A VARIETY of synthetic routes to benzimidazole derivatives have been reported based on different hetero-cyclic rings such as Schiff bases, 2-azetidinone, 4-thiazolidinone and 1,3-oxazepan. Additionally, HOMO-LUMO and vibrational wavenumbers which represents the quantum mechanical calculations of energies, were conducted by Density functional theory (DFT) method at the level of B3LYP with 6-31G(d,p) basis set. FTIR, ¹H NMR spectroscopy and spectral mass spectrometry were used to characterize these compounds; this was followed by measuring the biological activities for gram-negative, gram-positive bacteria and fungi by using diffusion protocol. The outcomes of DFT calculations showed consistency between the experimental values and theoretical of the vibrational and NMR spectroscopy.

New succession related to the transition metal complexes Cu(II), Ni(II), and Co(II) with 4-((Z)-4-bromobenzylidene)-2-(7-((4bromobenzylidene)amino)-3methyl-8oxo-5-thia-1azabicyclo[4.2.0]oct-2-en-2yl)oxazol-5(4H)-one) has been prepared and described. The structural descriptions have been reached from FT-IR, UV Vis-Spectrophotometer, molar conductance measurements, magnetic susceptibility, atomic absorption techniques as well as 1 HNMR. Based on these results, it is proposed that the coordinates of the ligand to metal ions from the nitrogen related to azomethine group as well as the oxygen of carbonyl group. In addition, the biological activity of the complexes and the ligand has been investigated opposite Staphylococcus aureus, Aspergillus Niger, E.coli, and Candida albicans. The products indicate that Co (II)-complex, Ni (II)-complex and Cu (II) -complex is the enhanced biological activity in comparison to the ligand.