Crystal structure, DFT study, antimicrobial properties and DNA cleavage potential and thermal behavior of some new mercury complexes

In this study, a new bidentate Schiff base ligand (L) entitled as N,N’-bis(dimethylaminocinnamaldehyde)-2,2-dimethyl-1,3-propanediamine and its mercury complexes were synthesized. The Schiff base ligand and its complexes were characterized using FT-IR, 1H-, 13C-NMR spectroscopy, molar conductivity and electronic spectral study. Regarding physical and spectral data, the general formula for the complexes was suggested as HgLX2 (L = Schiff base ligand and X = Cl−, Br−, I−, SCN−, N3 −). For structural identification of these complexes, crystal structure of mercury iodide complex was analyzed as typical one. In the structure of this complex, Hg ion is surrounded by 2 iodide ions and 2 N atoms from the Schiff base ligand to form a four-coordinated mercury complex in triclinic system with space group of P 1. Angular index (τ 4) value was evaluated equal to 0.85, so the geometry around the mercury ion in this complex can be described as trigonal pyramid. A layered supramolecular structure for HgLI2 complex is stabilized by C–H···I and C–H···π interactions in solid state. DFT study on the ligand and its complexes was also carried out, and then some calculated and experimental structural parameters of HgLI2 were compared. Thermal behaviors of the titled compounds were investigated by thermogravimetric analyses. Furthermore, biological properties of the ligand and its complexes were examined against some Gram-negative and Gram-positive bacteria and also against 2 fungi. Finally, the interaction of the ligand and its complexes with DNA was investigated by electrophoresis method.