@rammohancollege.ac.in
Assiostant Professor, Department of Chemistry, Rammohan College
Rammohan College
Chemistry, Inorganic Chemistry, Analytical Chemistry, Biochemistry
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Arup Mandal, Sumon Ray, Animesh Chattopadhyay, Parnajyoti Karmakar, Debabrata Nandi, and Alak K. Ghosh
Springer Science and Business Media LLC
Arup Mandal, Parnajyoti Karmakar, Biplab K. Bera, Sumon Ray, Subala Mondal, and Alak K. Ghosh
SAGE Publications
The interaction of the cis-diaqua-chloro-tris(dimethyl sulfoxide)ruthenium(II) complex with selected nucleosides such as adenosine (L1H) and cytidine (L2H) has been studied spectrophotometrically in aqueous medium as a function of [substrate complex], [ligand] and temperature. The reaction has been monitored at 295 nm where the difference in spectra between the reactant and product is a maximum. At pH 5.0, the interaction with the two nucleosides shows two distinct consecutive steps, i.e., it shows a non-linear dependence on the concentration of the nucleosides: both steps are [ligand] dependent. The rate constants for the processes are: k1∼ 10–3s–1and k2∼ 10–5s–1. The activation parameters were calculated from Eyring plots. Based on the kinetic and activation parameters, an associative interchange mechanism is proposed for the interaction processes. From the temperature dependence of the outer sphere association equilibrium constant, the thermodynamic parameters were also calculated, which gives a negative Δ G° value for both the steps at all temperatures studied, supporting the spontaneous formation of an outer sphere association complex. The product of the reaction has been characterised by IR and ESI-mass spectroscopic analysis.
Parnajyoti Karmakar, Sumon Ray, Arup Mandal, Subala Mondal, Subhasis Mallick, Biplab K. Bera, and Alak K. Ghosh
Informa UK Limited
The kinetics of interaction of cis-[Pt(cis-dach)(H2O)2]2+ (where dach is cis-1,2-diaminocyclohexane) with three different amino acids, namely L-Asparagine (L1H), L-Arginine (L2H), and L-Gluatmic acid (L3H) have been studied spectrophotometrically in the 40–60°C temperature range. The substitution was found to occur in two subsequent reaction steps: the first step is the ligand-assisted anation and the second one is the chelation step. The kinetic study has been substantiated by product isolation, IR, NMR, and ESI-MS spectroscopic analysis.
Biplab K. Bera, Sumon Ray, Subala Mondal, Parnajyoti Karmakar, Arup Mandal, Subhasis Mallick, and Alak K. Ghosh
Hindawi Limited
The kinetics of the interaction of three glycine-containing dipeptides, namely, glycyl-L-alanine (L1-L′H), glycyl-L-asparagine (L2-L′H), and glycyl-L-tyrosine (L3-L′H) with has been studied spectrophotometrically in aqueous medium as a function of the molar concentration of , [dipeptide], pH, and temperature at constant ionic strength. Reactions were studied at pH 4.3, where the substrate complex exists predominantly as the hydroxopentaaqua species and dipeptides as the zwitterion. The reaction has been found to proceed via two parallel paths: both processes are ligand dependent. The rate constant for the processes are and . The activation parameters for both the steps were evaluated using Eyring’s equation. The low and large negative value of as well as and indicate an associative mode of activation for both the aqua ligand substitution processes for both the parallel paths. The product of the reaction has been characterized by IR and ESI-mass spectroscopic analyses.
