SYNTHESIS AND INFRARED-SPECTROSCOPIC STUDY OF COMPLEXES OF SELECTED 3D-METALS WITH 2-(2-PYRIDYL)-BENZIMIDAZOLE

The aim of this study was to synthesize and systematically investigate the coordination compounds of several 3d metals with 2-(2-pyridyl)benzimidazole (2-PBI) using infrared (IR) spectroscopy. Complexes of copper(II), nickel(II), and cobalt(II) with the general formula [M(2-PBI)3](ClO₄)₂were successfully synthesized. Based on the analysis of the IR spectra, it was established that the 2-PBI ligand coordinates to the metal ion in a bidentate manner through the nitrogen atoms of the benzimidazole and pyridyl rings. The shifts of the ν(C=N) and ν(C–N) stretching vibration bands, as well as the appearance of new bands in the 623–485 cm⁻№ region corresponding to ν(M–N) and vibrations, confirm the formation of coordination complexes. It was determined that the [M(2-PBI)3](ClO₄)₂complexes possess an octahedral geometry.