Susil Kar College

Bāruipur, India

Susil Kar College

Bāruipur, India
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Naiya S.,University of Calcutta | Naiya S.,Susil Kar College | Wang H.-S.,Nanjing University | Drew M.G.B.,University of Reading | And 2 more authors.
Dalton Transactions | Year: 2011

Four new nickel(ii) complexes, [Ni2L2(NO 2)2]·CH2Cl2·C 2H5OH, 2H2O (1), [Ni2L 2(DMF)2(μ-NO2)]ClO4·DMF (2a), [Ni2L2(DMF)2(μ-NO2)] ClO4 (2b) and [Ni3L'2(μ3-NO 2)2(CH2Cl2)]n·1. 5H2O (3) where HL = 2-[(3-amino-propylimino)-methyl]-phenol, H 2L' = 2-({3-[(2-hydroxy-benzylidene)-amino]-propylimino}- methyl)-phenol and DMF = N,N-dimethylformamide, have been synthesized starting with the precursor complex [NiL2]·2H2O, nickel(ii) perchlorate and sodium nitrite and characterized structurally and magnetically. The structural analyses reveal that in all the complexes, NiII ions possess a distorted octahedral geometry. Complex 1 is a dinuclear di-μ2-phenoxo bridged species in which nitrite ion acts as chelating co-ligand. Complexes 2a and 2b also consist of dinuclear entities, but in these two compounds a cis-(μ-nitrito-1κO:2κN) bridge is present in addition to the di-μ2-phenoxo bridge. The molecular structures of 2a and 2b are equivalent; they differ only in that 2a contains an additional solvated DMF molecule. Complex 3 is formed by ligand rearrangement and is a one-dimensional polymer in which double phenoxo as well as μ-nitrito-1κO:2κN bridged trinuclear units are linked through a very rare μ3-nitrito-1κO:2κN:3κO′ bridge. Analysis of variable-temperature magnetic susceptibility data indicates that there is a global weak antiferromagnetic interaction between the nickel(ii) ions in four complexes, with exchange parameters J of -5.26, -11.45, -10.66 and -5.99 cm-1 for 1, 2a, 2b and 3, respectively. © The Royal Society of Chemistry 2011.


Naiya S.,University of Calcutta | Naiya S.,Susil Kar College | Drew M.G.B.,University of Reading | Diaz C.,University of Barcelona | And 2 more authors.
European Journal of Inorganic Chemistry | Year: 2011

Two new Fe III complexes, [Fe 2L 2(μ-OMe) 2(NCS) 2] (1) and [Fe 2L 2(μ-N 3) 2(N 3) 2] (2), have been synthesized using a N,N,O-donor tridentate Schiff base ligand HL {2-[(2- dimethylaminoethylimino)methyl]phenol}, the condensation product of salicylaldehyde and N,N-dimethyl-1,2-diaminoethane. The complexes were characterized by X-ray structural analyses and variable-temperature magnetic susceptibility measurements. Both crystal structures are centrosymmetric dimers containing two Fe III atoms, which are bridged in compound 1 by two methoxy anions and in compound 2 by two μ-1,1-azides. The chelating tridentate Schiff base and a terminal thiocyanato (for 1) or azido (for 2) group complete the hexacoordination of the distorted octahedral environment of each iron center. The magnetic properties of compound 1 show the presence of antiferromagnetic exchange interactions mediated by double methoxy bridges (J =-29.45 cm -1). Compound 2 shows the presence of very weak ferromagnetic exchange interactions mediated by double μ-1,1-N 3 bridges (J = 1.08 cm -1). A very rare μ-1,1-azido-bridged and a μ-OMe-bridged dinuclear Fe III compound with a tridentate N,N,O-donor Schiff base have been synthesized and characterized structurally. The former is only the third example of μ-1,1-azido bridges in Fe III. The variable-temperature magnetic studies show that the former is ferromagnetically and the latter antiferromagneticallycoupled. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.


Biswas S.,University of Calcutta | Naiya S.,University of Calcutta | Naiya S.,Susil Kar College | Gomez-Garcia C.J.,University of Valencia | Ghosh A.,University of Calcutta
Dalton Transactions | Year: 2012

