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Mallick A.,Kashipur Michael Madhusudan Mahavidyalaya | Roy U.K.,Deshabandhu Mahavidyalaya | Haldar B.,Vivekananda Mahavidyalaya | Pratihar S.,Indian Institute of Technology Bhubaneswar
Analyst | Year: 2012

A new easy-to-synthesize chemosensor, 3,3′-bis(indolyl)-4- chlorophenylmethane (hereafter S), was designed, synthesized and employed as a selective optical chemosensor for fluoride ions. 1H NMR and density functional studies on the system have been carried out to determine the nature of the interaction between S and X - (X = inorganic anions) responsible for the significant fluoride-induced changes in the absorption properties of S. The experimental results reveal that abstraction of an acidic proton of S by the fluoride ion, leading to the formation of anionic species, is responsible for the spectral changes. These changes allow signaling for the fluoride ion to detect and estimate the concentration of fluoride ion present even at the submicromolar level, accurate up to 2 μM. Calculations of the transition energies of S, S -, and S⋯F - (hydrogen bonded complex) show that only S - is responsible for the long-wavelength absorption band in the presence of F -. This journal is © The Royal Society of Chemistry 1212.


Sarkar D.,Jadavpur University | Mallick A.,Kashipur Michael Madhusudan Mahavidyalaya | Haldar B.,Vivekananda Mahavidyalaya | Chattopadhyay N.,Jadavpur University
Chemical Physics Letters | Year: 2010

An alternative strategy, hybridizing the proper choice of a pH sensitive fluorophore and the ratiometric technique of plot of the spectral parameters of the probe, has been introduced for the generation of new molecular sensors for multidimensional purposes. Various anions present in aqueous medium or biological fluids through alkali metal salts, can be detected and estimated. Selectivity factor turns out to be dependent on the dissociation constant of the conjugate acid of the anion to be detected. The technique can be exploited for the sensing of cyanide ion, a supremely toxic anion, accurate to the micromolar level of concentration. © 2009 Elsevier B.V. All rights reserved.


Roy S.,Shibpur Dinobundhoo Institution College | Mondal P.,Vivekananda Mahavidyalaya | Sengupta P.S.,Vivekananda Mahavidyalaya | Dhak D.,Sidho Kanho Birsha University | And 3 more authors.
Dalton Transactions | Year: 2015

A 1:2 copperII complex of 1-amino-4-hydroxy-9,10-anthraquinone (QH) having the molecular formula CuQ2 was prepared and characterized by elemental analysis, NMR, FTIR, UV-vis and mass spectroscopy. The powder diffraction of the solid complex, magnetic susceptibility and ESR spectra were also recorded. The presence of the planar anthraquinone moiety in the complex makes it extremely difficult to obtain a single crystal suitable for X-ray diffraction studies. To overcome this problem, density functional theory (DFT) was used to evaluate an optimized structure of CuQ2. In the optimized structure, it was found that there is a tilt of the two planar aromatic anthraquinone rings of the complex with respect to each other in the two planes containing the O-Cu(ii)-O plane. The present study is an important addition to the understanding of the structural aspects of metal-anthracyclines because there are only a few reports on the actual structures of metal-anthracyclines. The theoretical vibrational spectrum of the complex was assigned with the help of vibrational energy distribution analysis (VEDA) using potential energy distribution (PED) and compared with experimental results. Being important in producing the biochemical action of this class of molecules, the electrochemical behavior of the complex was studied in aqueous and non-aqueous solvents to find certain electrochemical parameters. In aqueous media, reduction involves a kinetic effect during electron transfer at an electrode surface, which was characterized very carefully using cyclic voltammetry. Electrochemical studies showed a significant modification in the electrochemical properties of 1-amino-4-hydroxy-9,10-anthraquinone (QH) when bound to CuII in the complex compared to those observed for free QH. This suggests that the copper complex might be a good choice as a biologically active molecule, which was reflected in the lack of stimulated superoxide generation by the complex. This journal is © The Royal Society of Chemistry 2015.


