Structural investigation, spectroscopic and energy level studies of Schiff base: 2-[(3′- N -salicylidenephenyl)benzimidazole] using experimental and DFT methods

Abstract

The Schiff base 2-[(3′-N-salicylidenephenyl)benzimidazole] (Spbzl) was characterized by FT-Raman, 1 H NMR, 13 C NMR and single crystal X-ray diffraction technique. Crystallographic studies reveal the presence of two water molecules in the asymmetry unit which aid the intermolecular hydrogen bonding with imidazole ring, and the trans-conformation of the azomethine bond. Theoretical computations conducted using density functional theory (DFT) analysis support the experimental facts. Energy levels estimated by DFT studies are in good agreement with the values obtained from cyclic voltammetry technique. Frontier molecular orbital analysis shows that charge transfer has taken place from donor to acceptor moiety, which is also supported by the high hyperpolarizability values in both gaseous and solution phases, indicating high charge transfer capability of the molecule. A comparative theoretical study of Spbzl with derivative 4-((3-(1H-benzimidazol-2-yl)phenylimino)methyl)-3-hydroxybenzoic acid (Pbzlb) having an added anchor group COOH substituted at para position in the acceptor ring has been made. The result shows the feasibility of charge transfer to the semiconductor surface in dye sensitized solar cell (DSSC) applications for Pbzlb.

In Vitro Evaluation of the Potential Pharmacological Activity and Molecular Targets of New Benzimidazole-Based Schiff Base Metal Complexes

“…1 H NMR spectra show the characteristic signals of the different systems present in these Schiff bases [ 34 , 35 , 36 ]. At a low field, the signals corresponding to the protons of the imidazole and the -OH present in the salicylidene ring were observed.…”

Synthesis, biological evaluation and model membrane studies on metal complexes containing aromatic N,O-chelate ligands

“…The infrared spectra were obtained using a Shimadzu Affinity 1 (FT-IR) spectrometer. 1 H and 13 C{ 1 H} NMR spectra of the benzimidazolyl-phenol ligands and its lanthanide complexes were recorded on the Bruker Avance II 400 spectrometer using DMSO-d 6 as a solvent. The thermal analysis was performed on the TGA 550 TA Instruments analyzer under nitrogen atmosphere between 50 and 500 C, with a heating rate of 10 C⋅min À1 .…”

“…Benzimidazoles are a class of bioactive heterocyclic compounds that display a wide range of useful biological and clinical applications [1]. The benzimidazole backbone represents a privileged structure in medicinal chemistry due to its broad spectrum of pharmacological and therapeutic applications, which include, antimicrobial, antiviral, antiparasitic, anti-inflammatory, antidiabetic and anticancer activities, among others.…”

Synthesis, Characterization and Antimicrobial Activities of Copper(II) Complexes of Schiff Base Ligand 2-[(3′-N-salicylidinephenyl)benzimidazole]

“…The solid was filtered, dried and recrystallized in methanol. The X-ray crystallographic studies of the ligand is reported elsewhere [30]. m.p.…”