Directed Molecular Recognition: Design and Synthesis of Neutral Receptors for Biotin To Bind Both Its Functional Groups

The neutral receptors 1 and 2 are designed and synthesized for the recognition of biotin, a biologically significant molecule, in chloroform to bind completely both of its functional groups simultaneously, i.e., cyclic urea and the carboxyl groups. The truncated receptor 3 binds only the cyclic urea moiety

Strategy to Design a Flexible and Macromolecular Sensor to Bind Cd²⁺ Ions: A Complete Photophysical Analysis and Bio-Imaging Study

A novel triazole-bridged coumarin–benzimidazole-conjugated fluorescence sensor (4) has been developed for selective detection of Cd2+ over other competitive metal ions. The sensor exhibited quick “turn-on” responses upon interaction with a very low level of Cd2+ (14 nM). The photophysical changes in the complexation of Cd2+ with sensor 4 have been explained through the excited-state intramolecular proton transfer mechanism. The involvement of benzimidazole and triazole moieties in Cd2+ binding was confirmed by different spectroscopic techniques such as UV–vis, Fourier transform infrared, nuclear magnetic resonance, and ESI mass. The diameter of the circular shape of the sensor decreased upon complexation with Cd2+, which was confirmed by field-emission scanning electron microscopy. Furthermore, the quantum chemical (density functional theory) calculation supported the mechanism of interactions and the mode of binding of 4 toward Cd2+. The sensor was more effective for finding Cd2+ in two living cells, C6 (rat glial cell) and Hep G2 (human liver cell)

Strategy to Design a Flexible and Macromolecular Sensor to Bind Cd²⁺ Ions: A Complete Photophysical Analysis and Bio-Imaging Study

A novel triazole-bridged coumarin–benzimidazole-conjugated fluorescence sensor (4) has been developed for selective detection of Cd2+ over other competitive metal ions. The sensor exhibited quick “turn-on” responses upon interaction with a very low level of Cd2+ (14 nM). The photophysical changes in the complexation of Cd2+ with sensor 4 have been explained through the excited-state intramolecular proton transfer mechanism. The involvement of benzimidazole and triazole moieties in Cd2+ binding was confirmed by different spectroscopic techniques such as UV–vis, Fourier transform infrared, nuclear magnetic resonance, and ESI mass. The diameter of the circular shape of the sensor decreased upon complexation with Cd2+, which was confirmed by field-emission scanning electron microscopy. Furthermore, the quantum chemical (density functional theory) calculation supported the mechanism of interactions and the mode of binding of 4 toward Cd2+. The sensor was more effective for finding Cd2+ in two living cells, C6 (rat glial cell) and Hep G2 (human liver cell)

Directed molecular recognition: furfurylamine appended ditopic receptor for succinic acid

<div><p>A furfurylamine appended ditopic receptor (<b>R1</b>) for dicarboxylic acids has been designed and synthesised. The association constants (<i>K</i>_a) between receptors and dicarboxylic acids have been determined using UV–vis and NMR titration techniques. The binding constant (<i>K</i>_a) of succinic acid with <b>R1</b> was observed maximum, which implies the optimum chain length selectivity for succinic acid. Theoretical calculation and molecular modelling using Gaussian 03 program also support the optimised receptor's cavity for succinic acid.</p></div

Photo-physical aspects of BODIPY-coumarin conjugated sensor and detection of Al³⁺ in MCF-7 cell

BODIPY azine bearing chemosensor R1 has been synthesised for selective detection of Al3+with visual colour change from red-purple to purple and photo-physical studies were explained through Förster Resonance Energy Transfer (FRET) mechanism. Chemosensor showed good sensing capability with high binding constant and lower Limit of Detection (LOD) towards Al3+. Cell viability and fluorescence microscopic experiments illustrated about the cytocompatibily of the sensor in presence of Al3+ in living cells (MCF-7).</p

Detection of Hg²⁺ ion using highly selective fluorescent chemosensor in real water sample and <i>in-vitro</i> cell study upon breast adenocarcinoma (MCF-7)

A novel rhodamine-based chemosensor (R) was designed and synthesised for selective recognition of Hg2+ ion in real water samples collected from different places. The chemosensor was prepared in green condition with high yield. The selectivity of R was examined with various metal ions, among which only Hg2+ was identified selectively with off–on mechanism along with enhancement of fluorescence. Metal ions recognition has been carried out using UV–vis and fluorescence studies taking µM concentration of chemosensor R in HEPES buffer. The detection limit of R was calculated and found to be 4.4 × 10–9 M. Quantum chemical (DFT) calculation was carried out in order to acquire knowledge about the stability of R in presence of Hg2+ ions. Cell viability and fluorescence microscopic experiments showed R as cytocompatible and can be used as a fluorescent probe for detecting Hg2+ in living cells. Detection of Hg2+ ion using highly selective fluorescent chemosensor in real water sample and in-vitro cell study upon breast adenocarcinoma (MCF-7) Ashish Kumara, Sumit Kumar Hirab, Partha Pratim Mannac and Swapan Deya*</p

