Cucurbit[7]uril Induced Formation of FRET-Enabled Unilamellar Lipid Vesicles

A unique fluorescence resonance energy transfer (FRET) process is found to be operational in a unilamellar lipid self-assembly in the aqueous phase. A newly synthesized naphthyl based long chain lipid derivative [<i>N</i>-(naphthalene-1-ylmethyl)­tetradecane-1-ammonium chloride, 14NA⁺] forms various self-assembled architectures in the aqueous phase. Controlled changes in lipid concentration lead to a transition of the self-assemblies from micelles to vesicles to rods. In the presence of cucurbit[7]­uril (CB7), 14NA⁺ forms a host–guest [2]­pseudorotaxane complex (CB7∋14NA⁺) and secondary interactions lead to the formation of a lipid bilayer with hydrophobic pockets situated in between the layers. The change in the structure of 14NA⁺ assemblies, interaction with CB7 and formation of supramolecular assemblies of CB7∋14NA⁺ were examined using light scattering, spectroscopic, and microscopic techniques. Entrapment of a luminescent dye, anthracene within the hydrophobic bilayer of the supramolecular assembly CB7∋14NA⁺ favors a modified luminescent response due to an efficient FRET process. Further, the FRET process could be controlled by thermal and chemical stimuli that induce transformation of unilamellar vesicles

A Cysteine-Specific Fluorescent Switch for Monitoring Oxidative Stress and Quantification of Aminoacylase‑1 in Blood Serum

Reagents that allows detection and monitoring of crucial biomarkers with luminescence ON response have significance in clinical diagnostics. A new coumarin derivative is reported here, which could be used for specific and efficient chemodosimetric detection of cysteine, an important biomarker. The probe is successfully used for studying the biochemical transformation of N-acetylcysteine, a commonly prescribed Cys supplement drug to Cys by aminoacylase-1 (ACY-1), an important and endogenous mammalian enzyme. The possibility of using this reagent for quantification of ACY-1 in blood serum samples is also explored. Nontoxic nature and cell membrane permeability are key features of this probe and are ideally suited for imaging intracellular Cys in normal and cancerous cell lines. Our studies have also revealed that this reagent could be utilized as a redox switch to monitor the hydrogen-peroxide-induced oxidative stress in living SW480 cell lines. Peroxide-mediated cysteine oxidation has a special significance for understanding the cellular-signaling events

Hierarchical Polyoxometallate Confined in Woven Thin Films for Single-Cluster Catalysis: Simplified Electrodes for Far-Fetched O₂ Evolution from Seawater

The highly anticipated artificial conversion of water to oxygen for the imperishable growth of renewable energy requires efficient water oxidation catalysts (WOCs) to drive the exciting 4e– transformation at low driving potentials. Herein, we describe the freestanding thin film of P5Q7 (TFPQ), where Preyssler [P5W30O110]14– (P5) clusters are woven with [CH3(CH2)6]4N(Br) chains (Q7) to confine P5 clusters and maximize its catalytic exposure. The TFPQ-supported electrode shows OER at record-low overpotentials at 10 mAcm2 (η10 = 130 and 490 mV), rapid migration of electrons (Tafel, 35 and 56 mVdec–1), turnover frequency (TOF, 8.55 s–1), in alkaline water (1 M KOH), and natural seawater, respectively. Evenly dispersed and confined conducting P5 clusters with a delocalized charge cloud shows ∼3 times lower η10 and eventually high OER efficiency than nonconfined clusters. The TFPQ electrodes showed a prolonged stability of minimum 1000 cycles in alkaline water and seawater, without the leaching of true catalytic species P5

Hierarchical Polyoxometallate Confined in Woven Thin Films for Single-Cluster Catalysis: Simplified Electrodes for Far-Fetched O₂ Evolution from Seawater

The highly anticipated artificial conversion of water to oxygen for the imperishable growth of renewable energy requires efficient water oxidation catalysts (WOCs) to drive the exciting 4e– transformation at low driving potentials. Herein, we describe the freestanding thin film of P5Q7 (TFPQ), where Preyssler [P5W30O110]14– (P5) clusters are woven with [CH3(CH2)6]4N(Br) chains (Q7) to confine P5 clusters and maximize its catalytic exposure. The TFPQ-supported electrode shows OER at record-low overpotentials at 10 mAcm2 (η10 = 130 and 490 mV), rapid migration of electrons (Tafel, 35 and 56 mVdec–1), turnover frequency (TOF, 8.55 s–1), in alkaline water (1 M KOH), and natural seawater, respectively. Evenly dispersed and confined conducting P5 clusters with a delocalized charge cloud shows ∼3 times lower η10 and eventually high OER efficiency than nonconfined clusters. The TFPQ electrodes showed a prolonged stability of minimum 1000 cycles in alkaline water and seawater, without the leaching of true catalytic species P5

Hierarchical Polyoxometallate Confined in Woven Thin Films for Single-Cluster Catalysis: Simplified Electrodes for Far-Fetched O₂ Evolution from Seawater

The highly anticipated artificial conversion of water to oxygen for the imperishable growth of renewable energy requires efficient water oxidation catalysts (WOCs) to drive the exciting 4e– transformation at low driving potentials. Herein, we describe the freestanding thin film of P5Q7 (TFPQ), where Preyssler [P5W30O110]14– (P5) clusters are woven with [CH3(CH2)6]4N(Br) chains (Q7) to confine P5 clusters and maximize its catalytic exposure. The TFPQ-supported electrode shows OER at record-low overpotentials at 10 mAcm2 (η10 = 130 and 490 mV), rapid migration of electrons (Tafel, 35 and 56 mVdec–1), turnover frequency (TOF, 8.55 s–1), in alkaline water (1 M KOH), and natural seawater, respectively. Evenly dispersed and confined conducting P5 clusters with a delocalized charge cloud shows ∼3 times lower η10 and eventually high OER efficiency than nonconfined clusters. The TFPQ electrodes showed a prolonged stability of minimum 1000 cycles in alkaline water and seawater, without the leaching of true catalytic species P5