Solvent effect on the fluorescence quenching of biologically active carboxamide by aniline and carbon tetrachloride in different solvents using S–V plots

Kusanur³

et al. 2018

Luminescence

A study on fluorescence quenching was carried out for the coumarin derivative 2-acetyl-3H-benzo[f]chromen-3-one (2AHBC) with aniline at room temperature. Efficient fluorescence quenching was observed and Stern-Volmer (S-V) plots showed upward curves from linearity in all solvents of different polarities. For the solute 2AHBC, ground state complex formation does not hold in our study. The kinetic distance (r) value was found to be greater than the encounter distance (R) and indicated that the quenching reaction was held within the sphere of action. Diffusion-limited reactions were found to be more prominent in high polarity solvents, namely dimethyl sulfoxide (DMSO), DMF, ACN, methanol, ethanol, propanol and DCM. The relationships between quenching constant (K ) and dielectric constants (ε) of the different solvents were studied.

Section: Resultssupporting

confidence: 93%

Section: Theorymentioning

confidence: 99%

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

Koppal

Kusanur³

et al. 2018

Luminescence

“…Using these values of K SV 0 and D, the distance parameter, R=, was determined according to (5) and the values of R= are given in Table 3. From the values of distance parameter R= and encounter distance R activation energy controlled rate constant k a was also determined according to (6). This value of k a can Table 2.…”

Section: Resultsmentioning

confidence: 99%

“…The combination of organic and inorganic components can lead to a material with unusual properties that might not be achieved with each component separately. The fluorescence quenching of aromatic hydrocarbons in solventsbyvariousquencherslikecarbontetrachloride,bromobenzene, aniline, halide ions, ethyltrihiocarbonate, metal ions, etc., has been a subject of continued investigation for the last couple of decades [1][2][3][4][5][6][7][8][9][10][11]. Our study is mainly to understand the nature of bimolecular reactions.…”

Section: Introductionmentioning

confidence: 99%

Effect of fluorescence quenching on 6BAAC in different solvents

Patil

2014

Can. J. Phys.

Self Cite

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]

“…It is vital for design and development of specific chemo sensors to comprehend and control quenching processes. Many investigators have found their interest towards florescence quenching due to such tremendous novel applications . Such potential and fascinating properties of coumarins and diversified uses of fluorescence quenching including significance in the field of bio analysis inspired us to conduct the present investigation.…”

Section: Introductionmentioning

confidence: 99%

Effect of viscosity and dielectric constant variation on fractional fluorescence quenching analysis of coumarin dye in binary solvent mixtures

Bhavya¹,

Kusanur³

et al. 2018

Luminescence

Photo physical properties of fluorescent organic compounds give an immense improved knowledge on characteristics of excited state that is beneficial to devise innovate molecules and understand their performance in particular applications. Coumarin derivatives have been extensively investigated in this regard. This article narrates steady state fluorescence quenching measurements of a coumarin derivative namely 3-hydroxy-3-[2-oxo-2-(3-oxo-3H-benzo[f]chromen-2-yl)-ethyl]-1,3-dihydro-indol-2-one (3HBCD) in a binary mixture of acetonitrile and 1,4-dioxane. Aniline is used as quencher. Fluorescence intensity is large in acetonitrile and decreases as the percentage of 1,4-dioxane in the solvent mixture increases. With modest quencher concentration a deviation towards the x axis is noticed in the Stern-Volmer (S-V) plots. This downward curvature is interpreted as due to the presence of 3HBCD in different conformers in the lowest energy level. Ground state intramolecular hydrogen bonding formation is observed due to the conformational changes in the solute. Figured estimations of various quenching parameters recommend that, while dynamic quenching prompts linearity in S-V plot at lower quencher concentration, increasing quenching efficiency with increasing medium viscosity suggests that reaction is not entirely controlled by material diffusion. Stern-Volmer constant increases with decreasing medium dielectric constant.