Panchakot Mahavidyalya

Puruliya, India

Panchakot Mahavidyalya

Puruliya, India
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Guha A.,University of Calcutta | Banu K.S.,University of Calcutta | Das S.,University of Calcutta | Chattopadhyay T.,Panchakot Mahavidyalya | And 3 more authors.
Polyhedron | Year: 2013

Four new mononuclear nickel(II) complexes, namely [NiL1(H 2O)3](NO3)2 (1), [NiL 2(H2O)3](NO3)2 (2), [NiL3(H2O)3](NO3)2 (3) and [NiL4(ClBz)(H2O)]·1.25(H2O) (4) have been synthesized via Schiff-base formation by condensation between 2-benzoylpyridine and N-(2-aminoethyl)pyrrolidine for L1, salicylaldehyde and N-(2-aminoethyl)piperazine (L2), 5-chlorosalicylaldehyde and N-(2-aminoethyl)piperazine (L3), and 5-chlorosalicylaldehyde and N-(2-aminoethyl)morpholine (L4). These complexes are comprehensively characterized via routine physicochemical techniques as well as by single crystal X-ray structural analyses. Despite all the nickel complexes are mononuclear, the catecholase activity shows prominent variation depending on the coordination environment around the metal center. Complexes 2 and 3 derived from same amine bear an extra positive charge on the ligand system facilitating the substrate-catalyst interaction to promote the oxidation of 3,5-DTBC to 3,5-DTBQ. On the contrary complexes 1 and 4 remain inert in nature, although 1 shows structural similarities in terms of coordination environment with nickel substituted catechol oxidase.

Ghosh T.,University of Calcutta | Chattopadhyay T.,Panchakot Mahavidyalya | Das S.,University of Calcutta | Mondal S.,University of Calcutta | And 3 more authors.
Crystal Growth and Design | Year: 2011

Two pseudohalides thiocyanate and dicyanamide have been employed to synthesize complexes of MnII, CoII, NiII, CuII, and ZnII in the presence of a hemilabile ligand 2-benzoylpyridine (Phpyk). With thiocyanate all the aforesaid metal ions (except for CoII, of which suitable single crystals for X-ray analysis were not obtained) produce mononuclear complexes having general composition of [MII(NCS)2(Phpyk)2]. The structure determination reveals that Mn and Zn complexes (1, 4) are isomorphous and isostructural (crystallizing in space group C2/c), while Ni and Cu complexes (2, 3) crystallize in space groups P1̄ and P21/n, respectively. Interestingly, no complex has been obtained with a configuration having the N of one Phpyk trans to the O of the other chelating ligand and among the four complexes only in complex 3 the two thiocyanato ligands are in trans-configuration. On the other hand, complexes 5-8 are isomorphous and crystallize in orthorhombic chiral space group P21212 1. The bridging mode of dicyanamide anions helps to generate a three-dimensional covalently bonded polymeric network of 66 topology for all the polynuclear complexes. By using 8 as sole precursor, we have pyrolytically synthesized triangular shaped ZnO nanoparticles. © 2011 American Chemical Society.

Banerjee A.,University of Calcutta | Guha A.,University of Calcutta | Maiti A.,University of Calcutta | Goswami S.,University of Calcutta | And 5 more authors.
Transition Metal Chemistry | Year: 2011

Three Ni(II) complexes of cresol-based Schiffbase ligands, namely [Ni 2(L 1)(NCS) 3(H 2O) 2], (1) [Ni 2(L 2)- (CH 3COO)(NCS) 2(H 2O)] (2) and [Ni 2(L 3)(NCS) 3] (3), (where L 1 = 2,6-bis(N-ethylpyrrolidineiminomethyl)-4-methylphenolato, L 2 = 2,6-bis(N-ethylpiperidineiminomethyl)-4-methylphenolato and L 3 = 2,6-bis{N-ethyl-N-(3-hydroxypropyl iminomethyl)}-4- methylphenolato), have been synthesized and structurally characterized by X-ray single-crystal diffraction in addition to routine physicochemical techniques. Density functional theory calculations have been performed to understand the nature of the electronic spectra of the complexes. Complexes 1-3 when reacted with 4-nitrophenyl phosphate in 50:50 acetonitrile-water medium promote the cleavage of the O-P bond to form p-nitrophenol and smoothly convert 3,5-ditert- butylcatechol (3,5-DTBC) to 3,5-di-tert-butylquinone (3,5-DTBQ) either in MeOH or in MeCN medium. Phosphatase- and catecholase-like activities were monitored by UV-vis spectrophotometry and the Michaelis-Menten equation was applied to rationalize all the kinetic parameters. Upon treatment with urea, complexes 1 and 2 give rise to [Ni 2(L 1)(NCS) 2(NCO)(H 2O) 2] (1') and [Ni 2(L 2)- (CH 3COO)(NCO)(NCS)(H 2O)] (2') derivatives, respectively, whereas 3 remains unaltered under same reaction conditions. © Springer Science+Business Media B.V. 2011.

