Subratanath Koner

Jadavpur University, Kolkata, West Bengal, India

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Publications (106)279.73 Total impact

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    Soma Das · Tanmoy Maity · Subratanath Koner
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    ABSTRACT: N-Arylation reaction of N-heterocyclic compounds has been carried out in excellent yield using copper anchored SBA-15 catalyst. Sequential N-arylation reactions employing single catalyst under heterogeneous condition provides a straightforward access to a series of important arylazolium salts. Simplicity of the method and outstanding character of the catalyst facilitate the reactions to go smoothly which encompass a broad range of functional groups. Catalyst can be recovered and reused several times without any significant loss in its catalytic activity.
    Full-text · Article · Dec 2015
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    DESCRIPTION: single crystal, structurally diverse complexes, Schiff base, O-arylation, homogeneous catalysis, green condition
    Full-text · Research · Oct 2015
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    Rupam Sen · Debraj Saha · Subratanath Koner · Paula Brandão · Zhi Lin
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    ABSTRACT: A new amino-functionalized strontium-carboxylate-based metal-organic framework (MOF) has been synthesized that undergoes single crystal to single crystal (SC-to-SC) transformation upon desolvation. Both structures have been characterized by single-crystal X-ray analysis. The desolvated structure shows an interesting 3D porous structure with pendent NH2 groups inside the pore wall, whereas the solvated compound possesses a nonporous structure with DMF molecules on the metal centers. The amino group was postmodified through Schiff base condensation by pyridine-2-carboxaldehyde and palladium was anchored on that site. The modified framework has been utilized for the Suzuki cross-coupling reaction. The compound shows high activity towards the CC cross-coupling reaction with good yields and turnover frequencies. Gas adsorption studies showed that the desolvated compound had permanent porosity and was microporous in nature with a BET surface area of 2052 m(2) g(-1) . The material also possesses good CO2 (8 wt %) and H2 (1.87 wt %) adsorption capabilities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
    Full-text · Article · Mar 2015 · Chemistry - A European Journal
  • Debraj Saha · Tanmoy Maity · Subratanath Koner
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    ABSTRACT: New carboxylate systems with alkaline earth metals, namely, [Ca2Na2(L)2(H2O)6]n·nH2O (1, H3L = chelidamic acid) and [Sr3(L)2(H2O)9]n·2nH2O (2), have been prepared by hydrothermal reactions and characterized. The compounds featured different three-dimensional (3D) structural motifs and new topologies. The amount of void space for the dehydrated materials of 1 and 2 was calculated to be ca. 19 and 35 %, respectively. The dehydrated materials are thermally stable to more than 450 °C. The dehydrated species of 1 and 2 displayed excellent N2, H2, and CO2 sorption capacity at 1 atm pressure. Furthermore, both compounds efficiently catalyze the hydrogenation of alkenes under mild heterogeneous conditions (60 °C, 1 atm H2). The porous catalysts demonstrate size selectivity towards substrates owing to presence of active sites inside the pores of the MOF.
    No preview · Article · Jan 2015 · Berichte der deutschen chemischen Gesellschaft
  • Rupam Sen · Debraj Saha · Subratanath Koner · Dasarath Mal · Paula Brandão · Zhi Lin
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    ABSTRACT: The role of pH in the formation of metal–organic frameworks (MOFs) has been studied on magnesium-based carboxylate framework systems [Mg(Pdc)(H2O)3]n (1) and [Mg(Pdc)(H2O)]n (2) (Pdc=pyridine-2,3-dicarboxylate). The investigation reveals the formation of two different compounds of one- or three-dimensions starting from the same reaction mixture that differs only in pH. Isolated compounds have been characterized by IR and elemental analysis; both compounds were also successfully characterized by single-crystal X-ray diffraction. This study shows that the gradual increase in pH helps to construct a higher-dimensional network. Catalytic activity of compounds 1 and 2 was tested for the Claisen–Schmidt reaction. Compound 2 was successfully dehydrated to produce a coordinately unsaturated compound 2 a, which shows higher catalytic activity than 1 or 2 in heterogeneous medium.
