• Poulami Pattanayak

      Articles written in Journal of Chemical Sciences

    • Osmium and cobalt complexes incorporating facially coordinated N,N,O donor azo-imine ligands: Redox and catalytic properties

      Poulami Pattanayak Debprasad Patra Jahar Lal Pratihar Andrew Burrows Mary F Mahon Surajit Chattopadhyay

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      Reactions of 1-{[2-(arylazo)phenyl]iminomethyl}-2-phenol, HL [where H represents the dissociable phenolic protons of ligands and aryl groups of HL are C6H5 (HL1), 𝑝-CH3C6H5 (HL2), 𝑝-ClC6H5 (HL3)] with Os(H)(CO)(Br)(PPh3)3 in toluene and with Co(ClO4)3.6H2O in methanol afforded new facially coordinated complexes of composition [(L)Os(CO)(Br)(PPh3)] and [(L)2Co]ClO4. The anionic ligand (L), binds the metal in tridentate (N, N, O) manner in [(L)Os(CO)(Br)(PPh3)] and [(L)2Co]ClO4 complexes. All the Os(II) and Co(III) complexes are diamagnetic and show characteristic 1H NMR signals and intense MLCT transitions in the visible region. The cyclic voltammograms exhibited one quasi reversible oxidative response near 0.10 V vs SCE for [(L)Os(CO)(Br)(PPh3)] and [(L)2Co]ClO4 complexes displayed serial reductive responses within −0.06 to −1.61 V vs SCE. Single point DFT calculation was carried out to examine the nature of redox orbitals. Conversion of ketones to corresponding alcohols has been studied using [(L)Os(CO)(Br)(PPh3)] as catalyst.

    • Synthesis and structure of copper(II) complexes: Potential cyanide sensor and oxidase model'


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      The new complexes of compositions $[(L_{a})_{2}Cu]$ and $[(L_{b})_{2}Cu]$ were prepared by treating with2-hydroxy-5-methyl-3-(2-aryldiazenyl)phenylimino) methyl) benzaldehyde $(HL_{a})$ and ethyl-2-cyano-3-(2-hydroxy-5-methyl-3-(-(2-aryldiazenyl) phenylimino) methyl) phenyl) acrylate $(HL_{b})$ ligands [where aryl isphenyl for $HL_{a}^{1}$ and $HL_{b}^{1}$ ; p-methyl phenyl for $HL_{a}^{2}$ and $HL_{b}^{2}$ ; and p-chloro phenyl for $HL_{a}^{3}$ and $HL_{b}^{3}$ ] with $Cu(OAc)_{2}.H_{2}O$, respectively. Both the bis copper(II) complexes consist of tridentate (N,N,O) anionic ligands, $L^{-}_a$ or $L^{-}_b$ . X-ray structures of the representative complexes $[(L^{1}_{a})_{2}Cu]$ and $[(L^{2}_{b})_{2}Cu]$ were determined toconfirm the molecular species unequivocally. The molecular structure of copper complexes exhibited tetragonallydistorted (Jahn-Teller) geometry consistent with the $d^{9}$ configuration of Cu(II) metal ion. Oxidation ofbenzyl alcohols using the newly synthesized complexes as catalyst has been studied. Photoluminescence propertiesof $[(L^{2}_{a})_{2}Cu]$ and $[(L^{2}_{b})_{2}Cu]$ were exploited for selective cyanide recognition. The $[(L_{b})_{2}Cu], complexesdisplayed antibacterial activity toward gram positive and gram negative bacteria

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