Steady State and Time-Resolved Fluorescence Spectroscopy of Cinchonine Dication in Sodium Dodecylsulphate Micellar System.

Autor: Pant DD; Department of Physics, Birla Institute of Technology and Science (BITS) Pilani, Pilani, Rajasthan, 333031, India. ddpant@pilani.bits-pilani.ac.in.
Jazyk: angličtina
Zdroj: Journal of fluorescence [J Fluoresc] 2024 Jul 29. Date of Electronic Publication: 2024 Jul 29.
DOI: 10.1007/s10895-024-03866-8
Abstrakt: This paper reports the influence of surface charge of the micelles on to the photophysical properties of a cinchonine dication (C 2+ ) fluorophore in anionic, sodium dodecylsulphate (SDS), surfactant at premicellar, micellar and post-micellar concentrations in aqueous phase at room temperature. The magnitude of edge excitation red shift (EERS) in the fluorescence maximum of C 2+ in bulk water solution is 1897 cm - 1 whereas, in the case of SDS it is observed to be 1984 cm - 1 . The fluorescence decay curve of C 2+ fits with multi exponential functions in the micellar system. The increase in lifetime of C 2+ in SDS has been attributed to the increase in radiative rate due to the incorporation of C 2+ at the micelle -water interface. The value of dynamic quenching constant determined is 16.9 M - 1 . The location of the probe molecule in micellar systems has been justified by a variety of spectral parameters such as dielectric constant, E T (30), viscosity, EERS, average fluorescence decay time, radiative and non-radiative rate constants. All experimental results suggest that the C 2+ molecule binds strongly with the SDS micelles and resides at micellar-water interface. The binding constant (K b ) calculated (3.85 × 10 5 M - 1 ) for C 2+ in SDS revealed that the electrostatic forces mediate charge probe-micelle association.
(© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)
Databáze: MEDLINE
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