http://dspace.cus.ac.in/jspui/handle/1/6343 2026-04-13T15:24:14Z http://dspace.cus.ac.in/jspui/handle/1/6427 Title: Synthesis, structures and catalase activities of bis(μ-oxo)diMnIII,III and bis(μ- acetato)diMnII,II complexes bearing a quinolyl donor tripod ligand Authors: Biswas, Sachidulal; Das, Purak; Rasaily, Sagarmani; Pariyar, Anand; Biswas, Achintesh Narayan Abstract: The syntheses and characterization of two new complexes, [Mn2(TQA)2(µ-O)2](ClO4)2 (1) and [Mn2(TQA)2(µ-OAc)2](ClO4)2 (2) (TQA = tris(2-quinolylmethyl)amine), are described. The diMn complexes (1 & 2) have been characterized by elemental analysis, IR and X-ray diffraction. The complexes partly resemble the active-site structures of the oxidized and reduced forms of bacterial manganese catalases. Addition of aqueous H2O2 to the complexes in 1:1 MeOH/tris-buffer solution led to rapid evolution of O2 confirming their catalase activity. The complexes 1 & 2 exhibited turnovers of 810 and 665 mol O2 per mol of the catalysts, respectively. Catalytic efficiencies (kcat/KM) of 8.5 and 22 M−1 s−1 were measured for the complexes 1 & 2. The corresponding mononuclear Mn(II) complex, [Mn(TQA)(MeCN)(ClO4)](ClO4)·MeCN (3) also exhibited similar catalase activity. The complexes (1–3) showed marked preference for catalytic H2O2 disproportionation over oxidation of 2,2′-azinobis-(3-ethylbenzothiazoline)-6-sulfonicacid (ABTS). 2019-01-01T00:00:00Z http://dspace.cus.ac.in/jspui/handle/1/6401 Title: Vibrational, energetic-dynamical and dissociation properties of water clusters in static electric fields: non-equilibrium molecular-dynamics insights Authors: Chakraborty, Somendra Nath; English, Niall J. Abstract: Water clusters are hydrogen bonded molecular assembly of water molecules. They have been extensively studied using experiments, ab initio calculations and molecular simulations. The molecular arrangement of water in water cluster provide significant insights into behavior of water in bulk, confinement and close to surfaces. Here molecular dynamics simulations of TIP4P/2005 water clusters are performed in weak electrid fields. These fields introduce additional forces of varying magnitude 0.1–25 of forces existing in without-field water clusters. Autocorrelation functions of distance, energy and velocities are analysed. Molecular arrangements in water clusters does not disintegrate under additional forces. 2018-01-01T00:00:00Z http://dspace.cus.ac.in/jspui/handle/1/6397 Title: In situ mechanochemical synthesis of nitrones followed by 1,3-dipolar cycloaddition: a catalystfree, “green” route to cis-fused chromano[4,3-c] isoxazoles Authors: Bhutia, Zigmee T.; P., Geethika; Malik, Anurag; Kumar, Vikash; Chatterjee, Amrita; Roy, Biswajit Gopal; Banerjee, Mainak Abstract: An efficient and catalyst-free method for the synthesis of cis-fused chromano[4,3-c]isoxazoles via intramolecular 1,3-dipolar nitrone cycloaddition involving hand-grinding in a mortar-pestle has been developed. The mechanochemical agitation was sufficient for dehydrative nitrone formation by condensation of various O-allyl salicylaldehyde derivatives and alkyl/aryl hydroxylamines. The corresponding nitrones undergo intramolecular 1,3-dipolar cycloaddition leading to regioselective formation of cis-fused tetrahydrochromeno[4,3-c]isoxazole derivatives in high yields. The key features of this new method are cleaner reaction profiles, catalyst-free conditions, high yields, and short reaction times. 2015-01-01T00:00:00Z http://dspace.cus.ac.in/jspui/handle/1/6396 Title: Recognition of fluoride anions at low ppm level inside living cells and from fluorosis affected tooth and saliva samples Authors: Ghosh, Pritam; Roy, Biswajit Gopal; Mukhopadhyay, Subhra Kanti; Banerjee, Priyabrata Abstract: A simple Schiff base chemosensor 2-((2-(2,4-dinitro phenyl)hydrazono)methyl)-4-nitrophenol (L) has been developed as a colorimetric and fluorimetric ‘turn on’ sensor for fluoride (F−). F− recognition at ppm levels from mouth rinses and a toothpaste water solution has been successful. Significantly, L can detect F− from fluorosis affected tooth and saliva samples by similar colorimetric changes. A test kit for F− detection from a DMSO–water (1 : 1) mixture is also engineered. Intracellular F− from pollen grains of Techoma stans and Candida albicans (a diploid fungus), grown in 10−6 (M) F− contaminated water has been successfully detected under a fluorescence microscope. 2015-01-01T00:00:00Z