Kunal K. Kamar
Indian Association for the Cultivation of Science
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Featured researches published by Kunal K. Kamar.
New Journal of Chemistry | 2002
Chayan Das; Kunal K. Kamar; Amit K. Ghosh; Partha Majumdar; Chen-Hsuing Hung; Sreebrata Goswami
A family of ruthenium N-aryl-1,2-diiminoarene chelate complexes, [RuCl2(bpy)(diim)], 1 (bpy=2,2′-bipyridine, diim=N-aryl-1,2-diiminoarene) were isolated from the reaction of [RuCl3(bpy)] and a primary aromatic amine (ArNH2) in the presence of aerial oxygen. The diim ligand was formed in situ due to oxidative dimerisation of ArNH2. The metal complex, in this reaction, acts as a mediator. The dichloro complexes were characterized based on their physicochemical data. The X-ray structure of one member of the family was determined and the results used to authenticate the formation of the product from an unusual oxidative fusion of aromatic monoamines. The X-ray structure of 1c (substituent R on the aromatic ring=Cl) revealed a cis geometry with respect to two coordinated chlorides. The bond length trends within the chelate as well as the aromatic rings are consistent with a diimine oxidation state of the ligand bound to ruthenium in its bivalent oxidation state. These complexes showed multiple transitions in the near-IR and visible regions. The highly intense transition at around 540 nm has been assigned to a transition involving two heavily mixed metal–ligand orbitals. The ruthenium(III)/ruthenium(II) couple for the dihalo complexes appeared at a high anodic potential (range 0.50 to 0.90 V), which for differently substituted compounds depend on the Hammett ∑σp parameters of the substitution on the diim ligand. The syntheses and characterization of a few heteroleptic tris-chelates, [Ru(bpy)(diim)L](ClO4)2·nH2O (L=a bidentate N,N-donor), involving the reaction of 1 with two moles of the silver reagent, [AgL2](ClO4), are reported. The tris-chelates showed intense charge transfer in their electronic spectra and multiple cathodic voltammetric responses, which have been assigned as reductions of coordinated ligands.
Chemical Communications | 2001
Partha Majumdar; Kunal K. Kamar; Alfonso Castiñeiras; Sreebrata Goswami
Two novel examples of heteronuclear tetrametallic M2Ag2 (M = Ru, Os) complexes are described which show strong argentophilic interactions.
Journal of Chemical Sciences | 2002
Kunal K. Kamar; Amrita Saha; Sreebrata Goswami
This presentation reports some novel examples of organic ring amination reactions via metal mediation. The organic transformations are highly regioselective and can be controlled by the proper selection of the mediator complex. The two isomeric organic ligands viz. HL1 and HL2 were isolated in their pure states by the removal of the metal ions. These were fully characterized. The ligand HL1 has lowpKa, 8.5. Upon deprotonation, it behaves as a potentialbis chelating N,N,N-donors. The coordination chemistry of the HL1 ligand involving some 3d-metal ions is described. Two unusual low-spin complexes of manganese(II) and iron(III) are reported. The ferric complex displayed a rhombic EPR while, the corresponding manganese compound showed a complex pattern due to hyperfine coupling. All the complexes displayed large number of redox responses. A brief mention about the future projection of this work is noted.
Inorganic Chemistry | 2003
Kunal K. Kamar; Srijit Das; Chen-Hsiung Hung; Alfonso Castiñeiras; M.D. Kuz'min; C. Rillo; J. Bartolomé; Sreebrata Goswami
Inorganic Chemistry | 2002
Amit K. Ghosh; Kunal K. Kamar; Parimal Paul; Shie-Ming Peng; Gene-Hsiang Lee; Sreebrata Goswami
Inorganic Chemistry | 2002
Kunal K. Kamar; Amrita Saha; Alfonso Castiñeiras; Chen-Hsiung Hung; Sreebrata Goswami
New Journal of Chemistry | 2002
Chayan Das; Kunal K. Kamar; Amit K. Ghosh; Partha Majumdar; Chen-Hsuing Hung; Sreebrata Goswami
Dalton Transactions | 2004
Kunal K. Kamar; Larry R. Falvello; Philip E. Fanwick; Jinkwon Kim; Sreebrata Goswami
Indian journal of chemistry. Sect. A: Inorganic, physical, theoretical & analytical | 2006
Sudipta Chatterjee; Kunal K. Kamar; Michael B. Hursthouse; Mark E. Light; Sreebrata Goswami
Dalton Transactions | 2004
Kunal K. Kamar; Larry R. Falvello; Philip E. Fanwick; Jinkwon Kim; Sreebrata Goswami