Supramolecular Inclusion‐Assisted Disruption of Probe‐Solvent Network

Abstract

The present communication reports the disruption of probe‐solvent cluster formed by an excited state intramolecular proton transfer (ESIPT) prone molecular system and solvent water molecules because of the confinement of the probe within the cyclodextrin nano‐cavity. The disruption results in a decrease in the fluorescence anisotropy of the probe compared to its value in the aqueous medium. This is absolutely contrasting to the normal increasing trend for the fluorescence anisotropies of other fluorophores in similar constrained environments. This work substantiates the formation of probe‐solvent cluster in protic solvent and establishes the commanding role of hydrogen bonding in the solvation of the ESIPT probes.

Study on the Conformation of Entrapped Protein inside the Reverse Micellar Confinement Based on the Amino Acid Derived Ionic Liquid

“…However, once the solvation of head group is completed, the additional water molecules start to create water‐pool away from the palisade layer and does not contribute much to the rotation of ANS. Such large decrease at the initial stage was earlier noticed for 3‐Hydroxyflavone (3HF) in γ‐cyclodextrins based supramolecular assemblies . Since, it is well‐known that the solvation of the AOT head group is essentially completed within ω ∼ 10 and with further increase in water content, the microenvironment near the solvated head group region remains unaffected as the additional water coincides only to the nano water‐pool .…”

“…Such large decrease at the initial stage was earlier noticed for 3-Hydroxyflavone (3HF) in g-cyclodextrins based supramolecular assemblies. [55] Since, it is well-known that the solvation of the AOT head group is essentially completed within w~10 and with further increase in water content, the microenvironment near the solvated head group region remains unaffected as the additional water coincides only to the nano water-pool. [53] Similar phenomena might play role here for newly synthesized SAIL at very low water content (w1 ), since the water solubilization capacity of [ProC 3 ][LS]/Cy-RMs is very low compare to conventional AOT-RMs.…”

Effect of Water Microsolvation on the Excited-State Proton Transfer of 3-Hydroxyflavone Enclosed in γ-Cyclodextrin

“…S. Das and N. Chattopadhyay experimentally studied the fluorescence anisotropy of the inclusion complexes of 3HF in α-, β-, and γ-CDs compared to 3HF in the aqueous medium. The fluorescence anisotropy of these probes decreased following the order α-, β-, and γ-CD, which is attributed to the disruption of the 3HF-water network in an aqueous medium [46]. It can be stated that the micro-environment of 3HF derivatives was able to alter and prevent the self-aggregation effectively by using CDs, especially γ-CD.…”

“…One of the strategies to enhance the K* emission intensity of 3HF in an aqueous solution is disrupting the interHBs of 3HF-water cage-like network using cyclodextrin (CD) [45][46][47]. The reduction of polarity and restricted environment inside CD's cavity is essential for many aspects of photophysical phenomena by inclusion complexes between 3HF and CD [45][46][47]. CDs are the cyclic oligosaccharides consisting of the crucial α-Dglucose unit, which exhibit the conical shape and the α-D-glucose units of 6, 7, and 8 are represented as α-, β-, and γ-cyclodextrins (α-, β-, and γ-CDs), respectively [48].…”

“…From the investigation on ESPT processes of 3HF in β-, and γ-CDs [45,47], the intensity of K* of 3HF/γ-CD inclusion complex is higher than that of 3HF/β-CD inclusion complex. Consequently, the encapsulation in CDs should be a possible method to tune the fluorescence emission of 3HF derivatives and other hydrophobic compounds [45][46][47][49][50][51][52].…”