Shyamal Chattopadhyay - Academia.edu (original) (raw)
Papers by Shyamal Chattopadhyay
Structural Chemistry, Feb 7, 2007
ABSTRACT Anthraniloyl hydrazide (AH) contains two −NH2 groups, one of them is attached to the aro... more ABSTRACT Anthraniloyl hydrazide (AH) contains two −NH2 groups, one of them is attached to the aromatic ring and the other is the hydrazinic, −NH2. It is found that only the later reacts with the carbonyl compounds to form Schiff bases, while the former remains inert. The reasons behind this difference in reactivity are analyzed on the basis of semi-empirical calculations, which show that the lone pair of the ring −NH2 is considerably delocalized over the ring, resulting in an accumulation of a positive charge on this particular nitrogen. Ni(II) complex of 2,6-diacetylpyridine bis(anthraniloyl hydrazone) has been prepared and characterized by various physico-chemical methods. The structure of the complex was determined by X-ray crystallography. It was found that in the solid state, the compound exist as a dimer, and two coordinated ligand moieties form a double helix around the two metal ions. H-bonding then results in extension of double helix to an infinite chain.
Polyhedron, 2010
Two mononuclear zinc(II) complexes, [ZnL1H2Cl]Cl·2H2O (1·Cl·2H2O) and [ZnL2HCl]·H2O (2·H2O) (L1H2... more Two mononuclear zinc(II) complexes, [ZnL1H2Cl]Cl·2H2O (1·Cl·2H2O) and [ZnL2HCl]·H2O (2·H2O) (L1H2 and L2H2 are N,N′-bis(pyridoxylidene)ethylenediamine and N,N′-bis(pyridoxylidene)1,3-propanediamine, respectively) have been synthesized and characterized by elemental analysis, FT-IR, fluorescence spectroscopy, TG–DTA and single crystal X-ray diffraction studies. The Zn(II) ion in complex 1 have a square pyramidal geometry with appreciable distortion towards trigonal bipyramid, whereas in 2 it has a geometry which
Inorganica Chimica Acta, 2010
Two Ni(II) complexes of the ligands N,N′-dipyridoxylethylenediimine (L 1 H 2 ) and N,N′-dipyridox... more Two Ni(II) complexes of the ligands N,N′-dipyridoxylethylenediimine (L 1 H 2 ) and N,N′-dipyridoxyl-1,3-propanediimine (L 2 H 2 ) were synthesized and their structures were determined by X-ray crystallography. The complexes are of formula Ni(L 1 ). 3H 2 O (1·3H ...
European Journal of Inorganic Chemistry, May 14, 2013
International Journal of Chemical Kinetics
Journal of the Indian Chemical Society, 2022
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2022
Fluorogenic chemosensors using pyridoxal derivatized ligands as fluorophore is a rapidly growing ... more Fluorogenic chemosensors using pyridoxal derivatized ligands as fluorophore is a rapidly growing field of research. Here we report a new Fe(III) complex, [Fe(HBala-pydx)(Bala-pydx)] (H2Bala-pydx is the Schiff base of pyridoxal with beta-alanine), which can serve as a sensitive and selective turn-on fluorescent sensor for the detection of cyanide(CN-) in micromolar concentrations (L.O.D. is 1.134 µM), via the ligand displacement approach, in aqueous-acetonitrile medium. The Fe(III) complex is adequately characterized by analytical and spectroscopic methods along with X-ray crystal structure determination.
Related Article: Shipra Sagar, Swaraj Sengupta, Antonio J. Mota, Shyamal K. Chattopadhyay, Arturo... more Related Article: Shipra Sagar, Swaraj Sengupta, Antonio J. Mota, Shyamal K. Chattopadhyay, Arturo Espinosa Ferao, Eric Riviere, William Lewis, Subhendu Naskar|2017|Dalton Trans.|46|1249|doi:10.1039/C6DT03754B
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
New Journal of Chemistry, 2020
Three Cu(ii) complexes showing efficient catecholase activity, with pronounced solvent sensitivit... more Three Cu(ii) complexes showing efficient catecholase activity, with pronounced solvent sensitivity, S2−sensing ability in micromolar concentrations, and coligand dependent denticity of the pyridoxal Schiff base ligand are reported.
