Effect of Hydrogen Bonding on Fluorescence Quenching of Quinolin-8-Ol - Analysis Using Negative Stern-Volmer Plots

Abstract

Photophysics of fluorescent organic compounds give a better knowledge of the excited state properties which in turn will help in the design of newer molecules and understanding their performance in specific applications. Here we present the fluorescence quenching study of a Quinolin-8-ol (QO) in toluene and butanol solvents by steady state fluorescence measurements. Anilineis the quencher. Negative deviation in the Stern -Volmer (S-V) plots has been observed with moderate quencher concentration. The downward curvature in the S-V plot is interpreted in terms of existence of different conformers of the solute in the ground state. The formation of intermolecular and intra molecular hydrogen bonding is found to be responsible for the conformational changes in the ground state of the solute. Quenching data is analyzed by modified Stern-Volmer equation or Lehrer equation. KEYWORDS:Quinolin-8-ol (QO), fluorescence quenching, modified Stern-Volmer (Lehrer) equations and hydrogen bonding.

Green synthesis, characterization, and antimicrobial applications of silver nanoparticles as fluorescent nanoprobes for the spectrofluorimetric determination of ornidazole and miconazole

“…The static quenching occurs due to the ground state complex formation. While, in dynamic quenching, the quencher (ONZ or MIZ) diffuses in the excited state to the fluorophore and contacts with it 56 . Another difference between the two prescribed mechanisms is the dependency on temperature.…”

“…The possible quenching mechanisms were investigated using Stern–Volmer Eq. ( 5 ): where (F 0 ) and (F) are the fluorescence intensities before and after adding the drug, K SV is the Stern–Volmer (S–V) constant, [Q] is the concentration of quencher 56 .…”