    No preview · Article · Jan 2015 · ChemPlusChem
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    Tanmoy Maity · Debraj Saha · Soma Das · Susmita Bhunia · Subratanath Koner
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    ABSTRACT: A highly porous Zn-based iso-reticular metal–organic framework (IRMOF-3) has been selected for covalent modification. Pyridine-2-aldehyde has been used to decorate the free amine group of IRMOF-3 in the porous matrix. Schiff base moiety thus generated has been availed to anchor copper(II) ions to prepare the desired catalyst that catalyzes O-arylation reactions heterogeneously under mild reaction conditions. Porous catalyst demonstrates size selectivity in products when various substrates undergo O-arylation with α and β-naphthol.
    Full-text · Article · Jan 2015 · Catalysis Communications
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    Soma Das · Susmita Bhunia · Tanmoy Maity · Subratanath Koner
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    ABSTRACT: A new hybrid catalyst has been prepared by tethering a palladium(II) Schiff-base complex via post-synthesis modification of mesoporous silica, MCM-41. The Schiff-base has been derived from o-vanillin and 3-[(2-aminoethylamino)propyl]trimethoxysilane (ATMS) which is chemically anchored on MCM-41 via silicon alkoxide route. The anchored Schiff-base imposed a stable planar coordination sphere on the central palladium ion. The catalyst has been characterized by elemental analysis, small angle Xray diffraction, FT-IR, UV-vis, N-2 sorption study, transmission electron microscopy (TEM) studies and scanning electron microscopy (SEM) studies. X-ray and TEM measurement showed the mesoporosity of the catalyst. The activity of the catalyst has been assessed in the Suzuki C-C cross coupling reaction using various phenyboronic acid in heterogeneous condition. High selectivity for the biaryl products containing both electron-donating and electron-withdrawing substituents, high turnover, mild reaction conditions and possibility of easy recycle makes the catalyst highly desirable to address the industrial needs and environmental concerns.
    Full-text · Article · Nov 2014 · Journal of Molecular Catalysis A Chemical
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    Debraj Saha · Tanmoy Maity · Subratanath Koner
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    ABSTRACT: Two alkaline earth metal-based carboxylate systems, [Mg(HL)(H2O)2]n () and [Ca(H2L)2]n () (H3L = chelidamic acid) have been hydrothermally synthesized, and characterized by single-crystal X-ray diffraction, IR, elemental analysis, and thermo-gravimetric analysis. Compound has a 2D structure incorporating two water molecules. The dehydrated species, , generated from by removal of the coordinated water, has been characterized by thermo-gravimetric analysis, IR, elemental analysis and variable temperature powder X-ray diffraction. Both and its dehydrated species catalyze the Claisen-Schmidt reaction under heterogeneous conditions, but is a more effective catalyst under environmentally friendly conditions. The catalyst can readily be recovered and reused in successive cycles without detectable loss of activity. Compound has a 3D structure and is thermally stable up to 540 °C, but is inactive catalytically.
    Full-text · Article · Jul 2014 · Dalton Transactions
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    Tanmoy Maity · Debraj Saha · Subratanath Koner
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    ABSTRACT: A highly porous Zn-based metal–organic framework (MOF) IRMOF-3 was covalently decorated with pyridine-2-aldehyde. The free amine group of IRMOF-3 upon condensation with pyridine-2-aldehyde affords a bidentate Schiff-base moiety in the porous matrix. The Schiff base moieties are availed to anchor copper(II) ions to display the catalyst’s utility towards catalytic reactions. The catalyst was characterized by UV/Vis and IR spectroscopy, powder XRD spectrometry, SEM energy-dispersive X-ray spectrometry, and nitrogen sorption measurements. The catalyst exhibits excellent activity in catalyzing the N-arylation reaction of nitrogen-containing heterocycles with aryl bromides in DMSO medium, under mild condition (90 °C) in the presence of Cs2CO3. The porous catalyst demonstrates size selectivity towards substrate as a result of the presence of active sites inside the pores of the MOF. The anchored complex seems to be not leached or decomposed during the catalytic reactions up to five successive catalytic cycles, demonstrating practical advantages over homogeneous catalysis.
