Gulshan Kumar

The present study focused on the single-pot synthesis of polyaniline (PANI) and the polyaniline-pyrrole (PANI-Py) copolymer via chemical oxidative polymerisation, their characterization and biological applications

An ESIPT-active 8-hydroxyquinoline-based fluorescent chemosensor, HQHBI, has been synthesized for the sensitive detection of the nerve-agent simulant diethyl chlorophosphate (DCP). The probe exhibits a low detection limit of 1.5 × 10⁻⁷ M and demonstrates excellent selectivity in the presence of a wide range of competing anions. Photophysical studies in different solvents reveal the involvement of ESIPT and ICT processes, while pH titrations confirm its operational stability under physiological and environmental conditions. The sensing mechanism is further validated through time-resolved fluorescence and NMR titration studies, indicating selective interaction via the phenolic –OH group. Additionally, DFT and TD-DFT calculations support the experimental findings by elucidating key electronic transitions responsible for the sensing response. Notably, HQHBI also enables molecular logic gate operations, highlighting its potential in chemical information processing.

The pharmacologic anti-inflammatory drug diclofenac sodium (DCF) is widely used for pain management across various medical treatments and discarded into waterways without proper treatment, polluting them. Conventional methods for degrading DCF have drawbacks, including hydrophobicity, limited thermal stability, and insufficient mechanical strength. In this work, polyurethane (PU) has been extracted from waste plastic and modified by MnO₂ NPs to fabricate a polyurethane/MnO₂ (PU/MnO₂) modified polymeric membrane (MPM). The photocatalytic degradation of DCF was studied using UV-visible spectroscopy. The optimum conditions were as follows: a solution pH of 4, an H₂O₂ concentration of 1 mL, a DCF solution concentration of 5 mg L⁻¹, and MnO₂ NPs (0.4 g) incorporated into a polymeric membrane; under these conditions, 95% degradation of DCF was achieved within 240 min. Additionally, PMs exhibit antioxidant properties due to their ability to scavenge DPPH (2,2-diphenyl-1-picrylhydrazyl) free radicals. DFT (density functional theory) calculations also supported the degradation study by illustrating the interaction between the MPM and DCF. Seed germination of Vigna radiata was done using treated water with a modified polymeric membrane, which showed a positive growth response. This study provides a novel method for developing a polymeric membrane from waste plastic, which can then be used for the photocatalytic degradation of DCF in water sources.

This article represents the development of a novel synthetic route towards the synthesis of s-triazine derivatives bearing benzimidazole and 1,2,4-oxadiazole cores (compounds 2-8a, b), which are interconnected through N- and O-spacers, via a nucleophilic substitution approach facilitated by C-N bond activation, using Pd(II) acetate as a catalyst. This methodology involves use of synthons such as imidate ester and oxime, towards synthesizing s-triazine derivatives. All synthesized compounds were characterized using 1H NMR, 13C NMR, and IR spectroscopy and validated through in-silico studies concerning cervical cancer. Density Functional Theory (DFT) study results showed that several factors should be considered when evaluating the suitability of the compounds studied as candidates for strong binding with proteins. For compounds 6b, 6d, and 8a the DFT results provided pronounced support for the in-silico and molecular docking studies. The Pd(II)-acetate-catalysed approach highlights the strategic utility of transition metal catalysis in constructing complex multi-heterocyclic framework that combine three biologically relevant pharmacophores within a single molecule, providing efficient access to diverse compounds with potential therapeutic applications in medicinal chemistry.

Selective binding of Ga ³⁺ and DCP inhibiting ESIPT leading to enhanced keto-state emission and a distinct fluorescence turn-on signal.

A bis-naphthalimide-based “turn-on” fluorescent chemosensor, BINNA is developed, capable of dual-analyte recognition with sensitivity and selectivity for aluminium ions (Al ³⁺ ) and nerve agent mimic diethyl chlorophosphate (DCP) in methanol medium.

Leaves of Cucumis callosus, traditionally employed in Ayurvedic medicine for the treatment of urinary disorders, were investigated in depth for their therapeutic potential against bacterially induced urinary tract infection (UTI) for the first time. The present work is the first to explore the antibacterial activity of C. callosus leaf fractions with an integrative in silico, in vitro, and in vivo approach. Through bioassay-guided fractionation, the chloroform fraction (F1) was identified as the most active, exhibiting potent activity against Uropathogenic Escherichia spp. species. Liquid chromatography–mass spectrometry (LC-MS) analysis of F1 revealed the presence of bioactive compounds, including stigmasterol, 1,2,3,4-tetrahydroisoquinoline, lactose, hydroxy(mesityl)acetic acid, and 2,4-di-tert-butylphenol. Molecular docking studies validated the strong binding affinities of these compounds for bacterial resistance enzymes, including AmpC β-lactamase and carbapenemases, thereby providing plausible mechanisms of antimicrobial action. In vivo studies carried out on female rats infected with Escherichia spp. species revealed a dose-dependent reduction in bacterial load, with a significant decrease in urinary tract inflammation upon F1 administration. Histopathological evaluation confirmed the protective effect, with reduced epithelial damage and inflammation in bladder tissues. These findings indicate significant antibacterial and tissue-protective effects of the C. callosus leaf fraction F1, supporting its ethnomedicinal use and establishing it as a promising phytotherapeutic agent for the treatment of urinary tract infections.

The present investigation employs the chemical oxidative polymerization approach to synthesize co-doped polyaniline (PANI) and polyaniline-co-pyrazine (PANI-co-Pyr) in a single pot for antimicrobial applications.

The excited-state intramolecular proton transfer (ESIPT) dynamics of the ratiometric fluorescent benzimidazole-conjugated aminomalanitrile-based probe 1, an asymmetric structure synthesized by Gong et al. (RSC Adv. 2019, 9, 30943–30951), were investigated using density functional theory (DFT) and time-dependent DFT (TDDFT) methods. The presence of strengthened dual-facet hydrogen bonds in the excited state, along with charge redistribution, facilitates the ESIPT process. The geometrical optimization of six conformations identified C3 and C4 as the most stable at S₀ state (58.8% and 33.6%, respectively). Theoretical calculations align well with experimental absorption spectra and excitation values within the 350–425 nm range. FTIR analysis confirmed enhanced intramolecular hydrogen bonding (intraHBs) in C3 and C4, evidenced by redshifts and reduced interaction distances. The relative free energy profiles of tautomeric forms indicate stable states in S₀ and S₁, with low energy barriers enabling proton transfer in the excited state. The vertical emission peaks closely match experimental spectra, underscoring the role of dual-facet hydrogen bonding in photophysical behaviour. The S₁-state potential barriers suggest an excited-state single proton transfer (ESPT) rather than a double proton transfer. Upon OCl⁻ addition, the ESIPT process remains uninhibited in probe 1, confirming its OCl⁻ sensing mechanism via imidazole derivative formation. This study not only elucidates the ESIPT mechanisms of probe 1 but also enhances the understanding of HOCl detection, contributing to the development of novel fluorescent probes.