Influence of double confinement on photophysics of 7-(diethylamino)coumarin-3-carboxylic acid in water/AOT/isooctane reverse micelles

Abstract

The effect of double confinement on the photophysics of 7-(diethylamino)coumarin-3-carboxylic acid (7-DCCA) inside the water pool of water/AOT/isooctane reverse micelles has been reported in this study. At first a supramolecular host-guest complex was formed in water between 2-hydroxypropyl-gcyclodextrin (HP-g-CD) and 7-DCCA. Then the aqueous solution of this complex was used to form reverse micelles at any particular w 0 value (w 0 ¼ [water]/[surfactant]). We have used sodium dioctyl sulfosuccinate (AOT) as surfactant and isooctane as non-polar solvent to prepare reverse micelles. A comparative study between double confinement system and the single confinement system, where the 7-DCCA molecule was incorporated inside the core of the water/AOT/isooctane reverse micelles, was done. We have used the steady state absorption and fluorescence emission techniques to highlight the significant shift of the spectral behaviour of the 7-DCCA due to the double encapsulation of the dye in the nanopool of the reverse micelles. More affirmation has been achieved by the use of time resolved fluorescence emission spectroscopy. The study of solvation dynamics and rotational relaxation dynamics was used as tools to investigate the effect of double encapsulation on the excited state dynamics of the probe molecule. These excited state dynamics clearly show that even at the highest w 0 value studied here, the excited state dynamics of the doubly confined dye are significantly different from those of the single confined dye in the reverse micelle. The higher values of fluorescence emission decay time, rotational relaxation and solvent relaxation times in the doubly confined system compared to those of the single confined system at different w 0 values proved the existence of the supramolecular host-guest complex inside the core of the water/AOT/isooctane reverse micelle.

Photophysics of 7-(diethylamino)coumarin-3-carboxylic acid in cationic micelles: effect of chain length and head group of the surfactants and urea

“…Very few studies are reported in the literature on the photophysics of 7-DCCA molecules. 3,[30][31][32][33][34] It is known that this molecule generally does not show any emission band related to TICT. TICT processes are non-emissive in nature for 7-DCCA.…”

“…30 We have studied the photophysical properties of 7-DCCA in cyclodextrins, reverse micelles, and in different solvents. 3,33,34 It was observed that the photophysical properties of 7-DCCA are highly dependent on the structure of the media and on the specic solute-solvent interactions. 34 In this work we have studied the photophysics of 7-DCCA in different micelles.…”

Picking Out Logic Operations in a Naphthalene β‐Diketone Derivative by Using Molecular Encapsulation, Controlled Protonation, and DNA Binding

“…The guest molecules fluorescence is generally switched on by the host–guest complex formation with cyclodextrin. Hence, studies on chemical sensing, molecular logic design, and small object recognition could take advantage of cyclodextrin as a host structure . Molecules having multiple light‐emissive electronic excited states are pertinent switching structures, and naphthalene derivatives are examples .…”

“…[20] The guest molecule's fluorescence is generally switchedo nb yt he host-guest complex formationw ith cyclodextrin.H ence, studies on chemical sensing, molecular logic design, and small object recognition could take advantage of cyclodextrin as ahost structure. [21] Molecules having multiple light-emissive electronic excited states are pertinent switching structures, [22] and naphthalene derivatives are examples. [23] Their acidities are quite varied, and in their cyclodextrin inclusion complexes,t hey can show varying acidity responses depending on the parto ft he derivative molecule en-On-off switching and molecularl ogic in fluorescent molecules are associated with what chemical inputs can do to the structure and dynamics of these molecules.…”

Photophysics and Rotational Dynamics of a Hydrophilic Molecule in a Room Temperature Ionic Liquid

“…It provides enough scope for hydrogen bonding with the surrounding medium to affect its spectral behaviour. Very few studies are reported in the literature on the photophysics of the probe 7‐DCCA . Previous study showed that charged probe molecules in RTILs, can provide strong electrostatic interaction with the medium .…”