Indole<b>-</b>based distinctive chemosensors for ‘naked-eye’ detection of CN and HSO₄⁻, associated with hydrogen-bonded complex and their DFT study

<p>Colorimetric detection of anions (<b>HSO</b>_<b>4</b>^<b>−</b> and <b>CN</b>^<b>−</b>) was achieved via analyte triggered colour changing of the dipodal and tripodal sensors in CH₃CN–H₂O (1:1). The sensors exhibited very sharp visual colour changes and fluorescence quenching–enhancing effect upon addition of the <b>HSO</b>_<b>4</b>^<b>−</b> and <b>CN</b>^<b>−</b>. The large downfield shift of the NH proton signals in ¹H-NMR complexation studies and quantum chemical DFT calculations proved the formation of hydrogen-bonded complexes where no proton transfer mechanism was found.</p> <p>Indole based dipodal and tripodal fluorescence ‘<i>on-off</i>’ chemosensors exhibit a selective colorimetric sensing ability towards HSO₄⁻ and CN⁻ ions. ¹H-NMR study and quantum chemical DFT calculations with MEP diagram proves the formation of hydrogen bonded complexes.</p

Novel Class of Isoxazole-Based Gelators for the Separation of Bisphenol A from Water and Cleanup of Oil Spills

A series of low-molecular-weight gelators based on an isoxazole backbone were synthesized, which showed robust and phase-selective gelation of a series of oils. Due to their excellent phase-selective and cogelation properties, they were employed for the separation of bisphenol and the recovery of oil spills from water. The driving force and morphology of these gels were characterized by spectroscopic and microscopic studies

Polynaphthalene-Based Oxazaborinine Complexes Formulated as Red Light Emitters and High-Performance Asymmetric Supercapacitors

Developing a solid organic emitter based on an oxazaborinine complex with improved photophysical characteristics has become essential to fulfilling the rising need for optical and electrochemical technology. Two oxazaborinine complexes (TNB (a tri-naphthalene boron complex) and DNB (a di-naphthalene boron complex)) decorated with naphthalene and triphenylamine have been developed, which show emission in the red light region in the solid phase. Their effectiveness as asymmetric supercapacitor electrodes in aqueous electrolytes is also being studied. Polynapthaldimine-substituted DNI (di-naphthalene imine) and TNI (tri-naphthalene imine) have been initially synthesized and converted to a N,O-linked boron complex. TNB in solids (λem 660 nm) and the polydimethylsiloxane (PDMS) composite (λem 632 nm) emit pure red light. The optimized structure has been generated, and the HOMO–LUMO energy was calculated with the help of density functional theory (DFT). Due to the higher conjugation effect and lower HOMO–LUMO energy difference, TNB could be used as a supercapacitor electrode. In a three-electrode configuration, TNB has a maximum specific capacitance of 896.25 F/g. Furthermore, an asymmetric supercapacitor device (ASC) was fabricated in an aqueous electrolyte using TNB as a positive electrode having a high specific capacitance of 155 F/g. Even in an aqueous electrolyte, the ASC device reached the operating potential window of 0 to 1.4 V with an enhanced energy density of 42.19 W h/kg and ∼96% cyclic stability after 10 000 cycles. The reported oxazaborinine complex and its electrochemical efficiency in aqueous electrolytes make it ideal for supercapacitor applications and directly impact the development of advanced electrodes for next-generation supercapacitors

Mangiferin from <i>Enicostemma littorale</i> Blume with <i>in silico</i> and <i>in vitro</i> anti-inflammatory potential

The bioassay-guided fractionation of the extract of aerial parts of Enicostemma littorale resulted in two fractions 3 and 4 with moderate and potent antioxidant activity, respectively. The purification of fraction 3 gave swertiamarin (1), while the LCMS profile of fraction 4 unveiled the presence of another constituent along with swertiamarin. The extensive purification of fraction 4 led to the unusual isolation of mangiferin (2) from E. littorale. The uncommon isolation of mangiferin from E. littorale motivated us to conduct its in silico and in vitro screening as an anti-inflammatory agent. Both studies have proved mangiferin to be a promising anti-inflammatory molecule with a binding energy of −9.17 kcal/mol against Cyclooxygenase-2 protein and IC50 of 146.07 nanomolar. This study is the first report of the isolation of mangiferin, a xanthone glycoside from E. littorale. Communicated by Ramaswamy H. Sarma</p