New Journal of Chemistry, 2020
A binuclear Cu(ii) complex of aminoguanidine shows strong DNA binding activity and encouraging an... more A binuclear Cu(ii) complex of aminoguanidine shows strong DNA binding activity and encouraging anti-cancer activity against HCT-16 cells. The complex can also be used for selective spectrophotomteric or fluorometric determination of histidine.
New Journal of Chemistry, 2020
A Mn(ii) complex containing two tridentate O,N,O-donor semicarbazone ligands shows very high cata... more A Mn(ii) complex containing two tridentate O,N,O-donor semicarbazone ligands shows very high catalytic activity for the aerial oxidation of 3,5DTBCH2withkcat= 3.10 × 106h−1, andkcat/KM= 3.25 × 108h−1M−1.
New J. Chem., 2014
Au(i)–NHC (3) is more potent than Au(iii)–NHC (4) and cisplatin against the four cancer cell lines.
Inorganica Chimica Acta, 2010
Five Ni(II) complexes of aroyl hydrazone ligands with 2,6-diacetyl pyridine monooxime are reporte... more Five Ni(II) complexes of aroyl hydrazone ligands with 2,6-diacetyl pyridine monooxime are reported. X-ray crystal structure of the Ni(II) salicyloylhydrazone complex is also reported. In these complexes Ni(II) is in a distorted octahedral N 4 O 2 coordination environment, with each ...
Journal of Coordination Chemistry, 2018
Two new complexes, [MnL 2 ](ClO 4) (1) and [CuL 2 ] (2) (where LH = (E)-1-((3-(dimethylamino)prop... more Two new complexes, [MnL 2 ](ClO 4) (1) and [CuL 2 ] (2) (where LH = (E)-1-((3-(dimethylamino)propylimino)methyl)naphthalen-2-ol), have been synthesized and characterized by spectroscopic techniques and their molecular structures are established by single-crystal X-ray diffraction study. Complex 1 adopts an octahedral geometry around the central manganese atom which is in +3 oxidation state, whereas in complex 2, the Cu +2 ion preferred a square pyramidal environment around it through the ligand donor atoms. Both complexes were tested for catecholase and phenoxazinone synthase activity. Complex 1 catalyzes the oxidation of 3,5ditertiary-butyl catechol with a k cat value of 6.8424×10 2 h-1 in acetonitrile whereas the same for complex 2 is 3.7485×10 2 h-1 in methanol. Phenoxazinone synthase activity was shown only by complex 2 having k cat = 74.225 h-1. Structures of both the title complexes have been optimized by means of DFT calculations. Experimental electronic spectra of the complexes have been corroborated by TDDFT analysis. Electrochemical investigations by means of cyclic voltammetry have been carried out to study the electron transfer processes in the complexes.
Polyhedron, Nov 1, 2015
Abstract Four new Ruthenium(II) complexes [Ru(bbp)(pyterpy)](PF6)2 (1), [Ru(bbp)(bip)Cl]PF6 (2), ... more Abstract Four new Ruthenium(II) complexes [Ru(bbp)(pyterpy)](PF6)2 (1), [Ru(bbp)(bip)Cl]PF6 (2), [Ru(bbp)(biq)Cl]PF6 (3) and [Ru(bbp)(phen)Cl]PF6 (4) have been synthesized and characterized by spectroscopic techniques (IR, NMR and mass) and single crystal X-ray diffraction study of one of them (4) (where bbp = 2,6-bis(benzimidazolyl)pyridine, pyterpy = 4(4-pyridyl)terpyridine, phen = 1,10-phenanthroline, bip = 2-(benzimidazolyl)pyridine, biq = 2,2′-biquinoline). The electronic spectra of all the complexes show significant bathochromic shift of their lowest energy Metal to Ligand Charge Transfer band position with respect to [Ru(bpy)3]2+. The position of the MLCT band is modulated by the nature of the coligand, the 2,6-bis(benzimidazolyl)pyridine ligand being present in all the complexes. The change in the RuIII/II potential is also explained on the basis of the σ/π donor characteristic of the ligands.
