Synthesis of two new Schiff bases; crystal structure, Hirshfeld surface analysis, density functional theory and molecular docking

Abstract

Schiff bases are versatile and readily available compounds that exhibit a wide variety of applications in various fields of chemistry. Two new targeted Schiff bases (E)-4-(1-(2-hydroxy-5-methyl-3-nitrophenyl)ethylideneamino)-2,3-dimethyl-1-phenyl-1,2-dihydropyrazol-5-one (1) and (E)-1-(4-(2‑hydroxy‑3-methylbenzylideneamino)phenyl) ethanone (2) were synthesized by using already reported protocol with good yield. Single X-ray diffraction technique was used for complete structure elucidation which confirmed that compound 1 is triclinic while 2 is orthorhombic. For the optimization of synthesized Schiff bases, a hybrid functional method B3LYP and 6–31G(d,p) basis set were used. DFT calculations can be used to estimate the energy gaps between different orbitals and to correlate the bond angle and bond length of the targeted compounds with experimental data retrieved from XRD results. Hirshfeld surface analysis (HS) and two dimentional fingerprint plots were used to elaborate the intermolecular interactions along contact contribution in the crystalline molecules. Molecular Operating Environment (MOE) program was used to perform the docking studies of the crystalline compounds against AChE and BChE. From the results of binding affinity and docking score, it was depicted that compound 1 is relatively more active than that of compound 2 across both tested enzymes.