Synthesis of mixed ligand Mn(II) complex, investigation of its structural, spectroscopic and DNA binding properties

In this study, the mixed ligand Mn (II) complex containing 4-methoxypyridine-2-carboxylic acid and 4,4'-dimethyl-2,2'-bipyridine was synthesized and the structure was solved by using single crystal X-ray diffraction method. According to the results of X-ray diffraction, the mixed ligand Mn (II) complex has an octahedral coordination geometry symmetry. FT-IR and UV-Vis spectra were recorded to examine the vibrational and electronic properties of Mn(II) complex. According to the FT-IR results, the 4-methoxypyridine-2-carboxylic ligand was coordinated to central Mn (II) ion through the carboxyl group O atom and the pyridine ring N atom as the two dentate ligand. According to the results obtained from the UV-Vis spectrum, high energy ligand-ligand and metal-ligand charge transfer transitions were observed in the complex. Then, the density, functional theory (DFT) calculations were performed to obtain more detailed information about the structural, spectroscopic, electronic and non-linear optical properties of the synthesized Mn (II) complex. IR vibration wavenumbers obtained with B3LYP level and LanL2DZ basis set was scaled with 0.96. The results of the calculations for the complex were found to be consistent with the experimental data. According to natural bond orbital analysis, there are high energy conjugative interactions in the complex. In addition, the synthesized Mn (II) complex has been found to be a very good candidate for nonlinear optical materials according to the large first-order hyperpolarizability parameter (β = 332,9736 × 10-30 esu). Molecular docking studies have been conducted to investigate the atomic level interactions of Mn (II) complex with DNA. Numerous π-anion, C•••O, and π-alkyl interactions were found between the Mn (II) complex and the target DNA.