Polyhedron, Feb 1, 2011
Two mononuclear Cu(II) complexes, [Cu(L 1 H 2)](ClO 4) 1.25 Cl 0.75 Á1.25H 2 O (1) and [Cu(L 2 H ... more Two mononuclear Cu(II) complexes, [Cu(L 1 H 2)](ClO 4) 1.25 Cl 0.75 Á1.25H 2 O (1) and [Cu(L 2 H 2)](ClO 4) 2 (2), of the pyridoxal Schiff base ligands N,N 0-dipyridoxylethylenediimine (L 1 H 2) and N,N 0-dipyridoxyl-1,3-propanediimine (L 2 H 2) are reported. X-ray crystal structures of both complexes are also reported. In both complexes the pyridoxal nitrogen atoms remain protonated. In the solid state, the tetradentate Schiff base ligand is virtually planar in 1, while in 2 the ligand conformation is like an inverted umbrella. In cyclic voltammetry experiments it is found that in these complexes the Cu(III) and Cu(I) states are more easily accessible than in their salen type analogs. The pyridoxal Schiff base complexes are also found to be resistant to oxidative electro-polymerization, unlike their corresponding salicyl aldehyde Schiff base complexes.
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](Polyhedron, May 1, 1998
The tBu PONOP (2,6-bis(di-tert-butyl-phosphinito)pyridine) complexes of iron and cobalt, (tBu PON... more The tBu PONOP (2,6-bis(di-tert-butyl-phosphinito)pyridine) complexes of iron and cobalt, (tBu PONOP)FeCl 2 (1) and (tBu PONOP)CoCl 2 (2)) have been prepared. Both complexes are paramagnetic and the solid-state structures of 1 and 2 were determined by single crystal X-ray diffraction studies. Analogous Fe and Co complexes of the tBu PNP (2,6-bis(di-tert-butyl-phosphinomethyl)pyridine) ligand (3 and 4, respectively) were prepared to allow comparison between the closely related pincer ligands in the hydrosilylation of carbonyl moieties. All four complexes were found to be catalytically active when treated with NaBEt 3 H, which was assumed to generate a metal-hydride species in-situ.
Structural Chemistry, Feb 7, 2007
ABSTRACT Anthraniloyl hydrazide (AH) contains two −NH2 groups, one of them is attached to the aro... more ABSTRACT Anthraniloyl hydrazide (AH) contains two −NH2 groups, one of them is attached to the aromatic ring and the other is the hydrazinic, −NH2. It is found that only the later reacts with the carbonyl compounds to form Schiff bases, while the former remains inert. The reasons behind this difference in reactivity are analyzed on the basis of semi-empirical calculations, which show that the lone pair of the ring −NH2 is considerably delocalized over the ring, resulting in an accumulation of a positive charge on this particular nitrogen. Ni(II) complex of 2,6-diacetylpyridine bis(anthraniloyl hydrazone) has been prepared and characterized by various physico-chemical methods. The structure of the complex was determined by X-ray crystallography. It was found that in the solid state, the compound exist as a dimer, and two coordinated ligand moieties form a double helix around the two metal ions. H-bonding then results in extension of double helix to an infinite chain.
Polyhedron, 2010
Two mononuclear zinc(II) complexes, [ZnL1H2Cl]Cl·2H2O (1·Cl·2H2O) and [ZnL2HCl]·H2O (2·H2O) (L1H2... more Two mononuclear zinc(II) complexes, [ZnL1H2Cl]Cl·2H2O (1·Cl·2H2O) and [ZnL2HCl]·H2O (2·H2O) (L1H2 and L2H2 are N,N′-bis(pyridoxylidene)ethylenediamine and N,N′-bis(pyridoxylidene)1,3-propanediamine, respectively) have been synthesized and characterized by elemental analysis, FT-IR, fluorescence spectroscopy, TG–DTA and single crystal X-ray diffraction studies. The Zn(II) ion in complex 1 have a square pyramidal geometry with appreciable distortion towards trigonal bipyramid, whereas in 2 it has a geometry which
Inorganica Chimica Acta, 2010
Two Ni(II) complexes of the ligands N,N′-dipyridoxylethylenediimine (L 1 H 2 ) and N,N′-dipyridox... more Two Ni(II) complexes of the ligands N,N′-dipyridoxylethylenediimine (L 1 H 2 ) and N,N′-dipyridoxyl-1,3-propanediimine (L 2 H 2 ) were synthesized and their structures were determined by X-ray crystallography. The complexes are of formula Ni(L 1 ). 3H 2 O (1·3H ...
