Synthesis, Molecular Structure, Hirshfeld Surface Analysis, Spectroscopic and Computational Studies (DFT) of 6,6'-((1E,1'E)- (1,2-phenylenebis(azanylylidene))bis(methanylylidene))bis(2- (tert-butyl)-4-methylphenol)

Schiff bases have been used in biological processes and as chelating agents for several decades. This work presents the synthesis and characterization of compound, N,N’-Bis(3-tert-Butyl-5-methylsalicylidene)-1,2-diamino phenylene as the Schiff base derivative with the reaction of an aromatic aldehyde derivative and o-phenylenediamine. The spectroscopic properties of the compound were examined by FT-IR, 1 H NMR, 13 C NMR,  MS and elemental analyses. The molecular structure of the compound was also confirmed using X-ray single-crystal data. And also theoretical calculations were obtained by using Density Functional Theory (DFT) methods. T he structural parameters were calculated by using DFT/B3LYP/6-31G(d,p) basis set in ground state. Molecular Electrostatic Potential (MEP) map and the frontier molecular orbitals (HOMO-LUMO) of the compound were created by using the optimized structures. The results of theoretical study using the DFT method at the B3LYP/6–31G(d,p) level are in good agreement with the experimental data . Hirshfeld surface analyses and two dimensional fingerprint plots were used to analyse the intermolecular interactions present in the crystal, indicating that the most important contributions for the crystal packing are from H ∙∙∙ H (71.2%), H ∙∙∙ C/C ∙∙∙ H (18.7%), C ∙∙∙ C (4.8%) and H ∙∙∙ N/N ∙∙∙ H (2.7%) interactions.