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Modulation of Excited‐State Proton‐Transfer Dynamics inside the Nanocavity of Microheterogeneous Systems: Microenvironment‐Sensitive Förster Energy Transfer to Riboflavin
Author(s) -
Dey Nilanjan,
Biswakarma Dipen,
Bajpai Alankriti,
Moorthy Jarugu Narasimha,
Bhattacharya Santanu
Publication year - 2019
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201801085
Subject(s) - chemistry , excited state , proton , micelle , photochemistry , pyrene , chemical physics , pulmonary surfactant , excimer , fluorescence , aqueous solution , atomic physics , organic chemistry , biochemistry , physics , quantum mechanics
The excited‐state proton‐transfer efficiency of a tetraarylpyrene derivative, 1,3,6,8‐tetrakis(4‐hydroxy‐2,6‐dimethylphenyl)pyrene (TDMPP), was investigated thoroughly in the presence of various surfactant assemblies, such as micelles and vesicles. The confined microheterogeneous environments can significantly retard the extent of the excited‐state proton‐transfer process, resulting in a distinguishable optical signal compared to that in the bulk medium. Physical characteristics of the surfactant assemblies, such as order, interfacial hydration, and surface charge, influence the proton transfer process and allow multiparametric sensing. A higher degree of interfacial hydration facilitates the proton‐transfer process, while the positively charged head groups of the surfactants specifically stabilize the anionic form of the probe (TDMPP−O*). Furthermore, Forster energy transfer from the probe to riboflavin was studied in a phospholipid membrane, wherein the relative ratio of the neutral versus anionic forms (TDMPP‐OH/TDMPP−O*) was found to influence the extent of energy transfer. Overall, we demonstrate how an ultrafast photophysical process, that is, the excited‐state proton transfer, can be influenced by the microenvironment.