• Jaipal

      Articles written in Journal of Chemical Sciences

    • Synthesis, magnetic and spectral studies on polystyrene-anchored coordination complexes of bi-, tri-, tetra- and hexavalent metal ions with unsymmetrical dibasic tetradentate ONNO donor Schiff base derived from 3-formylsalicylic acid, ethylenediamine and 2-benzoylacetanilide

      Dinesh Kumar Arun Syamal Jaipal Lalit Kumar Sharma

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      Polystyrene-anchored Cu(II), Zn(II), Cd(II), Ni(II), Mn(II), MoO2(II), UO2(II), Fe(III) and Zr(IV), complexes of the unsymmetrical dibasic tetradentate ONNO donor Schiff base derived from the condensation of chloromethylated polystyrene, 3-formylsalicylic acid, ethylenediamine and 2-benzoylacetanilide (PS-LH2) has been synthesized. The polystyrene anchored complexes have the formulae: PS-LM (where M = Cu, Zn, Cd, Ni, MoO2, UO2), PS-LFeCl.DMF, PS-LMn$.2$DMF and PS-LZr(OH)$_2.$DMF. The polystyrene-anchored coordination compounds have been characterized by elemental analysis, IR, reflectance, ESR and magnetic susceptibility measurements. The per cent reaction conversion of polystyrene anchored Schiff base to polystyrene supported coordination compounds lies between 28.98 and 85.9. The coordinated dimethylformamide is completely lost on heating the complexes. The shifts of the ν(C=N)(azomethine) and ν(C-O)(phenolic) stretches have been monitored in order to find out the donor sites of the ligands. The Cu(II) complex is paramagnetic with square planar structure; the Ni(II) complex is diamagnetic with square planar structure; the Zn(II) and Cd(II) complexes are diamagnetic and have tetrahedral structure; the Mn(II) and Fe(III) complexes are paramagnetic and have octahedral structure; the MoO2(II) and UO2(II) complexes are diamagnetic and have octahedral structure and the Zr(IV) complexes are diamagnetic and have pentagonal bipyramidal structure.

    • Carbazole-based sensitizers for potential application to dye sensitized solar cells

      Naresh Duvva Ravi Kumar Kanaparthi Jaipal Kandhadi Gabriele Marotta Paolo Salvatori Filippo De Angelis Lingamallu Giribabu

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      Two push-pull molecules employing carbazole and alkyl thiophene (CAR-THIOHX) or carbazole and triphenylamine (CAR-TPA) as donor moieties, with the cyanoacrylic group as the acceptor, have been designed and synthesized by simple organic transformations. Photophysical and electrochemical studies revealed the potential of these two systems in dye sensitized solar cells (DSSC). Under standard irradiation conditions, CAR-TPA and CAR-THIOHX exhibited 2.12 and 1.83% of overall power conversion efficiencies respectively. The moderate photovoltaic efficiency of the sensitizers has been attributed to the poor light absorption of the sensitizers in the visible region. Density functional theory (DFT) calculations have shown a strong intramolecular charge transfer character, with the HOMOs of both the sensitizers exclusively localized on the corresponding donor moieties and LUMOs on the cyanoacrylic acid acceptor. On the other hand, the calculated high dihedral angle between the carbazole donor and the phenyl bridge for these sensitizers impedes the conjugation along the dyes backbone, and thus leads to less extended and intense absorption spectra in the visible region.

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