Abstract
A variety of synthetic routes to benzimidazole derivatives have been reported based on different heterocyclic rings such as Schiff bases, 2-azetidinone, 4-thiazolidinone and 1,3-oxazepan. Additionally, HOMO-LUMO and vibrational wavenumbers which represent 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.