http://nopr.niscpr.res.in/handle/123456789/57921 2026-10-10T23:54:44Z http://nopr.niscpr.res.in/handle/123456789/57933 Title: Lanthanide luminescence based probe for detection of picric acid Authors: Ananthanarayanan, R; Panda, Sitakanta; Sivaramakrishna, M; Panigrahi, B S Abstract: Europium fluorescence is significantly enhanced through ligand sensitization using aromatic benzene mono and di carboxylic acids as ligands in aqueous solution. By optimising metal to ligand ratio and solution pH, it is established that the enhancement is maximum with isophthalic and terephthalic acid. Phosphorescence of isophthalic acid is recorded and its triplet energy level is found to be at 25633 cm-1; just above the fluorescing energy level of Eu3+. On complexation with these ligands though the europium luminescence is enhanced by orders of magnitude, the europium lifetime increased marginally. Addition of picric acid resulted in the quenching of europium luminescence in europium-isophthalic acid complex. Based on this quenching, a fluorimetric method is developed for the estimation of picric acid in aqueous solution. Picric acid in aqueous solution could be estimated down to 0.23 ppm. Common cations and anions found in natural waters did not interfere in the analysis. The precision in measurement is within 5% RSD in the entire range of measurement. Page(s): 1041-1047 2021-08-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/57932 Title: Fe(III), Co(II) & Cu(II) Complexes of N,N‟-Bis[2-salicylideneamino]ethane-1,2-diamine: Preparation, characterisation and in vitro antibacterial activity Authors: Joshi, Shital; Sharma, Komal; Jadham, Jaishri; Sharma, Uma Abstract: Salicylaldehyde derived hexadentate Schiff base N,N‟-Bis[2-salicylideneamino]ethane-1,2-diamine (TTS) and its complexes with Fe(III), Co(II) and Cu(II) metal ions have been prepared and characterised by elemental analysis, UV-visible, IR, 1H NMR, EPR spectral analysis, mass spectrometry and XRD method. In vitro antibacterial activity of the Schiff base and its metal complexes against Gram positive bacterial strains Staphylococus aureus, Bacillus subtilis and Gram negative bacterial strains Enterobacter, Escherichia coli has revealed that the metal complexes are more active to the bacterial strains as compared to that of the Schiff base. The Co-TTS has the highest antibacterial activity against Escherichia coli, while the Fe-TTS complex is highly active against Enterobacter, Staphylococcus aureus and Bacillus subtilis. Page(s): 1048-1054 2021-08-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/57930 Title: Hantzsch synthesis of 1,4-dihydropyridine derivatives over ZnO/ZrO2 catalyst under solvent free condition Authors: Sunkara, Prasad; Keshavulu, M; Puppala, Veerasomaiah; Kumar, P Vijay; Basude, Manohar Abstract: Hantzsch synthesis of 1,4-dihydropyridine derivatives is accomplished using novel and efficient ZnO/ZrO2 catalyst. The catalysts prepared by facile precipitation and wet impregnation method have been characterized by using techniques like XRD, SEM, EDS, UV-diffuse reflectance spectra, FTIR, XPS, BET surface area. Ex situ Pyridine absorption FTIR spectroscopy is used to determine the Bronsted and Lewis acidic sites. Enhanced activity of the zirconia supported zinc catalyst is attributed to tetragonal phase, more acidic sites and high surface area of the catalyst. The products attained in good to excellent yields in short duration under solvent free condition, minimizing the disposal problem and energy dissipation. The catalyst can be reused umpteen times without significant loss in activity. Page(s): 1055-1063 2021-08-01T00:00:00Z http://nopr.niscpr.res.in/handle/123456789/57927 Title: Silver(I) catalyzed oxidation kinetics of the crystal violet dye by peroxydisulphate in aqueous and micellar media Authors: Hameed, Salem A; Ewais, Hassan A Abstract: The kinetics of the oxidative decolcourisation of crystal violet (CV+) as a cationic dye by peroxydisulphate using silver(I) catalyst in aqueous acidic medium has been studied. The effects of different parameters like hydrogen ion, silver(I), reactants concentration, micelles and temperatures are investigated. The reaction between [CV]+ and persulphate is investigated under pseudo-first-order kinetics by taking a large excess of [S2O8 2-] over [CV+]. The effect of surfactant micelles such as SDS and Triton X-100 on the reaction rate is investigated. The rate of reaction decreases with increasing [SDS] but had no effect with Triton X-100. Heat and entropy of activation and are calculated. An outer-sphere process for the electron transfer is the proposed mechanism for this reaction. Page(s): 1064-1071 2021-08-01T00:00:00Z