Estimation of fluorescence Quantum yield of a biologically active boronic acid-Analysis of Specific interactions with alcohols and non-alcohols. (2018)

• Record Type: Journal Article
• Authors: Geethanjali, H.S.; Melavanki, R.M.; Nagaraja, D.
• Is Part Of: Materials today. Volume 5:Number 10(2018)Part 1
• Page Start: 21183
• Page End: 21188
• Publication Date: 2018
• Subjects: Quantum yield -- radiative decay constant -- non-radiative decay constant; Materials science -- Congresses -- Periodicals; 620.1
• DOI: 10.1016/j.matpr.2018.06.517
• Languages: English
• ISSNs: 2214-7853

Abstract

Abstract: The efficient emission of fluorescence intensity by solutes is characterized in terms of what is known as the Quantum yield. Quantum yield gives the probability of the excited state being deactivated by fluorescence rather than by another, non-radiative mechanism. Knowledge of quantum yield gives better insight about various aspects like; structural changes induced by solvent polarity, solute-solvent interactions, their use as standards etc. The fluorescence quantum yield ( Φ) of 2-methoxypyridin-3-yl-3-boronic acid [2MPBA] is evaluated using single point method. The value of Φ, radiative ( kr ) and non-radiative ( knr ) decay constants are calculated in non-alcohols and alcohols. The value of absorbance (OD) is decreasing with increase in solvent viscosity and it is attributed to the protonation of the excited state of fluorophores in the solvent. Also, it is observed that integrated fluorescence intensity ( Fint ) is more in solvents of high viscosity which is quite expected since solute molecules are slightly rigid in high viscous media. Φ increases from 31.7% in octanol to 78.3% in ethanol with a small exception for methanol. The higher quantum yield of 2MPBA is may be due to the presence of methoxypyridin group. The higher Φ values in alcohols are further supported by higher kr values and lesser knr values. The higher value of Φ for 2MPBA allows one to use it as a standard reference, for the estimation of relative quantum yield of other boronic acid derivatives