Mondal P.,Vivekananda Mahavidyalaya | Saha S.K.,Visva Bharati University | Chowdhury P.,Visva Bharati University
Journal of Applied Polymer Science | Year: 2013

Quantitative polymerization of 4-vinyl pyridine (4-VP) and its quaternization has been done simultaneously for the first time in absence of organic solvents. 1, 4-dibromo-2-butene acts as quaternizing agent. The quaternized polymer has been characterized by chemical, thermal and spectral analysis. The mechanistic path involved in the polymerization and quaternization has been elucidated. Particle size, surface area, ion exchange capacity and metal ion binding property were determined. The polymer was found to have pH-dependent chromate ion binding capacity with high level of selectivity and good antibacterial activity. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 Copyright © 2012 Wiley Periodicals, Inc.


Sharma K.,Vivekananda Mahavidyalaya | Sharma S.P.,Central Forensic Science Laboratory | Lahiri S.C.,Central Forensic Science Laboratory
Alcohol | Year: 2010

Numerous methods like distillation followed by iodometric titrations, gas chromatograph (GC)-flame ionization detector, gas chromatograph-mass spectrophotometer, GC-Headspace, Breath analyzer, and biosensors including alcohol dehydrogenase (enzymatic) have been used to determine blood alcohol concentration (BAC). In the present study, horizontal attenuated total reflectance-Fourier transform infrared spectroscopy had been used to determine BAC in whole blood. The asymmetric stretching frequency of C-C-O group of ethanol in water (1,045cm-1) had been used to calculate BAC using Beer's Law. A seven-point calibration curve of ethanol was drawn in the concentration range 24-790mg dL-1. The curve showed good linearity over the concentration range used (r2=0.999, standard deviation=0.0023). The method is accurate, reproducible, rapid, simple, and nondestructive in nature. © 2010 Elsevier Inc.


Mukhopadhyay A.,Vivekananda Mahavidyalaya
Acta Mechanica | Year: 2011

A thin viscous liquid film flowing down a rotating non-uniformly heated inclined plane is investigated. It is assumed that the rotation is small and the region of investigation is very far from the axis of rotation, so that the centrifugal force has a dominant role in the instability of the investigated region. Therefore, we have derived a Benney-like free surface evolution equation on the basis of a long-wave (small wave number) approximation and not included the Coriolis effects in the expansion of the dependent variables. Further, a linear and a weakly nonlinear study have been carried out. The linear study reveals that the growth of linear perturbation is independent of the Rossby number Ro, that is invariant with the Coriolis effect, while the linear phase speed c r depends on Ro as well as on the Taylor number Ta. It also reveals that as Ta increases the stable zone decreases, and the influence of Ta is stronger for greater inclination of the rotating inclined plane. Again, it is found that the Marangoni number Mn has similar qualitative (destabilizing) behavior as Ta, but the destabilizing behavior of Ta is more at high Mn than at low Mn. The relation between the parameters Ta and Ro gives a unified parameter Tarot, which reflects the effect of rotation, and we found that the linear phase speed c r first decreases with Tarot up to a critical value and then increases with Tarot. This is due to the fact that the Coriolis force is dominant at very small rotation, while for relatively large rotation the centrifugal force dominates the flow field. The weakly nonlinear study reveals that the effect of rotation appears in the form of both Coriolis and centrifugal force into the growth of finite amplitude perturbations in contrast to the growth of the infinitesimal perturbations where the rotation arrives in the form of centrifugal force only. Also, it plays significant role in the different stability zones, amplitudes of sub/super critical disturbances and nonlinear phase speed. © 2010 Springer-Verlag.


Banerjee S.,Darjeeling Government College | Banerjee S.,University of Burdwan | Sengupta P.S.,Vivekananda Mahavidyalaya | Mukherjee A.K.,University of Burdwan
Chemical Physics Letters | Year: 2010

A hydrolysis process of the third generation orally active anticancer drug cis-[PtCl2(NH3)(2-picoline)], ZD0473 has been investigated using density functional theory. Pentacoordinated platinum transition state (TS) geometries along with other stationary points on potential energy surface were optimized and characterized including two different paths. Two explicit water molecules were included in the calculations to improve the solvation energies. To obtain accurate energies for the reaction surfaces, single-point energies were calculated by conductor-like polarisable continuum model (CPCM) using larger basis sets. The calculated results show that the second step is the rate-limiting process. The computed values of rate constant of different steps are in good agreement with the available experimental results. © 2010 Elsevier B.V. All rights reserved.