European Journal of Inorganic Chemistry, May 14, 2013
International Journal of Chemical Kinetics
Journal of the Indian Chemical Society, 2022
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2022
Fluorogenic chemosensors using pyridoxal derivatized ligands as fluorophore is a rapidly growing ... more Fluorogenic chemosensors using pyridoxal derivatized ligands as fluorophore is a rapidly growing field of research. Here we report a new Fe(III) complex, [Fe(HBala-pydx)(Bala-pydx)] (H2Bala-pydx is the Schiff base of pyridoxal with beta-alanine), which can serve as a sensitive and selective turn-on fluorescent sensor for the detection of cyanide(CN-) in micromolar concentrations (L.O.D. is 1.134 µM), via the ligand displacement approach, in aqueous-acetonitrile medium. The Fe(III) complex is adequately characterized by analytical and spectroscopic methods along with X-ray crystal structure determination.
Related Article: Shipra Sagar, Swaraj Sengupta, Antonio J. Mota, Shyamal K. Chattopadhyay, Arturo... more Related Article: Shipra Sagar, Swaraj Sengupta, Antonio J. Mota, Shyamal K. Chattopadhyay, Arturo Espinosa Ferao, Eric Riviere, William Lewis, Subhendu Naskar|2017|Dalton Trans.|46|1249|doi:10.1039/C6DT03754B
An entry from the Cambridge Structural Database, the world's repository for small molecule cr... more An entry from the Cambridge Structural Database, the world's repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
New Journal of Chemistry, 2020
Three Cu(ii) complexes showing efficient catecholase activity, with pronounced solvent sensitivit... more Three Cu(ii) complexes showing efficient catecholase activity, with pronounced solvent sensitivity, S2−sensing ability in micromolar concentrations, and coligand dependent denticity of the pyridoxal Schiff base ligand are reported.
New Journal of Chemistry, 2020
A binuclear Cu(ii) complex of aminoguanidine shows strong DNA binding activity and encouraging an... more A binuclear Cu(ii) complex of aminoguanidine shows strong DNA binding activity and encouraging anti-cancer activity against HCT-16 cells. The complex can also be used for selective spectrophotomteric or fluorometric determination of histidine.
New Journal of Chemistry, 2020
A Mn(ii) complex containing two tridentate O,N,O-donor semicarbazone ligands shows very high cata... more A Mn(ii) complex containing two tridentate O,N,O-donor semicarbazone ligands shows very high catalytic activity for the aerial oxidation of 3,5DTBCH2withkcat= 3.10 × 106h−1, andkcat/KM= 3.25 × 108h−1M−1.
New J. Chem., 2014
Au(i)–NHC (3) is more potent than Au(iii)–NHC (4) and cisplatin against the four cancer cell lines.
Inorganica Chimica Acta, 2010
Five Ni(II) complexes of aroyl hydrazone ligands with 2,6-diacetyl pyridine monooxime are reporte... more Five Ni(II) complexes of aroyl hydrazone ligands with 2,6-diacetyl pyridine monooxime are reported. X-ray crystal structure of the Ni(II) salicyloylhydrazone complex is also reported. In these complexes Ni(II) is in a distorted octahedral N 4 O 2 coordination environment, with each ...
