Synthesis and spectral characterization of new azo dye derived from benzimidazole and its complexation with selected transition metal ions

The preparation and spectral characterisation of 2-[6-(benzimidazolylazo)] as an organic heterocyclic azo dye compound containing benzimidazole. The reaction of benzimidazole diazoniumbromid with 2,4-dibromo phenol in alkaline alcoholic solution yielded -2,4-dibromo phenol (BIADBrP). Spectral analyses have been used to study the structure of the azo dye ligand such as H¹NMR, mass spectrum,IR, UV-Vis and element analysis. New six complexes with CO(III), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II) ions were prepared and identification by several physiochemical techniques; such as C.H.N element, magnatic susceptibility, atom absorption, molar conductivity, IR and electronic spectra. The used techniques showed the formation of all complexes 1:2 [M:L] complexes and suggested octahedral geometry with d²sp³ hybridization of Co(III) and sp³d² with residulechelat complexes. The coordination number of the metal ion is found to be six with binding through the phenolate O, azo N3 and with the imidazole N3 atom. The stability, geometrical, and electrical features of metal complexes have also been studied theoretically. The energy levels of the ligand and metal complexes' high occupied molecular orbital HOMO and low unoccupied molecular orbital LUMO were used to compute electrochemical potential, electrophilicity index, and chemical hardness. (paper)