Studies of metal complexes of 2-(2-pyridinyl)-, 2-(6-methyl-2-pyridinyl)-, 2-(3-pyridinyl)-1H-benzimidazoles with some d(8-10) ions

Abstract

2-R-1H-Benzimidazoles [L-1, R = 2-pyridinyl; L-2, R = 6-methyl-2-pyridinyl; L-3, R = 3-pyridinyl] and their complexes with Ni(II), Pd(II), Zn(II), Cd(II), Hg(II) chloride were prepared. The complexes, having 1:1 and 1:2 metal:ligand ratios, were characterized by elemental analyses, magnetic susceptibility and molar conductance measurements, IR and H-1 NMR spectroscopy. The Ni(II) complexes are paramagnetic. The metal:ligand ratio are 1:1 in the Pd(II) and Hg(II) complexes of the ligands, and these complexes are non-ionic. in the IR spectra the band character and vibrational frequencies of the groups participating in coordination changed on complexation In the H-1 NMR spectra, considerable changes were found in the chemical shifts of protons neighboring to the coordinated nitrogen atoms. The ligands L-1 and L-2 give chelates easily with the metal ions, but L-3 does not.