    Full-text · Article · Jul 2014 · ChemCatChem
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    ABSTRACT: A cobalt(II) Schiff base complex has been immobilized onto the surface of Si-MCM-41 to prepare a new catalyst. The amine group-containing organic moiety 3-aminopropyl-triethoxysilane had first been anchored on the surface of Si-MCM-41 via a silicon alkoxide route. Upon condensation with salicylaldehyde, the amine group affords a bidentate Schiff-base moiety in the mesoporous matrix, which is subsequently used for anchoring of cobalt(II) centers. The prepared catalyst has been characterized by UV-vis, infrared (IR), EPR spectroscopic and small angle X-ray diffraction (XRD) analyses, and N2 sorption studies. The catalytic activity was tested in epoxidation reactions of olefinic compounds, including styrene and allyl alcohol, with molecular oxygen at atmospheric pressure in dimethylformamide medium in the absence of additional sacrificial reductant. The reactions seemed to proceed through a radical formation mechanism. The immobilized catalyst showed good activity and epoxide selectivity in the alkene epoxidation. Notably, the catalyst can be recovered and reused without any loss of activity.
    No preview · Article · Jun 2014 · Catalysis Science & Technology
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    Soma Das · Sreyashi Jana · Buddhadeb Dutta · Subratanath Koner
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    ABSTRACT: A facile method for synthesis of end-substituted oligo(p-phenylenevinylene) (OPV) with hydrophilic poly(ethylene glycol) (PEG) segment has been established using Pd(0)-catalyzed Heck coupling reaction. The OPVs are symmetrically end-substituted with a hydrophilic poly(ethylene glycol) segment. The prepared oligo(phenylenevinylene)s exhibit the expected photoluminescence properties.
    Full-text · Article · Jan 2014 · Research on Chemical Intermediates
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    Debraj Saha · Tanmoy Maity · Soma Das · Subratanath Koner
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    ABSTRACT: Three magnesium based carboxylate framework systems were prepared through a temperature-dependent synthesis. The compounds were synthesized by a hydrothermal method and characterized by single crystal X-ray diffraction analysis. A stepwise increase in the temperature of the medium resulted a stepwise increase in the dimensionality of the network, ultimately leading to the formation of a new 2D layered alkaline earth metal-organic framework (MOF) compound, {[Mg2(HL)2(H2O)4]·H2O}n () (H3L = pyrazole-3,5-dicarboxylate). Compound selectively adsorbs hydrogen (H2) (ca. 0.56 wt% at 77 K) over nitrogen at 1 atm and demonstrates a strong blue fluorescent emission band at 480 nm (λmax) upon excitation at 270 nm. Notably, the 2D framework compound efficiently catalyzes the aldol condensation reactions of various aromatic aldehydes with ketones in a heterogeneous medium under environmentally friendly conditions. The catalyst can be recycled and reused several times without any significant loss of activity.
    Full-text · Article · Aug 2013 · Dalton Transactions
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    Debraj Saha · Tanmoy Maity · Rajesh Bera · Subratanath Koner
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    ABSTRACT: a b s t r a c t A new Co(III) Schiff-base complex, [Co(HL) 2 ]NO 3 ÁH 2 O (1) (H 2 L = 1-(N-3-methoxy-salicylideneimino)-eth-ane-2-ol), has been synthesized and characterized by several physicochemical methods. X-ray crystal structure analysis revealed that complex 1 features a distorted octahedral coordination geometry and the metal center is surrounded by two tridented N,O,O-donor Schiff base ligands (HL À). [Co(HL) 2 ]NO 3 ÁH 2 O (1) is capable of activating dioxygen in air to catalyze the epoxidation of various alkenes using isobutr-aldehyde as a co-reductant under homogeneous conditions. It was observed that the yield of the epoxides and their selectivity is highest in acetonitrile medium.
