Spectroscopic Studies on Structurally Modified Anthraquinone Azo Hydrazone Tautomer: Theoretical and Experimental Approach

A series of unique four mono-azo substituted anthraquinone analogue were synthesized by using the anthraquinone components in the diazo-coupling technique. The FT-IR, 1 H NMR, and HRMS, data were used to confirm the structure of the molecules, and spectroscopic techniques like UV-Vis, and photoluminescence spectroscopy were employed to estimate the photophysical properties of the molecules. The molecular optimized geometry and frontier molecular orbitals were estimated using density functional theory. Further, global chemical reactivity descriptors parameter was theoretically estimated using the value of the highest occupied molecular orbit and lowest unoccupied molecular orbits. The anti-tubercular action of the synthesised dyes were also examined. The results of this biological activity showed that N-isopropyl aniline combined with anthraquinone N-isopropyl aniline had superior anti-tubercular activity when compared to Rifampicin as the standard. As per molecular docking studies, the synthesized compound Q1 showed excellent binding energy (-10.0 kcal/mol) among all compounds against the 3ZXR Protein. These results agreed with our in-vitro anti-TB activity results.