Parnajyoti Karmakar, Sumon Ray, Debabrata Nandi, Arup Mandal, Subala Mondal, Subhasis Mallick, Biplab K. Bera, and Alak K. Ghosh
Springer Science and Business Media LLC
Arup Mandal, Subala Mondal, Parnajyoti Karmakar, Subhasis Mallick, Biplab K. Bera, and Alak K. Ghosh
Wiley
AbstractThe interaction of the title complex with selected amino acids such as glycine (L1H), l‐valine (L2H), and l‐leucine (L3H) has been studied spectrophotometrically in aqueous medium as a function of [substrate complex], [ligand], and temperature. The reaction has been monitored at 600 nm, where the spectral difference between the reactant and product is maximum. At pH 7.4, the reaction has been found to proceed via two distinct consecutive steps, i.e., it shows a nonlinear dependence on the concentration of ligands: The first process is [ligand] dependent, but the second step is [ligand] independent. The rate constants for the processes are k1∼10−3 s−1 and k2∼10−4 s −1. The activation parameters were calculated from Eyring plots. Based on the kinetic and activation parameters, an associative interchange mechanism is proposed for the interaction processes. From the temperature dependence of the outer sphere association equilibrium constant, the thermodynamic parameters were also calculated, which gives a negative Δ Go value for both the steps at all temperatures studied, supporting the spontaneous formation of an outer sphere association complex. The product of the reaction has been characterized with the help of conductance measurement, IR, NMR, and ESI‐mass spectroscopic analysis. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 612–623, 2012
BIPLAB K BERA, ARUP MANDAL, BISWARUP MAITY, SUMON RAY, PARNAJYOTI KARMAKAR, SUBALA MONDAL, SUBHASIS MALLICK, and ALAK K GHOSH
Springer Science and Business Media LLC
ARUP MANDAL, PARNAJYOTI KARMAKAR, SUBHASIS MALLICK, BIPLAB K BERA, SUBALA MONDAL, SUMON RAY, and ALAK K GHOSH
Springer Science and Business Media LLC
Subhasis Mallick, Arup Mandal, Biplab K. Bera, Pamajyoti Karmakar, Subala Mondal, and Alak K Ghosh
SAGE Publications
The interaction of diethyldithiocarbamate (Et2DTC) with diaquaethylenediamineplatinum(II) has been studied spectrophotometrically in aqueous medium as a function of [substrate complex], [ligand], temperature and pH at constant ionic strength. The reaction proceeds via rapid outer-sphere association complex formation followed by two consecutive steps: the first is ligand dependent and second is assigned to intramolecular ring closure. The low enthalpy and negative entropy of activation indicate an associative mode of activation for both steps.
Arup Mandal, Subhasis Mallick, Parnajyoti Karmakar, Biplab K. Bera, Subala Mondal, and Alak K. Ghosh
SAGE Publications
The interaction of glycyl-L-leucine (L-I/H) with [(H2O) (tap)2RuORu(tap)2(H2O)]2+ (tap=2-(m-tolylazo) pyridine) has been studied spectrophotometrically in aqueous medium as a function of [(H2O) (tap)2RuORu(tap)2(H2O)2+], [glycyl-L-leucine], pH and temperature. The reaction was monitored at 600 nm where the spectral difference between the reactant and product is a maximum. At pH 7.4, the interaction with glycyl-L-leucine shows two parallel steps, i.e. it shows a non-linear dependence on the concentration of glycyl-L-leucine; both processes are ligand dependent. The rate constants for the processes are: kl 10−3 s 1 and K2∼10−5 s−1. The activation parameters calculated from Eyring plots are: Δ H#1 = 15.8∓0.6kJ mol−1, A Sf = −232 + 2J K 1 mol−1, AH2# =31.7∓3.5kJmol−1, AS* = −216∓ 10J K−1 mol−1. Based on the kinetic and activation parameters, an associative interchange mechanism is proposed for the interaction processes. from the temperature dependence of the outer sphere association equilibrium constant, the thermodynamic parameters were also calculated, which gave a negative AG° value for both the steps at all temperatures studied, supporting the spontaneous formation of an outer sphere association complex. The product of the reaction has been characterized from IR and ESI-mass spectroscopic analysis.