    Full-text · Article · Apr 2013 · Polyhedron
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    Debraj Saha · Rupam Sen · Tanmoy Maity · Subratanath Koner
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    ABSTRACT: An ecofriendly solid catalyst has been synthesized by anchoring palladium(II) into post synthetically modified metal organic framework IRMOF-3. Pore of IRMOF-3 was first modified with pyridine-2-aldehyde. The amine group of IRMOF-3 upon condensation with pyridine-2-aldehyde afforded a bidentate Schiff base moiety in the porous matrix. The Schiff base moieties were used to anchor palladium(II) ions. The prepared catalyst has been characterized by UV-vis, IR spectroscopy, X-ray powder diffraction and nitrogen sorption measurements. Framework structure of the catalyst is not being destroyed in the multistep synthesis procedure as evidenced in X-ray powder diffraction studies. The catalyst has shown high activity towards Suzuki and Stille cross-coupling reaction in 20% H2O/EtOH and EtOH medium, respectively, at 80 °C. The immobilized complex did not leach or decompose during the catalytic reactions, showing practical advantages over the homogeneous catalysis.
    Full-text · Article · Feb 2013 · Langmuir
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    ABSTRACT: Reaction of ethanolic solution of hydrated metal salts Mn(NO3)2/Fe(BF4)2 with sodium dicyanamide (dca) and 18-crown-6 ether (18C6) in water results in the isolation of 1:1 associates [Mn(dca)2(H2O)4]·18C6 (1) and [Fe(dca)2(H2O)4]·18C6 (2). Single crystal X-ray structure analysis revealed a high degree of isostructurality between the two 18C6 templated metal complexes (1) and (2) exhibiting second sphere coordination via intermolecular O (water)H⋯O (crown) hydrogen bonds. The octahedral Mn(II)/Fe(II) complexes are sandwiched between adjacent 18C6 molecules into one-dimensional polymeric chains along the [1 0 0] directions, which are further linked through intermolecular O (water)H⋯N (dca) hydrogen bonds, thus forming a two-dimensional supramolecular framework. The electronic structures of the complexes calculated at the DFT level showed a HOMO–LUMO energy separation of 2.45 eV in (1) and 0.83 eV in (2), which implied a higher kinetic stability of complex (1) than that of (2).
    No preview · Article · Feb 2013 · Journal of Molecular Structure
  • Satyajit Haldar · Subratanath Koner
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    ABSTRACT: The addition of phenols to aryl-substituted alkynes to form 1,1-diarylalkenes was carried out by using the Fe-Al-MCM-41 catalyst. The catalyst showed remarkable improvement in time and yield in comparison to other solid catalysts. The heterogeneous catalyst can be reused at least three times without a significant loss in activity.
    No preview · Article · Jan 2013 · Beilstein Journal of Organic Chemistry
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    Tanmoy Maity · a] Debraj Saha · a] Soma Das · Subratanath Koner
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    ABSTRACT: A new 3D alkaline earth metal–organic framework (MOF), [Ba(Hdcp)H2O]n (1) (H3dcp = 3,5-pyrazoledicarboxylic acid), has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction analysis. A crystallographic study reveals that each metal ion in 1 is coordinated by eight O atoms and one N atom. Each 3,5-pyrazoledicarboxylato (Hdcp2–) ligand coordinates to six alkaline earth metal centers through two carboxylate groups, each of which adopts a μ3-η2:η1-bridging coordination mode to afford a 3D network. Thermogravimetric analysis reveals that 1 is thermally stable up to ca. 230 °C. An emission band at ca. 466 nm (λmax) was observed in the photoluminescence spectrum of 1 in the solid state at room temperature. Compound 1 heterogeneously catalyzes the aldol condensation reactions of various aromatic aldehydes with acetone, cyclohexanone, acetophenone, and cyclopentanone.
