Arunendu Mondal
Indian Association for the Cultivation of Science
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Featured researches published by Arunendu Mondal.
Polyhedron | 2000
Inamur Rahaman Laskar; Ashutosh Ghosh; Golam Mostafa; Debasis Das; Arunendu Mondal; Nirmalendu Ray Chaudhuri
Abstract The complexes [NiL3](NO2)2·2H2O (violet, 1) and cis-[NiL2(NO2)2]·0.5H2O (pink, 1b) (L=1,2-diamino-2-methylpropane) have been synthesized from solution. The X-ray single crystal structure analysis of compound 1b has been carried out, but the presence of a water molecule cannot be detected. Upon heating, complex 1b undergoes dehydration followed by an endothermic phase transition to produce trans-[NiL2(NO2)2] (1d). The violet species (1) also undergoes dehydration upon heating with deamination resulting (1d).
Polyhedron | 1997
Arunendu Mondal; Chandi Pariya; Nirmalendu Ray Chaudhuri; Nirmalya Prasun Nayak; Alok K. Mukherjee; Ashutosh Ghosh
Abstract [Ni 2 (dien) 2 (NCS) 4 (H 2 O)] ( 1 ) and [Ni(aepn)(NCS) 2 ] n ( 2 ) (where dien = bis(2-aminoethyl)amine and aepn = N -(2-aminoethyl)-1,3-propanediamine) have been synthesised from solution. Single crystal X-ray structure analyses of 1 and 2 reveal that the metal atoms in both the complexes display distorted octahedral geometry with the triamine coordinating facially in 1 and meridionally in 2 . The dinuclear [Ni 2 (dien) 2 (NCS) 4 (H 2 O)] unit in 1 is bridged via a thiocyanate moiety while in 2 the nickel(II) octahedra form a polymeric chain. The species 1 on deaquation at ∼ 165°C followed by cooling yields a conglomerated mass ( 1a ). The species 2 melts at ∼ 230°C which on cooling yields conglomerated mass ( 2a ). Both 1a and 2a are amorphous; the former reverts to 1 in a humid atmosphere.
Polyhedron | 2000
Tapas Kumar Maji; Golam Mostafa; Partha Sarathi Mukherjee; Arunendu Mondal; Alan J. Welch; Ken-ichi Okamoto; Nirmalendu Ray Chaudhuri
Abstract [NiL(SeCN) 2 (H 2 O)] [L=bis(3-aminopropyl)amine (dpt), ( 1 ), (2-aminoethyl)(3-aminopropyl)amine (aepn), ( 2 ) and bis(2-aminoethyl)methylamine) (medien), ( 3 )] have been synthesized and characterized in the solid state by X-ray single crystal analysis ( 1 and 2 ), IR, electronic spectra and magnetic measurement. Structure analyses of ( 1 ) and ( 2 ) reveal that the nickel(II) center is coordinated in a distorted octahedral fashion and the two SeCN groups are attached in trans position. Upon heating they undergo deaquation followed by color change, yielding dinuclear species bridging through selenocyanate. The deaquated dinuclear complexes have been characterized by IR, electronic spectra and magnetic susceptibility measurement.
Acta Crystallographica Section C-crystal Structure Communications | 1999
Alok K. Mukherjee; Nirmalya Prasun Nayak; Arunendu Mondal; Nirmalendu Ray Chaudhuri
The structure of bis[N,N-bis(3-aminopropyl)methylamine]-1κ 3 N,2κ 3 N-di-μ-thiocyanato-1:2κ 2 N:S;1:2κ 2 S:N-dithiocyanato-κN,2κN-dinickel(II), [Ni 2 (NCS) 4 (C 7 H 19 N 3 ) 2 ] or [Ni 2 (μ-SCN) 2 (medpt) 2 (NCS) 2 ], where medpt is bis(3-aminopropyl)methylamine, consists of two crystallographically independent dimer types differing in their orientations. In each dimer, the two Ni II ions are bridged by two SCN- ligands in an end-to-end fashion. The coordination polyhedra about the Ni II atoms are distorted octahedra consisting of three N atoms of the medpt ligand coordinating meridionally, one N atom of the non-bridging thiocyanate ligand, and one N and one S atom of two bridging thiocyanate ligands. The six-membered chelate rings display chair conformations.
Polyhedron | 1998
Arunendu Mondal; Golam Mostafa; Ashutosh Ghosh; N. Ray Chaudhuri; Wing-Tak Wong
Abstract Single crystal structure of [Zn2(dpt)2(μ-OH)](ClO4)3 (dpt = bis(3-aminopropyl) amine) shows that two units of Zn(dpt) are bridged by oxygen atom of the hydroxo group. Each Zn-atom possesses distorted tetrahedral geometry. Analogous complexes [Zn2L2(μ-OH)](ClO4)3 [L = bis(3-aminopropyl) methylamine(medpt), bis(2-aminoethyl)methylamine(medien)] have been synthesised.