Maiti P.,University of Calcutta | Khan A.,University of Calcutta | Chattopadhyay T.,Panchakot Mahavidyalya | Das S.,University of Calcutta | And 5 more authors.
Journal of Coordination Chemistry | Year: 2011

Four water-soluble dinuclear Zn(II) complexes (1-4) of compartmental ligand L=2,6-bis(R-iminomethyl)-4-R′-phenolate (where R=N-ethylpiperidine or R=N-ethylpyrrolidine, R′=methyl or tert-butyl) have been synthesized, characterized, and their DNA cleavage activity and cytotoxicity toward HepG2 cancerous cells are evaluated. The dinuclear complexes are formed by a pentadentate-substituted phenolate ligand chelating the metal ions separated by ca 3.27 Å . Each metal is a distorted trigonal bipyramid, completing the coordination sphere through acetate. The X-ray structural determination of 2 shows that the complex is counterbalanced by half Zn(SCN) 4 2- (formulation [Zn 2L 2(CH 3CO 2) 2][(Zn(SCN) 4] 0.5), while in 1 and 3 two crystallographically-independent complexes are present in the unit cell with a Zn(SCN) 4 2-. Among the four complexes only the 4-tert-butyl-phenolato derivatives (3 and 4) show DNA cleavage activity in in-vivo conditions and appear to be promising toward metal complexes to be used as anticancer agents. The cytotoxicity of the complexes, investigated through MTT assay, suggests that 4 is a better choice as artificial nuclease. © 2011 Taylor & Francis.

Mondal S.,University of Calcutta | Chattopadhyay T.,Panchakot Mahavidyalya | Das S.,University of Calcutta | Maulik S.R.,Visva Bharati University | And 2 more authors.
Indian Journal of Chemistry - Section A Inorganic, Physical, Theoretical and Analytical Chemistry | Year: 2012

CdO and CdS nanocrystals have been prepared via simple thermal treatment of coordination polymers, viz., [Cd(dca)2(Mim)2]n and [Cd(SCN)2(Bim)2]n (where Bim and Mim are benzimidazole and 1-methylimidazole respectively) as precursors at 600-650 °C in air for 2 h. A variety of techniques like infrared spectroscopy, X-ray diffraction, scanning electron microscopy and thermal gravimetric analysis have been employed to carry out structural characterization of these nanoparticles. The optical band gap of these materials, estimated to be about 2.43 and 2.50 eV respectively, establish a relationship between energy band gap of bulk and nanomaterials. Photocatalytic reactivity of these nanomaterials are evaluated by studying the degradation of C. I. Reactive Yellow 84, a popular and widely used reactive dye in cotton industry.

Guha A.,University of Calcutta | Sanyal R.,University of Calcutta | Chattopadhyay T.,Panchakot Mahavidyalya | Han Y.,Japan National Institute of Advanced Industrial Science and Technology | And 2 more authors.
Journal of Molecular Structure | Year: 2013

Four specially designed Schiff bases 2-formyl-4-R-6-(3N-4- hydroxybenzoicacid)-iminomethyl-phenolato (where R = methyl/tert-butyl/chloro for L1, L2, L3 respectively) and 2-(3N-4-hydroxybenzoicacid)-iminomethyl- phenolato (L4) having ability to form hydrogen bonding and their zinc complexes (1-4) have been synthesized and characterized. These complexes gave various types of nano-sized materials via self-assembly in solid state. FE-SEM was employed to investigate their morphology. Using a variety of analytical techniques such as elemental analysis, infrared spectroscopy (FT-IR), ESI-MS and 1H NMR spectroscopy, a consistent picture of structures of these complexes are obtained. All the Schiff-bases and their zinc complexes exhibit photoluminescence property. Density functional theory calculation has been performed to rationalize the origin of the spectral bands of the ligands as well as the complexes. © 2013 Elsevier B.V. All rights reserved.

Mondal S.,University of Calcutta | Chattopadhyay T.,Panchakot Mahavidyalya | Neogi S.K.,University of Calcutta | Ghosh T.,University of Calcutta | And 2 more authors.
Materials Letters | Year: 2011

A coordination polymer, Na2Cd2I6L 2(H2O)6 [L = Urotropine] has been employed as sole precursor to synthesize CdO particles. Two different preparation methods viz (i) pyrolysis of the title compound at 700°C for 2 h and (ii) forming cadmium hydroxide from the title compound followed by pyrolysis at 700°C for 2 h have been used for the synthesis of nano sized CdO-I and CdO-II, respectively. From powder XRD data the lattice parameters (0.4701 and 0.4696 nm respectively for the two samples) and particle size (~ 77 and 30 nm for CdO-I and CdO-II) have been evaluated. Morphology of the two varieties of CdO is widely different as is evident from their SEM images. The estimated values of the band gap of 2.53 eV and 2.59 eV for CdO-I and CdO-II respectively are obtained from the optical spectral analysis. © 2010 Elsevier B.V.

Chattopadhyay T.,Panchakot Mahavidyalya | Chattopadhyay T.,Japan National Institute of Advanced Industrial Science and Technology | Kogiso M.,Japan National Institute of Advanced Industrial Science and Technology | Aoyagi M.,Japan National Institute of Advanced Industrial Science and Technology | And 3 more authors.
Green Chemistry | Year: 2011

Organic nanotubes self-assembled from lipid compounds facilitate the synthesis of a new nano-catalyst with nickel ions. The nickel ions were fixed on the surface of the organic nanotubes through coordination. The nanotubes catalyzed oxidation of a wide range of organic compounds with hydrogen peroxide without organic solvent, and are reusable in at least five cycles without loss of activity. © 2011 The Royal Society of Chemistry.

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