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41.
Gunasekaran Raja Ray J. Butcher Chinnasamy Jayabalakrishnan 《Transition Metal Chemistry》2012,37(2):169-174
A Schiff base (HL) has been synthesized and characterized by physico-chemical, spectroscopic and X-ray crystallography studies.
Three of its Ru(III) complexes were synthesized and characterized by analytical and spectroscopic studies. The DNA binding
properties of HL and its Ru(III) complexes have been investigated by electronic absorption spectroscopy. Also, HL and its
Ru(III) complex [RuCl2(AsPh3)L] were tested for DNA cleavage properties. The results showed that the complex cleaves DNA more rapidly than the free ligand.
Further, an in vitro study of the cytotoxicity of HL and the complex [RuCl2(AsPh3)L] was carried out. 相似文献
42.
Nagarajan Sathya Arumugam Manimaran Gunasekaran Raja Periyasamy Muthusamy Kandasamy Deivasigamani Chinnasamy Jayabalakrishnan 《Transition Metal Chemistry》2009,34(1):7-13
New mononuclear ruthenium(III) Schiff base complexes of the type [RuX2(EPh3)(L)] (X = Cl or Br; E = P or As; L = monobasic tridentate Schiff base derived from o-aminophenol or o-aminothiophenol with ethylacetoacetate or ethylbenzoylacetate) have been synthesized. The Schiff base ligands chelate to ruthenium
through O, N, and O/S by dissociation of the phenolic proton/thiophenolic proton forming chelate rings. These complexes have
been characterized by physico-chemical and spectroscopic methods. Cyclic voltammetric data of all the complexes showed Ru(III)/Ru(IV)
oxidation and Ru(III)/Ru(II) reduction within the range of 0–1.5 V and 0 to −1.5 V with respect to Ag/AgCl, respectively.
The complexes were tested as catalysts in the oxidation of alcohols using molecular oxygen at ambient temperature, and also
in C–C coupling reactions.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
43.
To date, biosynthesis of metal nanoparticles has been intensively studied using bacteria and fungi. We have isolated and identified metal resistant bacterial strains from electroplating industries, they produce silver nanoparticles. The reduction reaction of aqueous silver nitrate with bacterial biomass was carried out for 120 h. Bacteria produced metallic nanoparticles showed a strong absorbance at surface plasmon resonance wavelength around 420 nm. The size and morphology of these nanoparticles were typically imaged using high resolution transmission electron microscopy, the particles size ranges between 4 and 5 nm and are spherical in shape. The crystal structure of the particles was characterized by X-ray diffraction pattern. The full width half maxima from X-ray diffraction measurements indicated that the particles exhibited face-centered cubic phase. 相似文献
44.
A normal coordinate analysis on chlorambucil and thioguanine has been carried out with a set of symmetry coordinates following
Wilson’s F-G matrix method. The potential constants evaluated for these molecules are found to be in good agreement with literature values
thereby confirming the vibrational assignments. To check whether the chosen set of vibrational frequencies contribute maximum
to the potential energy associated with the normal coordinates of the molecule, the potential energy distribution has been
evaluated.
相似文献
45.
Ashokkumar B Senthilkumar SR Gunasekaran P 《Applied biochemistry and biotechnology》2004,118(1-3):89-96
Aspergillus niger NRRL330 produces extracellular β-fructofuranosidase (Ffase), and its production is subject to repression by hexoses in the
medium. After ultraviolet mutagenization and selection, seven derepressed mutants resistant to 2-deoxyglucose (2-DG) were
isolated on Czapek’s minimal medium containing glycerol. One of the mutants, designated DGRA-1, produced higher levels of
Ffase. A considerable difference occurred in the mutants with reference to hexokinase and intracellular acid phosphatase activities.
The hexokinase activity of the mutant DGRA-1 (0.69 U/mg) was 1.8-fold higher than the wild type (0.38U/mg). Intracellular
acid phosphatase activity of the mutant DGRA-1 (0.83 U/g of mycelia) was twofold higher than that of the wild type (0.42U/g
of mycelia), suggesting that phosphorylation and dephosphorylation steps could attribute to the 2-DG resistance of A. niger. However, additional mutations could account for the increased production of Ffase in the mutant DGRA-1. 相似文献
46.
47.