A tetra-nuclear, star-shaped hetero-metallic copper(ii)-manganese(ii) complex, [{CuL(H 2O)} 2(CuL)Mn](ClO 4) 2 (1) has been synthesized by reacting the "complex as ligand" [CuL] with Mn(ClO 4) 2 where H 2L is the tetradentate di-Schiff base derived from 1,3-propanediamine and 2-hydroxyacetophenone. Upon treatment with the polyatomic anions azide, cyanate, or thiocyanate in methanol medium, complex 1 transforms into the corresponding trinuclear species [(CuL) 2Mn(N 3) 2] (2), [(CuL) 2Mn(NCO) 2] (3) and [(CuL) 2Mn(NCS) 2] (4). All four complexes have been structurally and magnetically characterized. In complex 1 the central Mn(ii) ion is encapsulated by three terminal [CuL] units through the formation of double phenoxido bridges between Mn(ii) and each Cu(ii). In complexes 2-4 one of the CuL units is replaced by a couple of terminal azide, N-bonded cyanate or N-bonded thiocyanate ions respectively and the central Mn(ii) ion is connected to two terminal Cu(ii) ions through a double asymmetric phenoxido bridge. Variable temperature magnetic susceptibility measurements show the presence of moderate ferrimagnetic exchange interactions in all the cases mediated through the double phenoxido bridges with J values (H = -JS iS i + 1) of -41.2, -39.8 and -12.6 cm -1 (or -40.5 and -12.7 cm -1 if we use a model with two different exchange coupling constants) for the tetranuclear MnCu 3 cluster in compound 1 and -20.0, -17.3 and -32.5 cm -1 for the symmetric trinuclear MnCu 2 compounds 2-4. These ferrimagnetic interactions lead to spin ground states of 1 (5/2 - 3*1/2) for compound 1 and 3/2 (5/2 - 2*1/2) for compounds 2-4. © 2012 The Royal Society of Chemistry.


Biswas S.,University of Calcutta | Naiya S.,University of Calcutta | Naiya S.,Susil Kar College | Drew M.G.B.,University of Reading | Ghosh A.,University of Calcutta
Journal of the Indian Chemical Society | Year: 2012

The synthesis of a new sodium perchlorate adduct (1:3) with a copper(II) "ligand-complex" is reported in which 2-hydroxyacetophenone acts as a guest. The adduct is tetranuclear of formula {[(CuL)3Na]ClO 4}2·C8O2H8· 0.5CH3CN (1). The ligand is the tetradentate di-Schiff base of 1,3-propanediamines and o-hydroxyacetophenone (H2L). The complex has been characterized by X-ray single crystal structure analysis. In the structure, the sodium cation has a six-coordinate distorted octahedral environment being bonded to six oxygen atoms from three Schiff base complexes. The complex exhibits reversible reductive (CuII/CuI; Epc, -0.914 V) and oxidative (CuII/CuIII; Epa, +1.060 V respectively) responses in cyclic voltammetry. The generated Cu I species for the complex is unstable and undergoes disproportionation to Cu0 and Cu2+.


Naiya S.,University of Calcutta | Naiya S.,Susil Kar College | Biswas S.,University of Calcutta | Drew M.G.B.,University of Reading | And 2 more authors.
Inorganica Chimica Acta | Year: 2011

Three Cu(II)-azido complexes of formula [Cu2L2(N 3)2] (1), [Cu2L2(N3) 2]·H2O (2) and [CuL(N3)]n (3) have been synthesized using the same tridentate Schiff base ligand HL (2-[(3-methylaminopropylimino)-methyl]-phenol), the condensation product of N-methyl-1,3-propanediamine and salicyldehyde). Compounds 1 and 2 are basal-apical μ-1,1 double azido bridged dimers. The dimeric structure of 1 is centrosymmetric but that of 2 is non-centrommetric. Compound 3 is a μ-1,1 single azido bridged 1D chain. The three complexes interconvert in solution and can be obtained in pure form by carefully controlling the synthetic conditions. Compound 2 undergoes an irreversible transformation to 1 upon dehydration in the solid state. The magnetic properties of compounds 1 and 2 show the presence of weak antiferromagnetic exchange interactions mediated by the double 1,1-N 3 azido bridges (J = -2.59(4) and -0.10(1) cm-1, respectively). The single 1,1-N3 bridge in compound 3 mediates a negligible exchange interaction. © 2011 Elsevier B.V. All rights reserved.


Biswas S.,University of Calcutta | Naiya S.,University of Calcutta | Naiya S.,Susil Kar College | Drew M.G.B.,University of Reading | And 3 more authors.
Inorganica Chimica Acta | Year: 2011

The synthesis of two new sodium perchlorate adducts (1:2 and 1:3) with copper(II) "ligand-complexes" is reported. One adduct is trinuclear [(CuL 1) 2NaClO 4] (1) and the other is tetranuclear [(CuL 2) 3Na]ClO 4·EtOH (2). The ligands are the tetradentate di-Schiff base of 1,3-propanediamines and salicylaldehyde (H 2L 1) or 2-hydroxyacetophenone (H 2L 2). Both complexes have been characterized by X-ray single crystal structure analyses. In both structures, the sodium cation has a six-coordinate distorted octahedral environment being bonded to four oxygen atoms from two Schiff-base complexes in addition to a chelated perchlorate anion in 1 and to six oxygen atoms from three Schiff-base complexes in 2. We have carried out a DFT theoretical study (RI-B97-D/def2-SVP level of theory) to compute and compare the formation energies of 1:2 and 1:3 adducts. The DFT study reveals that the latter is more stabilized than the former. The X-ray crystal structure of 1 shows that the packing of the trinuclear unit is controlled by unconventional C-H···O H-bonds and Cu 2+-π non-covalent interactions. These interactions explain the formation of 1 which is a priori disfavored with respect to 2. © 2010 Elsevier B.V. All rights reserved.


