Papers by Karunakaran Chockalingam
Applied Physics A, 2018
Nanocrystalline ZnO is an innocuous, stable, water-insoluble antibacterial agent and enhancement ... more Nanocrystalline ZnO is an innocuous, stable, water-insoluble antibacterial agent and enhancement of its bactericidal activity without hampering the non-toxicity and stability is of scientific as well as technological interest. Hexagonal ZnO nanoplatelets implanted with CdO were obtained by a two-step synthesis of precipitation accompanied by hydrothermal process. The synthesized nanoplates were characterized by energy dispersive X-ray spectroscopy, X-ray diffraction, selected area electron diffraction, scanning electron microscopy and transmission electron microscopy. Insertion of CdO nanocore in ZnO lattice increases largely the charge transfer resistance but does not influence the band gap energy. The implantation suppresses the violet emission but enhances the blue-green emission, which is due to variation in the relative abundance of different defects. The bactericidal activity of the synthesized novel CdO-implanted ZnO nanocomposite is larger than those of precursor CdO and pristine ZnO.
Polish journal of chemistry
Afinidad -Barcelona-
ABSTRACT
Polish journal of chemistry
ABSTRACT
Afinidad -Barcelona-
ABSTRACT
Oxidation Communications
ABSTRACT
Superlattices and Microstructures, 2015
Al 2 O 3 /TiO 2 core/shell nanoparticles were prepared by sol-gel technique. The scanning electro... more Al 2 O 3 /TiO 2 core/shell nanoparticles were prepared by sol-gel technique. The scanning electron micrograph reveals the synthesized nanomaterial as polycrystalline. While the obtained material displays the X-ray diffractogram of anatase TiO 2 shell the energy dispersive X-ray spectrum shows the presence of Al in the Al 2 O 3 core. The band gap energy of the prepared composite nanoparticles is 3.2 eV and the observed photoluminescence is characteristic of TiO 2 shell. The solid state impedance spectrum of the synthesized nanoparticles is similar to that of TiO 2. The prepared nanocomposite shows photoconductance revealing photogeneration of electron-hole pairs. The synthesized nanomaterial photocatalytically degrades dyes effectively.
Reaction Kinetics and Catalysis Letters, 2002
The oxidation of 14 para-, meta-, and ortho-substituted phenyl methyl sulfides with isonicotinium... more The oxidation of 14 para-, meta-, and ortho-substituted phenyl methyl sulfides with isonicotinium dichromate in acetonitrile, brought out by p-toluenesulfonic acid, follows a common mechanism, conforms to the isokinetic relationship but not to any of the linear free energy relationships; the isokinetic temperature lies in the experimental temperature range.
RSC Advances, 2015
The order of binding energy values for imidazole adsorbed ZnO clusters through the preferred azom... more The order of binding energy values for imidazole adsorbed ZnO clusters through the preferred azomethine nitrogen site is imidazole–Zn4O4 (R) > imidazole–Zn3O3 > imidazole–Zn4O4 (W) > imidazole–Zn2O2.
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2015
ZnO nanoparticles were doped with Ce(3+) by sol-gel synthesis and characterized by high-resolutio... more ZnO nanoparticles were doped with Ce(3+) by sol-gel synthesis and characterized by high-resolution scanning electron microscopy (HR-SEM), powder X-ray diffraction (XRD) and UV-visible diffuse reflectance (DRS) and photoluminescence (PL) spectroscopies. The dynamics of photoinduced electron injection from styryl phenanthrimidazole to Ce(3+)-doped ZnO nanoparticles has been studied by absorption, fluorescence and lifetime spectroscopic methods. Both the absorption and fluorescence quenching results suggest association between Ce(3+)-doped ZnO and the phenanthrimidazole. The free energy change (ΔGet) for electron injection has been calculated. The critical energy transfer distance between the phenanthrimidazole and Ce(3+)-doped ZnO nanoparticles has been deduced. In contrast to our earlier observation of enhancement of fluorescence of the phenanthrimidazole by ZnO nanoparticles, doping ZnO with Ce(3+) turns off its fluorescence. These findings provide a method to test the presence of Ce(3+) in ZnO nanocrystals.
Sensors and Actuators B …, 2012
A new kind of imidazole derivative, 4, 5-diphenyl-2 (E)-styryl-1H-imidazole, has been synthesized... more A new kind of imidazole derivative, 4, 5-diphenyl-2 (E)-styryl-1H-imidazole, has been synthesized. UV–vis absorption and fluorescence spectral studies show the interaction of the imidazole derivative with anatase and rutile phases of nanocrystalline TiO2. Anatase ...
Key Engineering Materials, 2013
CuO nanoleaves have been synthesized by cetyl trimethyl ammonium bromide (CTAB)-assisted microwav... more CuO nanoleaves have been synthesized by cetyl trimethyl ammonium bromide (CTAB)-assisted microwave method and characterized by powder X-ray and selected area electron diffractions, scanning and transmission electron microscopies and energy dispersive X-ray and electrochemical impedance spectroscopies. The CuO nanoleaves on graphite nonenzymatically sense glucose electrochemically. Cyclic voltammetic and chronoamperometric studies reveal the excellent catalytic activity of the modified electrode towards direct glucose oxidation. A wider linear range of glucose concentration and a shorter response time are observed. The detection limit of glucose is as low as 4µM and the CuO nanoleaves can be used as efficient electrochemical sensor.
Transition Metal Chemistry, 1995
... Chockalingam Karunakaran* and Balakrishnan Muthukumaran Department of Chemistry, Annamalai Un... more ... Chockalingam Karunakaran* and Balakrishnan Muthukumaran Department of Chemistry, Annamalai University, Annamalainagar 608 002, India ... was computed by a least-squares regression analysis of ln(A~-A) and time data, where A and A~ are the absorbance at time t and ...
Tetrahedron, 1991
The perbomte oxidation of organic sulphides to su@hoxides is j?rst order in perbomte. It b first ... more The perbomte oxidation of organic sulphides to su@hoxides is j?rst order in perbomte. It b first order with respect to diethyl and diphenyl sulphides, and the mte increases linearly with [MeSPh]. In high& acidic medium the oxiaiztion exhibits j%st o&r &pendence on [acid]. The oxidation ir inhibited by NaCl and enhanced by increase in solvent polari& Metabomte has no injluence on the oxidation mtes. The mtes of oxidation by hydrogen perox&, and hy&ogen pemxide with metabomte are about two-third of the perbomte oxidation mtes. Electmn-releasing groups accelemte and electron-with&awing groups retard the oxidation. In the oxidation of ðyl sulphide attack of pmtonated
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Papers by Karunakaran Chockalingam