LAUSR

Abstract Hydrogen bonding interaction plays a vital role in a variety of chemical and biological process. It is primarily accountable for determining the stability of 3D-structure of folded protein counting antibodies enzymes and various biological molecules. So, here we report an intermolecular H-bonding interaction of acridine orange with 3,5-dinitro salicylic acid and quinol among four selected acceptor molecules in methanol solvent. The visible colour change was observed only when 3,5-dinitro salicylic acid and quinol mixed with acridine orange solution. UV–vis titration experiments explore the interaction through a formation of an excellent isosbestic point which indicates strong charge-transfer equilibrium. The stoichiometries of the complexes were determined as 1:1 by using Job's plot. The fluorescence quenching study was also done to find out the Stern-Volmer binding constant (KSV), quenching efficiency, binding constant (K) and binding sites (n) of the studied system. Hydrogen-bonded complexes of acridine orange were synthesized and characterized using FT-IR, 1H NMR and, elemental analysis. Detail spectroscopic study reveals the strong H-bonding interaction between acridine orange and the acceptor molecule. Further, theoretical calculation also supports the H-bonding interaction occurs through NH proton of acridine orange with acceptor molecules. TGA-DTA analyses were done to find out the thermal nature and stability of the complexes. Prepared complexes were tested for its antibacterial and antifungal activity against various bacterial and fungal strains, and they showed excellent antibacterial and antifungal activity.