A study on the interaction of nile blue with Uracils: A spectroscopic and computational approach

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 246; p. 119011
• Main Authors: Sambathkumar, S., Manivannan, C., Baskaran, S., Kumar, R. Raj, Anbazhagan, V.
• Format: Journal Article
• Language: English
• Published: England Elsevier B.V 05-02-2021
• Subjects: Antioxidant activity; Fluorescence quenching; Nile blue; Oxazines; Spectrometry, Fluorescence; Thermodynamics; Uracil; Uracil; Nile blue; Antioxidant activity; Fluorescence quenching
• ISSN: 1386-1425; 1873-3557
• DOI: 10.1016/j.saa.2020.119011

The present work focuses the investigation on fluorescence quenching of nile blue (NB) in presence of various substituted uracil molecules. UV–Visible absorption studies signify the possibility of ground state complex formation between NB and uracil molecules. The increase in concentration of quencher molecules greatly influences the emission spectra of NB. The bimolecular quenching rate constant (kq) were calculated and found to depend on the position and electronic properties of substituent in quencher molecules. Fluorescence quenching experiments were performed at different temperature to calculate the thermodynamic parameters. The fluorescence lifetime measurements show that the quenching process proceeds through static quenching. The mechanism of fluorescence quenching includes the possibility of proton transfer. The bond dissociation enthalpy (BDE) reveals the release of H from the quencher molecules. The quencher molecules possess antioxidant activity and identified using deoxyribose degradation assay. The position of substituent and its electronic property are key features to address the antioxidant activity of uracil molecules.
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•Photoinduced interaction was probed by steady state and time resolved measurements.•The fluorescence quenching depend on position and substituent of uracil molecules.•Lifetime measurements reveal static quenching mechanism.•BDE, calculated by B3LYP program impacts the antioxidant activity of uracils.•The antioxidant activity was studied in-vitro by deoxy ribose degradation assay.