-pyridinealdoxime and one 2-pyridinealdoximato ligands, and in the anionic part, the zn(ii) cation has a distorted tetrahedral coordination environment with four iodide anions. also, in complex 2, the hg(ii) cation has a distorted tetrahedral coordination environment by two nitrogen atoms from two 2-pyridinealdoxime ligands and two iodide anions. furthermore, the crystal packing diagram of both complexes is stabilized by intermolecular π···π interactions (in 1 and 2) and intermolecular o–h···o (in 1 and 2), c–h···o (in 1) and o–h···i (in 2) hydrogen bonds. the density functional theory calculations are carried out for the evaluation of the studied structures. the td-dft calculations, nbo analysis, complex stability by binding energy and wiberg bond indices analysis for complexes have been performed by dft calculations.