Effect of charge transfer with spectral analysis on the antibacterial compound 4-(Dimethyl amino) pyridine: 3,5-Dinitrobenzoic acid: Experimental and theoretical perspective

Abstract Single crystals of 4-(Dimethyl Amino) Pyridine:3,5-Dinitrobenzoic Acid ( DAPDB) were grown from solvent evaporation-solution growth technique. Optimized geometrical parameters have been compared with experimental values obtained from single XRD data. Extraordinary basicity and strong stability of this novel antifungal compound as a consequence of resonance stabilization leading to Y-aromaticity has been discussed. Hydrogen bonding and protonation character are well reflected in optimized geometry as well as bond order (BO) calculations. DFT computations at B3LYP/6-311G(d,p) level has been performed to substantiate the spectral analysis performed using FT IR, FT Raman, UV and NMR spectra. 13 C, 1 H and DEPT NMR chemical shifts of the molecule in the ground state were calculated by GIAO method and compared with the experimental values. Normal Coordinate Analysis (NCA) was performed and the electronic properties, FMOs, ESP, thermal analysis, DOS plot, etc. have been calculated and interpreted. An extensive Hirshfeld surface analysis brings out variety of intermolecular contacts and N H⋯O hydrogen bond leads to the formation of intermolecular charge transfer occurring in DAPDA.