Journal of Coordination Chemistry, 2018
Two new complexes, [MnL 2 ](ClO 4) (1) and [CuL 2 ] (2) (where LH = (E)-1-((3-(dimethylamino)prop... more Two new complexes, [MnL 2 ](ClO 4) (1) and [CuL 2 ] (2) (where LH = (E)-1-((3-(dimethylamino)propylimino)methyl)naphthalen-2-ol), have been synthesized and characterized by spectroscopic techniques and their molecular structures are established by single-crystal X-ray diffraction study. Complex 1 adopts an octahedral geometry around the central manganese atom which is in +3 oxidation state, whereas in complex 2, the Cu +2 ion preferred a square pyramidal environment around it through the ligand donor atoms. Both complexes were tested for catecholase and phenoxazinone synthase activity. Complex 1 catalyzes the oxidation of 3,5ditertiary-butyl catechol with a k cat value of 6.8424×10 2 h-1 in acetonitrile whereas the same for complex 2 is 3.7485×10 2 h-1 in methanol. Phenoxazinone synthase activity was shown only by complex 2 having k cat = 74.225 h-1. Structures of both the title complexes have been optimized by means of DFT calculations. Experimental electronic spectra of the complexes have been corroborated by TDDFT analysis. Electrochemical investigations by means of cyclic voltammetry have been carried out to study the electron transfer processes in the complexes.
Polyhedron, Nov 1, 2015
Abstract Four new Ruthenium(II) complexes [Ru(bbp)(pyterpy)](PF6)2 (1), [Ru(bbp)(bip)Cl]PF6 (2), ... more Abstract Four new Ruthenium(II) complexes [Ru(bbp)(pyterpy)](PF6)2 (1), [Ru(bbp)(bip)Cl]PF6 (2), [Ru(bbp)(biq)Cl]PF6 (3) and [Ru(bbp)(phen)Cl]PF6 (4) have been synthesized and characterized by spectroscopic techniques (IR, NMR and mass) and single crystal X-ray diffraction study of one of them (4) (where bbp = 2,6-bis(benzimidazolyl)pyridine, pyterpy = 4(4-pyridyl)terpyridine, phen = 1,10-phenanthroline, bip = 2-(benzimidazolyl)pyridine, biq = 2,2′-biquinoline). The electronic spectra of all the complexes show significant bathochromic shift of their lowest energy Metal to Ligand Charge Transfer band position with respect to [Ru(bpy)3]2+. The position of the MLCT band is modulated by the nature of the coligand, the 2,6-bis(benzimidazolyl)pyridine ligand being present in all the complexes. The change in the RuIII/II potential is also explained on the basis of the σ/π donor characteristic of the ligands.
Polyhedron, Feb 1, 2011
Two mononuclear Cu(II) complexes, [Cu(L 1 H 2)](ClO 4) 1.25 Cl 0.75 Á1.25H 2 O (1) and [Cu(L 2 H ... more Two mononuclear Cu(II) complexes, [Cu(L 1 H 2)](ClO 4) 1.25 Cl 0.75 Á1.25H 2 O (1) and [Cu(L 2 H 2)](ClO 4) 2 (2), of the pyridoxal Schiff base ligands N,N 0-dipyridoxylethylenediimine (L 1 H 2) and N,N 0-dipyridoxyl-1,3-propanediimine (L 2 H 2) are reported. X-ray crystal structures of both complexes are also reported. In both complexes the pyridoxal nitrogen atoms remain protonated. In the solid state, the tetradentate Schiff base ligand is virtually planar in 1, while in 2 the ligand conformation is like an inverted umbrella. In cyclic voltammetry experiments it is found that in these complexes the Cu(III) and Cu(I) states are more easily accessible than in their salen type analogs. The pyridoxal Schiff base complexes are also found to be resistant to oxidative electro-polymerization, unlike their corresponding salicyl aldehyde Schiff base complexes.
Polyhedron, May 1, 1998
The tBu PONOP (2,6-bis(di-tert-butyl-phosphinito)pyridine) complexes of iron and cobalt, (tBu PON... more The tBu PONOP (2,6-bis(di-tert-butyl-phosphinito)pyridine) complexes of iron and cobalt, (tBu PONOP)FeCl 2 (1) and (tBu PONOP)CoCl 2 (2)) have been prepared. Both complexes are paramagnetic and the solid-state structures of 1 and 2 were determined by single crystal X-ray diffraction studies. Analogous Fe and Co complexes of the tBu PNP (2,6-bis(di-tert-butyl-phosphinomethyl)pyridine) ligand (3 and 4, respectively) were prepared to allow comparison between the closely related pincer ligands in the hydrosilylation of carbonyl moieties. All four complexes were found to be catalytically active when treated with NaBEt 3 H, which was assumed to generate a metal-hydride species in-situ.