Effect of fluorescence quenching on 6BAAC in different solvents

Abstract

The fluorescence quenching studies of 6-bromo-3-azidoacetyl coumarin (6BAAC) by aniline in four different solvents, namely acetonitrile, benzene, dioxane, and toluene, were carried out at room temperature to understand quenching mechanisms. The Stern-Volmer plots have been found to be nonlinear with a positive deviation for all the solvents studied. To interpret these results we have invoked the ground state complex formation and sphere of action static quenching models. Using these models various quenching rate parameters have been determined. The magnitudes of these parameters suggest that the sphere of action static quenching model agrees well with the experimental results. Hence the positive deviation is attributed to the static and dynamic quenching. Further, with the use of the finite sink approximation model, it was possible to check these bimolecular reactions as diffusion-limited and to estimate independently distance parameter R= and mutual diffusion coefficient D. Finally an effort has been made to correlate the values of R= and D with the values of the encounter distance R and the mutual coefficient D determined using Edward's empirical relation and the Stokes-Einstein relation. PACS Nos.: 33.50.-j, 87.64.Ni, 31.70.Hq, 87.15.Kg.Résumé : Nous avons étudié à la température de la pièce, l'extinction de fluorescence de la coumarine 6-bromo-3-azydoacétyle (6BAAC) par de l'aniline dans les quatre solvants suivants, l'acétonitrile, le benzène, le dioxane et le toluène, ceci afin de mieux comprendre le mécanisme d'extinction. Nous trouvons que les graphiques de Stern-Volmer sont non linéaires, avec une déviation positive pour tous les solvants étudiés. Afin d'interpréter ces résultats, nous faisons appel à deux modèles d'extinction statique, la formation de complexe dans l'état fondamental et la sphère d'action. Ces modèles ont permis de déterminer différents paramètres de taux d'extinction. Les résultats indiquent que le modèle de la sphère d'action est en bon accord avec les résultats expérimentaux. Conséquemment, la déviation positive est attribuée à l'extinction statique et dynamique. De plus, le modèle de l'approximation Finite Sink permet à la fois de vérifier que ces réactions bimoléculaires sont limitées par diffusion et d'estimer de façon indépendante le paramètre de distance R= et le coefficient de diffusion collective D. Finalement, en utilisant la relation empirique de Edwards et la relation de Stokes-Einstein, nous nous efforçons de corréler les valeurs de R= et de D avec les valeurs de la distance de rencontre R et de diffusion collective D. [Traduit par la Rédaction]

Bimolecular fluorescence quenching reactions of the biologically active coumarin composite 2‐acetyl‐3H‐benzo[f]chromen‐3‐one in different solvents

“…In our case, the S–V plot displayed upward curvature for the 2AHBC molecule in all the solvents and is shown in Figure . The upward curve in the S–V plot indicated the existence of static quenching either due to ground state complex formation or the sphere of action static quenching model . Similar results were consistent with previous reports in the literature …”

“…In this model, the non‐linearity in the S–V plot can be explained either due to ground state complex formation or the sphere of action static quenching model …”

Investigation of the Fluorescence Turn-off Mechanism, Genome, Molecular Docking In Silico and In Vitro Studies of 2-Acetyl-3H-benzo[f]chromen-3-one

“…The obtained results were correlated with the literature. − It is observed that the calculated values of encounter distance ( R ) are almost double the kinetic distance ( r ) in all of the binary solvent mixtures. This demonstrates that the present work obeys the sphere of action model and hence confirms the presence of static quenching reactions. However, static effects can also be evident from diffusion-limited reactions .…”

Effect of fluorescence quenching model on quinoline derivative with cobalt chloride metal ion using steady state and time resolved spectroscopic methods

“…[30] Dynamic quenching involves diffusion of quencher into fluorophore while the duration of excited state lifetime and hereafter, fluorophore goes back to ground state with no emission of photon. [31][32][33][34][35][36] This in turn affects lifetime of fluorophore in the excited state. When a non-linear variation is observed in Stern-Volmer plot, it could be an indication of the quenching mechanism not being solely dynamic.…”