Gunasekaran S Anbalagan G 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,69(2):383-390
Limestone and dolomite minerals have been investigated by EPR and optical absorption studies. The optical absorption results indicate the presence of ferrous and ferric ion in both the minerals. The bands observed at 24,750, 22,780, 19,415 and 14,450cm(-1) are assigned to 6A1-->4T2 (4D), 6A1-->4E, 4A1 (4G), 6A1-->4T2 (4G) and 6A1-->4T1 (4G) d-d transitions of Fe3+ ions, respectively. A low energy band at 10,638cm(-1) is identified as being due to Fe2+ ion and can be attributed to 5T2g-->5E(g) transition. The weak band in the region 30,000-40,000cm(-1) corresponds to Fe-O charge transfer. Crystal field and Racah parameters evaluated for the Fe2+ ion are Dq=990cm(-1), B=885cm(-1) and C=3860cm(-1) and that for Fe3+ ions are Dq=1040cm(-1), B=703cm(-1) and C=3150cm(-1). The room temperature 9 and 35GHz EPR spectra of the minerals exhibit a sextet hyperfine pattern characteristic of Mn2+. The EPR parameters obtained for Mn2+ in limestone are g=2.00399, A= -9.411mT, D= -8.19mT and these values confirm that the Mn2+ ion are located in the calcite impurity. For Mn2+ in dolomite are g=2.0004, A= -9.45mT for Mn2+ substituted in the Ca lattice site and g=2.00984, A= -9.37mT, D= -9.94mT for substitution at the Mg site. The EPR spectra of heat-treated limestone and dolomite samples at 950 degrees C show a signal corresponding to CO2(-) ion. 相似文献
48.
Gunasekaran S Seshadri S Muthu S Kumaresan S Arunbalaji R 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(3):550-556
The FTIR and FT Raman spectra of p-anisaldehyde has been recorded in the regions 4,000-400 and 3,500-100 cm(-1), respectively. The optimized geometry, frequency and intensity of the vibrational bands of p-anisaldehyde were obtained by ab initio and DFT levels of theory with complete relaxation in the potential energy surface using 6-31G(d,p) basis set. A complete vibrational assignment aided by the theoretical harmonic frequency analysis has been proposed. The harmonic vibrational frequencies calculated have been compared with experimental FTIR and FT Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically constructed bar type spectrograms. 相似文献
49.
Maruthachalam Mohanraj Ganesan Ayyannan Gunasekaran Raja 《Journal of Coordination Chemistry》2016,69(23):3545-3559
The synthesis, spectral characterization, and biological studies of ruthenium(II) hydrazone complexes [RuCl(CO)(PPh3)2L] (where L = hydrazone ligands) have been carried out. The hydrazones are monobasic bidentate ligands with O and N as the donors and are preferably found in the enol form in all the complexes. The molecular structure of the ligands HL1, HL2, and HL3 were determined by single-crystal X-ray diffraction. The DNA binding studies of the ligands and complexes were carried out by absorption spectroscopic and viscosity measurements. The results revealed that the ligands and complexes bind to DNA via intercalation. The DNA cleavage activity of the complexes, evaluated by gel electrophoresis assay, revealed that the complexes are good DNA cleaving agents. The antioxidant properties of the complexes were evaluated against DPPH, OH, and NO radicals, which showed that the complexes have strong radical-scavenging. Further, the in vitro cytotoxic effect of the complexes examined on HeLa and MCF-7 cancer cell lines showed that the complexes exhibited significant anticancer activity. 相似文献
50.
Enhancement of TbIII–CuII Single‐Molecule Magnet Performance through Structural Modification
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María José Heras Ojea Dr. Victoria A. Milway Dr. Gunasekaran Velmurugan Dr. Lynne H. Thomas Dr. Simon J. Coles Dr. Claire Wilson Dr. Wolfgang Wernsdorfer Prof. Gopalan Rajaraman Dr. Mark Murrie 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(36):12839-12848
We report a series of 3d–4f complexes {Ln2Cu3(H3L)2Xn} (X=OAc?, Ln=Gd, Tb or X=NO3?, Ln=Gd, Tb, Dy, Ho, Er) using the 2,2′‐(propane‐1,3‐diyldiimino)bis[2‐(hydroxylmethyl)propane‐1,3‐diol] (H6L) pro‐ligand. All complexes, except that in which Ln=Gd, show slow magnetic relaxation in zero applied dc field. A remarkable improvement of the energy barrier to reorientation of the magnetisation in the {Tb2Cu3(H3L)2Xn} complexes is seen by changing the auxiliary ligands (X=OAc? for NO3?). This leads to the largest reported relaxation barrier in zero applied dc field for a Tb/Cu‐based single‐molecule magnet. Ab initio CASSCF calculations performed on mononuclear TbIII models are employed to understand the increase in energy barrier and the calculations suggest that the difference stems from a change in the TbIII coordination environment (C4v versus Cs). 相似文献