ARUP MANDAL, SUBALA MONDAL, PARNAJYOTI KARMAKAR, BIPLAB K BERA, SUBHASIS MALLICK, and ALAK K GHOSH
Springer Science and Business Media LLC
Subhasis Mallick, Subala Mondal, Arup Mandal, Biplab K. Bera, Parnajyoti Karmakar, and Alak K. Ghosh
Wiley
AbstractThe kinetics of the interaction of three glycine‐containing dipeptides, namely, glycine‐L‐leucine (Gly‐Leu), glycine‐L‐isoleucine (Gly‐Ile), and glycine‐valine (Gly‐Val) with [Pt(en)(H2O)2](ClO4)2 has been studied spectrophotometrically as a function of [substrate complex], [dipeptides] and temperature at a particular pH(4.0), where the substrate complex exists predominantly as the diaqua species and the dipeptides as a zwitterion. The substitution reaction shows two consecutive steps; the first is the ligand‐assisted anation and the second is the chelation step. The activation parameters for both the steps were evaluated using Eyring's equation. The low ΔH1≠ and large negative value of ΔS1≠ as well as ΔH2≠ and ΔS2≠ indicate an associative mode of activation for both the aqua ligand substitution processes. © 2011 Wiley Periodicals, Inc. Int J Chem Kinet 43: 498–506, 2011
Parnajyoti Karmakar, Subhasis Mallick, Subala Mondal, Biplab K. Bera, Arup Mandal, Sudip K. Mukhopadhyay, and Alak K. Ghosh
Wiley
AbstractThe kinetics of the interaction of adenosine with cis‐[Pt(cis‐dach)(OH2)2]2+ (dach = diaminocyclohexane) was studied spectrophotometrically as a function of [cis‐[Pt(cis‐dach)(OH2)2]2+], [adenosine], and temperature at a particular pH (4.0), where the substrate complex exists predominantly as the diaqua species and the ligand adenosine exists as a neutral molecule. The substitution reaction shows two consecutive steps: the first is the ligand‐assisted anation followed by a chelation step. The activation parameters for both the steps have been evaluated using Eyring equation. The low negative value of ΔH≠1 (43.1 ± 1.3 kJ mol−1) and the large negative value of ΔS≠1 (−177 ± 4 J K−1 mol−1) along with ΔH≠2 (47.9 ± 1.8 kJ mol−1) and ΔS≠2 (−181 ± 6 J K−1 mol−1) indicate an associative mode of activation for both the aqua ligand substitution processes. The kinetic study was substantiated by infrared and electrospray ionization mass spectroscopic analysis. © 2011 Wiley Peiodicals, Inc. Int J Chem Kinet 43: 219–229, 2011
Subhasis Mallick, Biplab K. Bera, Parnajyoti Karmakar, Subala Mondal, Arup Mandal, and Alak K. Ghosh
Springer Science and Business Media LLC
Biplab K. Bera, Subhasis Mallick, Arup Mandal, Subala Mondal, Parnajyoti Karmakar, and Alak K. Ghosh
SAGE Publications
The kinetics of interaction between glycyl-glycine (L-L'H) and[Formula: see text] [Rh(H2O)5OH] 2+ have been studied spectrophotometrically in aqueous medium as a function of [Rh(H2O)5OH] 2+], [glycyl - glycine], pH and temperature at constant ionic strength. At pH 4.3, the interaction with glycyl-glycine shows two parallel paths: both processes are ligand-dependent. The rate constant for the processes are: k1 ∼ 10 −3 s −1 and k2∼10−5 s−3. The activation parameters calculated from Eyring plots are: ΔH1≠ - 26.7 ± 0.3 kj mol−1, ΔS1≠ =-207+1 JK−1 mol−1, ΔH2≠ = 92.4 ± 1.3 kJ mol−1 and ΔS2≠ = −42±4 JK−1 mol−1. The ligand glycyl-glycine, with different donor atoms (N and O), attacks two rhodium(III) ions (Rh(III) being a borderline acid), with different reactivity. Based on the kinetic and activation parameters, an associative interchange mechanism is proposed for both interaction processes. From the temperature dependence of the outer-sphere association equilibrium constant, the thermodynamic parameters calculated are: ΔH1∘ = 21.8 ± 1.9 kJ mol−1, ΔS1∘ = 124± 6 JK−1 mol−1, ΔH2∘ = 12.7 ±0.5 kj mol−1 and ΔS2∘ 89±2 JK−1 mol″−1 which give a negative A G° value for both the steps at all temperatures studied, supporting the spontaneous formation of an outer- sphere association complex for both the parallel paths. The product of the reaction has been characterized from IR and ESI-mass spectroscopic analysis.
SUBHASIS MALLICK, BIPLAB K BERA, SUBALA MONDAL, PARNAJYOTI KARMAKAR, ARUP MANDAL, and ALAK K GHOSH
Springer Science and Business Media LLC
Parnajyoti Karmakar, Subhasis Mallick, Biplab K. Bera, Arup Mandal, Subala Mondal, Sudip K. Mukhopadhyay, and Alak K. Ghosh
Springer Science and Business Media LLC
Tandra Das(Karfa), Biplab K. Bera, Subhasis Mallick, Parnajyoti Karmakar, Arup Mandal, Subala Mondal, Gauri S. De, and Alak K. Ghosh
Springer Science and Business Media LLC
Biplab K. Bera, Subhasis Mallick, Arup Mandal, Parnajyoti Karmakar, Asok K. Datta, and Alak K. Ghosh
Springer Science and Business Media LLC