Transition metal complexes of 2-(substituted-1H-pyrazole-4-yl)-1Hbenzo[d]imidazoles: Synthesis and characterization

Minaxi Maru1 and M. K. Shah*2

Abstract

Four novel monodentate 2-(3¢-(4²-sub-aryl)-1¢-phenyl-1H-pyrazole-4-yl)-1H-benzo[d]imidazole ligands (La-d) have been synthesized via the cyclocondensation of o-phenelyndiamine with 1,3-disubstituted pyrazole aldehydes by adding oxidizing agent ceria ammonium nitrate as catalyst in presence of hydrogen peroxide in alcoholic media. The non chelated Cu(II) and Ni(II) complexes of newly synthesized monodentate 2-substituted benzimidazole (La-d) ligands were prepared in 1:2-metal:ligand stoichiometry. The monodentate behavior of the ligand was confirmed on the basis of spectral studies. The Ni(II) complexes exhibits tetrahedral geometry where as Cu(II) complexes exhibits square planar geometry around the metal center.