Mukhopadhyay A.,Vivekananda Mahavidyalaya | Haldar S.,Hooghly Womens College
Zeitschrift fur Naturforschung - Section A Journal of Physical Sciences | Year: 2010

The two dimensional flow of a viscoelastic fluid (weakly elastic) represented byWalters' B" model running down an inclined heated plane with linear temperature variation has been investigated in the finite amplitude regime. A long-wave expansion method obtains a nonlinear evolution equation of the filminterface. A normal mode approach and the method of multiple scales are used to obtain the linear and nonlinear stability solutions for the film flow. The study reveals that both supercritical stability and subcritical instability are possible for this type of film flow. The influence of the viscoelastic parameter and the Marangoni number on the different zones, the amplitude of the disturbances on sub/supercritical region, and the nonlinear phase speed in the supercritical region are also investigated. It is interesting to note that the influence of the viscoelastic parameter on the above aspects are very significant at low Marangoni number, while it has very feeble impact at high Marangoni number. Finally, the results thus determined are interpreted physically. © 2010 Verlag der Zeitschrift für Naturforschung, Tübingen.


Sharma K.,Vivekananda Mahavidyalaya | Lahiri S.C.,Central Forensic Science Laboratory
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

1,3-Dinitrobenzene formed colored 1:1 complexes with aliphatic amines (chromogenic agents) like isopropylamine,ethylenediamine, tetraethylenepentamine and bis(3-aminopropyl)amine in DMSO having absorption maxima at 563 nm, 584 nm, 580.5 nm and 555 nm respectively. The complexes were stable for more than 24 h. The accurate association constants K AD and other thermodynamic parameters were determined with D and A usually in stoichiometric ratios. But in case of m-DNB and bis(3-aminopropyl)amine, the association constants K AD and the thermodynamic parameters were also determined using Benesi-Hildebrand equation to show the variations of K AD under different conditions. ΔG° values were found to be negative in all cases resulting from exothermic enthalpy changes and favourable entropy changes. The energies of transition for the CT complexes hν CT found experimentally were considerably different from the energies of transition (from HOMO of donor to LUMO of acceptor) calculated using AM1 but the differences were considerably reduced using DFT calculations. The vertical electron affinity of m-DNB was calculated using the method suggested by Mulliken. However, no FTIR measurements of the complexes could be made due to experimental limitations. © 2011 Elsevier B.V. All rights reserved.


Methyldopa is a much used antihypertensive drug. It is the subject matter of study mostly for the determination and estimation of methyldopa in pharmaceutical properties. These considerations led us to study the charge-transfer interactions between methyldopa, a centrally acting antihypertensive agent of limited use with the known acceptors like o-chloranil (o-ClN), chloranilic acid (ClA) and dichlorodicyanobenzoquinone (DDQ). Methyldopa (MDP) formed beautifully colored complexes (having absorption maxima at 581 nm and 368 nm; 519 nm; 583.5 nm, 547 nm and 346 nm, respectively) with the acceptors mentioned before. The physico-chemical properties of the complexes were studied using UV-visible spectrophotometry and FTIR measurements. The composition, the accurate association constants and thermodynamics of the complexes were determined spectrophotometrically. Attempts were made to interpret the thermodynamics of complexes in terms of IDV, EAV and hν CT. Solid CT complexes between MDP + o-ClN, MDP + ClA and MDP + DDQ were prepared and FTIR spectra of the complexes were studied. The energies hν CT of the charge-transfer complexes and vertical ionization potential IDV of methyldopa were compared with the theoretical values of hν CT obtained from HOMO and LUMO of the donors and acceptors calculated using Density Function Theory utilizing different basis sets. The agreement between the results can be regarded to be reasonable. Oscillator strengths and dipole strengths of the complexes were determined theoretically and experimentally and the limitations of the calculations were outlined. © 2012 Elsevier B.V. All rights reserved.

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