Structural, spectroscopic, radical scavenging activity, molecular docking and DFT studies of a synthesized Schiff base compound

Abstract

A synthesized Schiff base, (E)-4-nitro-2-[(o-tolylimino)methyl]phenol (L), was prepared and characterized by FT-IR, single crystal X-Ray diffraction, NMR chemical shift and UV–Vis. spectroscopic techniques. Theoretical calculations of L were performed by using density functional theory (DFT) calculations with the B3LYP/6-311++G (d,p) level in the ground state. The obtained calculation geometry was found to be in well consistent with the experimental geometry. X-ray diffraction investigation shows that the L crystallized in phenol-imine form with OH⋯N intramolecular hydrogen bond. X-ray diffraction and Hirshfeld surface analysis were done to examine the contribution of intermolecular contacts in crystal packing of L. Frontier molecular orbitals, electronic absorption wavelengths and non-linear optical features of the L were investigated with molecular modeling methods. It worthy of note that, the radical scavenging activities of L were examined by using ABTS•+, DMPD•+ and DPPH• assays. According to acquired results, L shows effective DPPH• (SC50 10.99 ± 0.12 μg/mL), DMPD•+ (SC50 11.51 ± 0.16 μg/mL), and ABTS•+ (SC50 8.55 ± 0.17 μg/mL) scavenging activities compared with standard antioxidant compounds such as Trolox (TRO), rutin (RUT) and butylated hydroxy anisole (BHA). Molecular docking study was carried out to predict the potency of inhibition of L against mitochondrial Ubiquinol-Cytochrome C Reductase binding (UQCRB) protein. The molecular docking results showed that the L exhibited a good activity with −7.80 kcaL/mol value of binding affinity energy.