Local Atomic Structure of Co(II), Ni(II), and Cu(II) Metal Chelates Based on 1-Phenyl-3-methyl-4-formyl-5-pyrazolone and 1-Aminobenzimidazole Derivatives

A series of new Co(II), Ni(II), and Cu(II) metal chelates based on 1-phenyl-3-methyl-4-formyl-5-pyrazolone and 1-aminobenzimidazole derivatives was obtained. The composition and spectral properties were studied by elemental analysis, ¹H NMR spectroscopy (for HL), and IR spectroscopy. The parameters of the local atomic environment of the metal ions in these complexes were determined by X-ray absorption spectroscopy. The experimental structural data were confirmed by calculations of the optimized complex structures using density functional theory. The important role of additional donor centers (S, Se) and substituents at the imine nitrogen atom in the aminobenzimidazole fragment of the ligands in the geometry of the coordination site of the complexes was demonstrated.