• RAJEEV GUPTA

      Articles written in Journal of Chemical Sciences

    • Modelling tyrosinase monooxygenase activity. Activation of dioxygen by dicopper(I) complexes and characterisation of dicopper(II) complexes

      Rajeev Gupta Debalina Ghosh Rabindranath Mukherjee

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      Activation of dioxygen on dicopper(I) centres was systematically investigated using a group of open-chain and a macrocyclicm-xylyl-based dinucleating ligand from a bioinorganic viewpoint. Even though intermediate peroxodicopper(II) species was not detected (even at −80°C for the open-chain system), the putative intermediate reacted with C–H groups in ligands giving oxygenated products (C–OH groups). Absorption, spectroscopic and magnetic properties of the final dicopper(II) complexes have been investigated.

    • Effect of chelate-ring over the stabilization of copper-dioxygen adducts

      Rajeev Gupta Rabindranath Mukherjee

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    • Lewis acidic metal catalysed organic transformations by designed multi-component structures and assemblies

      Afsar Ali Amit P Singh Rajeev Gupta

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      This paper presents the recent developments in designing multi-component structures including metal-organic frameworks containing Lewis acidic metal ions. The emphasis has been given to understand the design elements adopted to synthesize such structures bearing Lewis acidic metal ion. Further, few important Lewis acidic metal catalysed organic transformation reactions have been discussed demonstrating the importance of such materials for practical purposes.

    • Syntheses, characterization, and anti-cancer activities of pyridine-amide based compounds containing appended phenol or catechol groups

      Afsar Ali Deepak Bansal Nagendra K Kaushik Neha Kaushik Neha Kaushik Eun Ha Choi Rajeev Gupta

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      Several pyridine-amide compounds appended with phenol/catechol groups are synthesized. These compounds consist of protected or deprotected phenol/catechol groups and offer pyridine, amide, and phenol/catechol functional groups. All compounds have been well-characterized by various spectroscopic methods, elemental analysis, thermal studies, and crystallography. The biological activities of all compounds were investigated while a few compounds significantly decreased the metabolic viability, growth and clonogenicity of T98G cells in dose dependent manner. Accumulation of ROS was observed in T98G cells, which displayed a compromised redox status as evident from increased cellular Caspase 3/7 activity and formation of micronuclei. The in silico pharmacokinetic studies suggest that all compounds have good bioavailability, water solubility and other drug-like parameters. A few compounds were identified as the lead molecules for future investigation due to their: (a) high activity against T98G brain, H-460 lung, and SNU-80 thyroid cancer cells; (b) low cytotoxicity in non-malignant HEK and MRC-5 cells; (c) low toxic risks based on in silico evaluation; (d) good theoretical oral bioavailability according to Lipinski ‘rule of five’ pharmacokinetic parameters; and (e) better drug-likeness and drug-score values.

    • Coordination driven architectures based on metalloligands offering appended carboxylic acid groups

      GULSHAN KUMAR RAJEEV GUPTA

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      The field of coordination polymers (CPs) has grown rapidly in the recent time and exemplifies one of the most exciting fields in the solid state and structural chemistry. In order to search for new CPs with desirable structural features and attractive functional properties, various synthetic strategies have been adopted including the challenging metalloligand approach. This approach relies on developing a metalloligand that is capable of placing the appended functional groups to limited directions thus resulting in limited structural variations—alandmark step towards predictable architectures. Consequently, a variety of metalloligands offering assorted functional groups have been developed and explored for the construction of noteworthy CPs. This perspective article summarizes an important class of metalloligands offering appended carboxylic acid groups with a focus on the design strategies to understand the architectures of the resultant CPs being controlled by the metalloligands. In addition, a concise discussion has been included about the applications of selected CPs to demonstrate their practical utilization.

    • Selective turn-on sensing of fluoroquinolone drugs by zinc complexes of amide-based ligands

      DIVYA PRABHA DEVENDER SINGH RAJEEV GUPTA

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      This work presents two mononuclear Zn(II) complexes of amide-based pincer ligands wheremigration of protons from the amidic N–H groups to the appended heterocyclic rings resulted in theirprotonation. The crystal structures of both the zinc complexes illustrated that such protonated heterocyclicrings created an H-bonding based secondary coordination sphere. Both complexes were utilized for theselective detection of fluoroquinolone antibiotics ciprofloxacin and norfloxacin. The two complexes exhibitedhigh selectivity for norfloxacin with nanomolar detection limits of 290 and 460. The binding studies werefurther supported with the NMR spectroscopic and the molecular docking studies that exhibited that anantibiotic interacts with a zinc complex that was responsible for its emission enhancement based detection.

      Synopsis This work presents two structurally characterized zinc complexes of amide-based ligands and their role in the selective detection of fluoroquinolone antibiotics ciprofloxacin and norfloxacin.

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