    Full-text · Article · Oct 2012 · Berichte der deutschen chemischen Gesellschaft
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    Debraj Saha · Tanmoy Maity · Rupam Sen · Subratanath Koner
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    ABSTRACT: a b s t r a c t A new three-dimensional alkaline-earth metal–organic framework (MOF) compound, [Ba(pdc)] n (1) (H 2 pdc = pyridine-2,5-dicarboxylate), has been hydrothermally synthesized and structurally character-ized by single crystal X-ray diffraction analysis. X-ray single-crystal analysis reveals that each metal ion in compound 1 is coordinated by seven O atoms from seven different carboxylate groups. While each pyridine-2,5-dicarboxylato (pdc 2À) ligand coordinates to seven alkaline earth metal centers through two carboxylate groups adopting l 4 -g 2 :g 2 -bridging and l 3 -g 2 :g 1 -bridging coordination modes to afford a 3D network. Thermogravimetric analysis reveals that compound 1 is thermally stable up to around 560 °C. Compound 1 efficiently catalyzes aldol condensation reactions of various aromatic aldehydes with acetone and cyclohexanone under environment friendly heterogeneous condition, giving remark-able yields (up to 96%) with high selectivity (100%) within a short reaction time (6 h). The catalyst was recycled for five successive runs without significant loss of activity. There was no evidence of leaching of metal ions or no loss of structural integrity of the catalyst during the catalytic reaction.
    Full-text · Article · Jul 2012 · Polyhedron
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    Debraj Saha · Rupam Sen · Tanmoy Maity · Subratanath Koner
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    ABSTRACT: A new three-dimensional alkaline-earth metal-organic framework (MOF) compound, [Mg(Pdc)(H(2)O)](n) (1) (H(2)Pdc = pyridine-2,5-dicarboxylic acid), has been synthesized and structurally characterized by single crystal X-ray diffraction analysis. Compound 1 features a 3D porous framework afforded by the Mg(2)-diad centers through formation of interconnected chair like structural motifs. A nitrogen adsorption study confirms the microporosity of compound 1 with a BET surface area of 211 ± 12 m(2) g(-1). Upon dehydration, the BET surface area of 1 is enhanced to a value of 463 ± 36 m(2) g(-1) due to removal of coordinated water molecule. After rehydration, the compound reverts to its original form as evidenced by powder X-ray diffraction and IR spectroscopic analysis and N(2) sorption measurement. Compound 1 retains its pore structure with a variable BET surface area in several cycles of dehydration and rehydration processes indicating robustness of the framework in [Mg(Pdc)(H(2)O)](n) (1). Compound 1 catalyzes the aldol condensation reactions of various aromatic aldehydes with acetone and cyclohexanone in heterogeneous conditions. Notably, the catalytic activity of the compound is enhanced upon dehydration. The catalyst can be recycled and reused several times without significant loss of activity.
    Full-text · Article · May 2012 · Dalton Transactions
  • Rupam Sen · Debraj Saha · Subratanath Koner
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    ABSTRACT: The role of pH in the formation of metal-organic frameworks (MOFs) has been studied for a series of magnesium-based carboxylate framework systems. Our investigations have revealed the formation of five different zero-dimensional (0D) to three-dimensional (3D) ordered frameworks from the same reaction mixture, merely by varying the pH of the medium. The compounds were synthesized by the hydrothermal method and characterized by single-crystal X-ray diffraction. Increase of the pH of the medium led to abstraction of the imine hydrogen from the ligand and a concomitant increase in the OH(-) ion concentration in the solution, facilitating the construction of higher dimensional framework compounds. A stepwise increase in pH resulted in a stepwise increase in the dimensionality of the network, ultimately leading to the formation of a 3D porous solid. A gas adsorption study of the 3D framework compound confirmed its microporosity with a BET surface area of approximately 450 m(2)  g(-1). Notably, the 3D framework compound catalyzes aldol condensation reactions of various aromatic aldehydes with acetone under heterogeneous conditions.
    No preview · Article · May 2012 · Chemistry - A European Journal

Publication Stats

2k Citations
279.73 Total Impact Points

Institutions

  • 2001-2015
    • Jadavpur University
      • Department of Chemistry
      Kolkata, West Bengal, India
    • National Institute of Advanced Industrial Science and Technology
      Tsukuba, Ibaraki, Japan
  • 1994-2003
    • University of Tsukuba
      Tsukuba, Ibaraki, Japan
  • 1998-1999
    • CSIR - National Chemical Laboratory, Pune
      Poona, Maharashtra, India
  • 1988-1996
    • Indian Association for the Cultivation of Science
      • Department of Inorganic Chemistry
      Kolkata, West Bengal, India