Synthesis Structural Study and Spectroscopic Characterization of Azo Compound Derived from Mercaptothiadiazole and Methoxybenzaldehyde

Abstract

The vibrational and electronic properties of 2-hydroxy-5-((5-mercapto-1,3,4-thiadiazol-2-yl)diazenyl)-3-methoxy benzaldehyde were theoretically studied in the present paper by carrying out quantum chemical calculations. Vibrational wavenumbers and their respective assignments were computed at the Hartree-Fock and DFT/B3LYP levels with the 6-311++G(d,p) basis set using Gaussian03 software. The theoretical IR and Raman spectra were calculated and compared with the experimental IR spectrum, which showed good agreement. The vibrational assignments were made by PEG analysis to ensure proper characterization of the modes. Theoretical IR and Raman intensities have also been calculated to provide further spectroscopic insight. Frontier molecular orbitals have been estimated to obtain an in-depth analysis of the electronic structure. (FMOs) were analyzed. The HOMO and LUMO energies have been computed thereby giving HOMO–LUMO energy which, in turn, gives insight into the reactivity and stability of the molecule. Also, Mulliken charges and Molecular Electrostatic Potential (MEP) analysis were computed for charge transfer character and electrostatic interaction within the molecule, respectively. This study is also supplemented by Natural Bond Orbital (NBO) analysis of charges to investigate intramolecular and intermolecular charge delocalization effects on their mean stabilization interactions in the system. Thus, it can parse from the electronic and vibrational features that it can be useful in spectroscopic applications further in molecular design. The paper would, therefore, reveal the power that computational chemistry brings in the prediction and interpretation of vibrational and electronic properties that would go a long way to unravel compounds structurally similar to the heterocyclic compound.