• Ankit Kumar

      Articles written in Journal of Chemical Sciences

    • Influence of fuel ratios on auto combustion synthesis of barium ferrite nano particles

      D Bahadur S Rajakumar Ankit Kumar

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      Single-domain barium ferrite nano particles have been synthesized with narrow particle-size distribution using an auto combustion technique. In this process, citric acid was used as a fuel. Ratios of cation to fuel were maintained variously at 1:1, 1:2 and 1:3. The pH was 7 in all cases. Of all three cases, a cation to citric acid ratio of 1:2 gives better yield in the formation of crystalline and single domain particles with a narrow range of size distribution. Most particles are in the range of 80 to 100 nm. Maximum magnetization and coercivity values are also greater for 1:2 ratios. These values measured at room temperature are found to be 55 emu/gram and 5000 Oe respectively. XPS and ESR studies support the results.

    • One-dimensional manganese(III) and iron(III) coordination polymers assembled by N2O2-donor Schiff bases and 4,4Ꞌ-bipyridine: syntheses, structures and properties


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      Reactions of Mn(ClO4)2.6H2O and Fe(ClO4)3.6H2O with the tetradentate N2O2-donor Schiffbases N,NꞋ-bis(salicylidene)-ortho-phenylenediamine and N,NꞋ-bis(salicylidene)ethylenediamine (H2salophenand H2salen, where 2 Hs represent the two dissociable phenolic protons), respectively and the bridging ligand4,4Ꞌ-bipyridine (bipy) in presence of triethyl amine in methanol under ambient conditions produce onedimensional coordination polymers {[Mn(salophen)(μ-bipy)]ClO4}n (1) and {[Fe(salen)(μ-bipy)]ClO4}n (2)in ~60% yields. Both complexes have been characterized by elemental analysis and spectroscopic (IR andDR) measurements. The linear polymeric structures of 1 and 2 have been confirmed by single-crystal X-raycrystallography. The metal centres in these polymers are in distorted octahedral N4O2 coordination spheres.Each of the two dibasic tetradentate ligands (salophen2- and salen2-) forms an ONNO square-plane aroundthe metal centre, while the two axial coordination sites are occupied by N-atoms of the two bridging bipyligands. Variable temperature magnetic susceptibility measurements reveal the high-spin configuration ofmanganese(III) and iron(III) and Curie paramagnetic behaviour of each of the two coordination polymers.

      Facile one-pot syntheses of two new one-dimensional coordination polymers {[Mn(salophen)(μ-bipy)]ClO4}n and {[Fe(salen)(μ-bipy)]ClO4}n have been described. Both polymers were characterised by elemental analyses and solid state spectroscopic and cryomagnetic measurements. Linear chain-like structures of the high-spin Mn(III) and Fe(III) containing Curie paramagnetic polymers were confirmed by single crystal X-ray crystallography.

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