Naiya S.,University of Calcutta | Naiya S.,Susil Kar College | Biswas S.,University of Calcutta | Drew M.G.B.,University of Reading | Ghosh A.,University of Calcutta
Inorganic Chemistry Communications | Year: 2012

An alternating hexameric water (H 2O) 6 cluster and a chlorine-water cluster [Cl 2(H 2O) 4] 2- in the chair forms combine axially to each other to form a 1D chain [{Cl 2(H 2O) 6} 2-] n in complex [FeL 2]Cl·(H 2O) 3 (L = 2-[(2-methylaminoethylimino)-methyl]-phenol)]. The water molecules display extensive H-bonding interactions with monomeric iron-organic units to form a hydrogen-bonded 2D supramolecular assembly. © 2012 Elsevier B.V. All rights reserved.


Naiya S.,University of Calcutta | Naiya S.,Susil Kar College | Biswas S.,University of Calcutta | Drew M.G.B.,University of Reading | Ghosh A.,University of Calcutta
Polyhedron | Year: 2012

Two new nickel(II) complexes, [NiL(H 2O) 2Cl] (1) and [{NiLL′(H 2O)} 2(μ-H)]NO 3·H 2O (2), have been synthesized using a tridentate Schiff base ligand, HL, 2-[(2-dimethylamino-ethylimino)-methyl]-phenol, along with Cl - or NO 3 - as an anionic co-ligand or counter anion (where L′H = salicylaldehyde). Both complexes have been characterized by X-ray crystallography. The structural analyses reveal that complex 1 is mononuclear whereas 2 is a hydrogen-bridged dinuclear complex. The Ni(II) ions possess a distorted octahedral geometry in both structures. Both complexes show negative solvatochromic behaviour with increasing donor number (DN) of the solvent. In more coordinating solvents, like DMSO or methanol, the colour of the solutions is green, whereas in less coordinating solvents, like dichloromethane (DCM) or acetonitrile, it is red. © 2011 Elsevier Ltd. All rights reserved.


Naiya S.,University of Calcutta | Naiya S.,Susil Kar College | Biswas S.,University of Calcutta | Drew M.G.B.,University of Reading | And 2 more authors.
Inorganic Chemistry | Year: 2012

Two new Mn(III) complexes of formulas [MnL 1(N 3)(OMe)] 2 (1) and [MnL 2(N 3) 2] n (2) have been synthesized by using two tridentate NNO-donor Schiff base ligands HL 1{(2-[(3-methylaminoethylimino)- methyl]-phenol)} and HL 2 {(2-[1-(2-dimethylaminoethylimino)methyl] phenol)}, respectively. Substitution of the H atom on the secondary amine group of the N-methyldiamine fragment of the Schiff base by a methyl group leads to a drastic structural change from a methoxido-bridged dimer (1) to a single μ 1,3-azido-bridged 1D helical polymer (2). Both complexes were characterized by single-crystal X-ray structural analyses and variable-temperature magnetic susceptibility measurements. The magnetic properties of compound 1 show the presence of weak ferromagnetic exchange interactions mediated by double methoxido bridges (J = 0.95 cm -1). Compound 2 shows the existence of a weak antiferromangetic coupling along the chain (J = -8.5 cm -1) through the single μ 1,3-N 3 bridge with a spin canting that leads to a long-range antiferromagnetic order at T c ≈ 9.3 K and a canting leading to a weak ferromagnetic long-range order at T c ≈ 8.5 K. It also exibits metamagnetic behavior at low temperatures with a critical field of ca.1.2 T due to the weak antiferromagnetic interchain interactions that appear in the canted ordered phase. © 2012 American Chemical Society.


Hazra S.,University of Calcutta | Hazra S.,Bankura Sammilani College | Sarkar B.,University of Calcutta | Sarkar B.,Bolpur College | And 6 more authors.
Inorganic Chemistry Communications | Year: 2011

Structural characterization of a new self assembled coordination polymer of Cu II, hexamine (hmt) and benzoate (OBz), [Cu 4(OBz) 8(hmt)] n (1), reveals that it is a cubic non-interpenetrating diamondoid network formed by the coordination of the μ 4-hmt ligand to a linear [Cu 2(OBz) 4] spacer. The magnetic study reveals that the Cu(II) ions are antiferromagnetically coupled (J = - 323.5 cm -1) through the syn-syn carboxylate bridges. © 2011 Elsevier B.V. All rights reserved.

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