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Silchar, India

Bhattacharjee C.R.,Assam University | Goswami P.,Silchar Polytechnic | Sengupta M.,Assam University
Journal of Coordination Chemistry | Year: 2010

Tridentate Schiff bases (H 2L 1 or H 2L 2) were derived from condensation of acetylacetone and 2-aminophenol or 2-aminobenzoic acid. Binuclear square pyramidal complexes of the type [M 2(L 1) 2] nH 2O (M = Fe-Cl, n = 0; M = VO, n = 1) were accessed from interaction of H 2L 1 with anhydrous FeCl 3 and VOSO 4 5H 2O, respectively. A similar reaction with H 2L 2, however, produced mononuclear complexes [ML 2(H 2O) x] nH 2O (M=Fe-Cl, x = 0, n = 0; M=VO, x = 1, n = 1). The compounds were characterized using elemental analysis, FT-IR, UV-Vis, and NMR (for ligand only), and mass spectroscopies and solution electrical conductivity studies. Magnetic susceptibility measurements suggest antiferromagnetic exchange in binuclear Fe(III) and VO(IV) complexes. Thermo gravimetric analysis (TGA) provided unambiguous evidence for the presence of coordinated as well as lattice water in [VOL 2(H 2O)] H 2O. Cyclic voltammetric studies showed well-defined redox processes corresponding to Fe(III)/Fe(II) and VO(V)/VO(IV). Invitro antimicrobial activities of the compounds were investigated against Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeroginosa, Escherichia coli, Bacillus subtilis, and Proteus vulgaris. H 2L 1 and its binuclear complexes exhibited pronounced activity against all the microorganisms tested. © 2010 Taylor & Francis. Source


Barbhuiya A.K.,National Institute of Technology Silchar | Mazumder M.H.,Silchar Polytechnic
ISH Journal of Hydraulic Engineering | Year: 2014

Local scour experiments were performed with four different uniform cohesionless sediment diameters d50 = 0.26, 0.42, 1.06, and 1.92 mm and five vertical-wall abutments with projected lengths l = 0.04, 0.06, 0.08, 0.10, and 0.12 m perpendicular to the flow. These tests were conducted at different flow velocity (V) varying from 0.71 to 5 times of the critical velocity (Vc). The plotting of scour depths dse vs. V/Vc shows that the scour depths increase up to the threshold value of flow (V/Vc = 1) and after that it reduces and again increases to attain the live-bed maximum in the flow range V/Vc = 3-5. It is observed that the scour depth increases with the increase of sediment sizes and abutment lengths. Further, the scour depth decreases with the increases of nonuniformity under all flow conditions. A design equation is proposed based on the present experimental data and existing live-bed scour data. The measured values of scour depth are compared with the calculated values using proposed equation and also with three different live-bed local scour equations for the conditions of the tests. © 2014 Indian Society for Hydraulics. Source


Bhattacharjee C.R.,Assam University | Goswami P.,Silchar Polytechnic | Pramanik H.A.R.,Assam University | Paul P.C.,Assam University | Mondal P.,Assam University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

Two new mixed-ligand iron(III) complexes, [Fe(L n)(acac)(C 2H 5OH)] incorporating coordinated ethanol from the reaction solvent were accessed from the reaction of [Fe(acac) 3] with [ONO] donor dibasic tridentate unsymmetrical Schiff base ligands derived from condensation of 2-hydroxy-1-napthaldehyde with 2-aminophenol (H 2L 1) or 2-aminobenzoic acid (H 2L 2). The thermal study (TGA-DTA) provided evidence for weakly bound ethanol which is readily substituted by neutral N-donor molecule imidazole, benzimidazole or pyridine to produce an array of newer complexes, [Fe(L n)(acac)X] (n = 1, 2; X = Im, Bim, Py). The compounds were characterized by elemental analyses, FT-IR, UV-vis, solution electrical conductivity, FAB mass, 1H and 13C NMR spectroscopy. Room temperature magnetic susceptibility measurements (μ eff ∼ 5.8 B.M.) are consistent with spin-free octahedral iron(III) complexes. Cyclic voltammetry of ethanol complexes revealed a quasi-reversible one electron redox response (ΔE p > 100 mV) for the Fe(III)/Fe(II) couple. Low half wave redox potential (E 1/2) values suggested easy redox susceptibility. The ground state geometries of the ethanol and imidazole complexes have been ascertained to be distorted octahedral by density functional theory using DMol3 program at BLYP/DNP level. © 2011 Elsevier B.V. All rights reserved. Source


Tripathy B.C.,Institute of Advanced Study in Science and Technology | Sen M.,National Institute of Technology Silchar | Nath S.,Silchar Polytechnic
Soft Computing | Year: 2012

In this article we introduce the notion of I-Cauchy sequence and I-convergent sequence in probabilistic n-normed space. The concept of I*-Cauchy sequence and I*-convergence in probabilistic n-normed space are also introduced and some of their properties related to these notions have been established. © 2012 Springer-Verlag. Source


Bhattacharjee C.R.,Assam University | Goswami P.,Silchar Polytechnic | Mondal P.,Assam University
Inorganica Chimica Acta | Year: 2012

Cationic iron(III) complexes of the type [FeL n(H 2O) 2]NO 3 (n = 1 or 2) were accessed from the interaction of Fe(NO 3) 3·9H 2O with [N 2O 2] donor Schiff base (L) in 1:1 molar ratio. The Schiff base ligands were prepared from condensation of 2-hydroxy-1- naphthaldehyde with o-phenylenediamine or ethylenediamine in 2:1 molar ratio. Reaction of the aquated complexes with neutral N-donor molecules (X) viz. imidazole, benzimidazole and pyridine led to substitution of weakly held axial aquo groups affording new mixed ligand complexes, [FeL nX 2]NO 3. The compounds were characterized by elemental analyses, FT-IR, UV-Vis, solution electrical conductivity, FAB mass, 1H and 13C NMR (ligands only) spectroscopy. The thermal study provided unambiguous evidence for the occurrence of coordinated water in the complexes. Room temperature magnetic susceptibility measurements are consistent with high spin octahedral iron(III) complexes. Cyclic voltammetry revealed a quasi-reversible one electron redox response (ΔE p > 100 mV) assignable to Fe(III)/Fe(II) couple with negative half wave potential. The ground state geometries of the aquo complex, [FeL 2(H 2O) 2]NO 3 and pyridine complex, [FeL 2(Py) 2]NO 3 were ascertained by density functional theory using dmol3 program with BLYP functional. © 2012 Elsevier B.V. All rights reserved. Source

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