Thermochimica Acta | 1996
Arunendu Mondal; Chandi Pariya; Ashutosh Ghosh; Nirmalendu Ray Chaudhuri
Abstract [Cd(aepn) 2 ]X 2 · n H 2 O (where aepn is N -(2-aminoethyl)-1,3-propanediamine, and n = 1 when X is Cl − and Br − , n = 0 when X is 0.5SO 2− 4 , 0.5SeO 2− 4 , NO − 3 and I − ), Cd(aepn)X 2 (where X is Cl − , Br − , I − , 0.5SeO 2− 4 , 0.5SO 2− 4 and SCN − ), and Cd(dpt)X 2 · n H 2 O (where dpt is N -(3-aminopropyl)-1,3-propanediamine, and n = 1 when X is 0.5SO 2− 4 and 0.5SeO 2− 4 , n = 0 when X is Cl − , Br − , I − and SCN − ) have been synthesised and investigated thermally in the solid state. The species Cd(aepn)Cl 2 , Cd(aepn)SO 4 and Cd(aepn)SeO 4 have also been synthesised pyrolytically in the solid state from the corresponding parent bis-complexes. Cd(aepn) (SCN) 2 and Cd(dpt) (SCN) 2 melt on heating and exist as supercooled liquids at ambient temperature. On heating and after deaquation, Cd(dpt)SO 4 ·H 2 O shows two endothermic phase transitions (172–190°C, ΔH = 8.0 kJ mol −1 and 210–245°C, ΔH = 3.5 kJ mol −1 and the low-temperature transition is reversible (182–165°C, ΔH = −7.8 kJ mol −1 ). Conversely, the selenate analogue undergoes an irreversible endothermic phase transition (240–257°C, ΔH = 13.2 kJ mol −1 ). [Cd(aepn) 2 ] (NO 3 ) 2 and Cd(aepn)I 2 show irreversible endothermic phase transitions (198–218°C, ΔH = 5.9 kJ mol −1 for nitrate, and 195–202°C, ΔH = 8.3 kJ mol −1 for iodide). The transitions are assumed to be due to the conformational changes in the triamine chelate rings. The thermal stabilities are rationalized with respect to the carbon chain lengths of the triamine ligands.
Transition Metal Chemistry | 1999
Arunendu Mondal; Inamur Rahaman Laskar; Nirmalendu Ray Chaudhuri; Golam Mostafa; Ashutosh Ghosh; J. Shashidhara Prasad
Abstract[NiL2](NO3)2 (1) and [NiL2](CF3CO2)2 (2) (L = N2-methyldiethylenetriamine] have been synthesized and their X-ray single crystal structures have been determined. The triamines are ligated to NiII s-facially in (1) and meridionally in (2), with a NiN6 chromophore in each complex.
Journal of Thermal Analysis and Calorimetry | 1999
Arunendu Mondal; Debasis Das; N. Ray Chaudhuri
Abstract[NiL2]C4O4·nH2O [where n=2 when L=diethylenetriamine(dien) and N-(3-aminopropyl)-1,3-propanediamine (dpt); n=3 when L=N-(2-aminoethyl)-1,3-propanediamine (aepn); n=0 when L=N2-methyldiethylenetriamine (medien)] and Ni(tmdien)C4O4·2H2O (where tmdien=1,4,7 trimethyl-diethylenetriamine) have been synthesised and investigated thermally in the solid state. Ni(dpt)C4O4·H2O has also been synthesised pyrolytically in the solid state from the corresponding bis complex. All the complexes possess octahedral geometry. The squarate anion takes part in coordination only in monotriamine species. [Ni(medien)2]C4O4 upon heating undergoes phase transition (270–285°C; ΔH=4.9 kJ mol−1) accompanied by colour change pink to grey. Thermal stability decreases with increase in chain length of the triamines.
Journal of The Chemical Society-dalton Transactions | 1998
Debasis Das; Inamur Rahaman Laskar; Ashutosh Ghosh; Arunendu Mondal; Ken-ichi Okamoto; Nirmalendu Ray Chaudhuri
The linkage isomers trans-bis[1-(2-aminoethyl)piperidine]dinitronickel(II) (brown) 1 and trans-bis[1-(2-aminoethyl)piperidine]dinitritonickel(II) (blue) 2 have been synthesized and characterised by X-ray single crystal structure analysis.
Journal of Chemical Research-s | 1998
Arunendu Mondal; Golam Mostafa; Ashutosh Ghosh; Nirmalendu Ray Chaudhuri
Crystal structure analysis of Cd(aepn)(NCS)2 [aepn=(2-aminoethyl)(3-aminopropyl)amine] reveals that each cadmium(II) possesses distorted octahedral geometry and is linked to four different nearest cadmium centres via thiocyanate groups and non-chelated arms of the triamine ligands forming a chain linked system of a hyperbranched polymeric molecule.