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911.
V.G. Krishnan 《Journal of Molecular Structure》1978,50(1):99-102
ESR studies have been made on the single crystals of tri(octamethylpyrophosphoramide)-magnesium perchlorate doped with the paramagnetic vanadyl ion at 295 and 77 K. The spectra are characterized by a parallel and perpendicular set of hyperfine lines usually seen for the vanadyl ion. The lowering of the g value and increasing of the A value has been attributed to the extremely ionic metal—ligand bonding. 相似文献
912.
913.
K. K. H. Koh L. D. Vela R. E. Jervis S. S. Krishnan 《Journal of Radioanalytical and Nuclear Chemistry》1994,180(1):49-54
The effect of neutron irradiation on the leachability of elements in solid wastes comprising of coal fly ash, hospital and municipal incinerator ashes was studied. There was a marked increase in leachability in the neutron irradiated wastes compared to non-irradiated wastes especially for elements such as As, Cd, Co, Cr, Sm and Zn. For elements such as Fe and Sm there was no significant difference in the leachabilities in the irradiated and non-irradiated wastes. The possible causes of this scenario and implications are discussed. 相似文献
914.
Recent progress on material designs merged with nanotechnology and biotechnology strategies has advanced studies of complex biological samples on electrodes for cytochrome P450 (CYP)–driven biocatalytic reactions (e.g. liver membrane fractions, cells, and various organ-specific CYP extracts). In addition, protein engineering of CYP enzymes with their reductase partner in membranes (e.g. baculovirus- or Escherichia coli bacteria–expressed CYP microsomes) and other recombinant strategies (e.g. engineered CYP and reductase fusion domains and site-directed CYP mutagenesis) are promising sustainable approaches for offering abundant sources of CYP enzymes for electrocatalytic applications. The combination of in silico and experimental electroanalytical methods with hyphenated approaches and biological assays can offer early and rigorous profiling of new drugs and specialty chemicals for safe exposure and beneficial use. 相似文献
915.
Tushar Kanti Chakraborty Rajarshi Samanta Krishnan Ravikumar 《Tetrahedron letters》2007,48(36):6389-6392
Radical-mediated opening of chiral 2,3-epoxy alcohols, containing suitably positioned β-(alkoxy)acrylate moieties, using Cp2TiCl triggered intramolecular cyclization to give tetrahydrofuran and tetrahydropyran moieties. 相似文献
916.
Gilles Klopman Krishnan Namboodiri Melvin Schochet 《Journal of computational chemistry》1985,6(1):28-38
The values of log10 P (partition coefficient, in octanol/water) were calculated for about 200 organic molecules of diverse structures and functionalities. The method involves a simple procedure and appears accurate enough for semiquantitative applications. Further, this method of calculating log10 P values was shown to be successful in providing a better quantitative structure activity relationship (QSAR ) than the Hansch-type approach in the study of inhibitory activity of substituted phenols on Bacillus Subtilis spore germination. 相似文献
917.
K. P. Krishnan Namboodiri S. Viswanathan R. Ganesan V. C. Jyothi Bhasu 《Journal of computational chemistry》1981,2(4):392-401
The all-valence-electron CNDO /2 calculations were performed for the three isomeric nitrophenols. Using the newly derived σ-core charges and subsequently revising the valence-state ionization potentials and one-center two-electron repulsion integrals, Pariser–Parr–Pople (PPP ) CI calculations were performed on the title compounds following the Nishimoto–Forster scheme. A better agreement between theory and experiment has been observed in spectral assignments compared to the conventional PPP approach. Information from the CNDO /2 calculations was used to obtain useful electronic structural parameters and to get a quantitative insight into the chemical reactivity of these molecules. All the results were compared with the basic compounds, phenol and nitrobenzene. The electronic spectra of these isomers were recorded in both polar and nonpolar solvents. 相似文献
918.
An all-atom force field for 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) is presented. The classical intermolecular interaction potential for TATB is based on single-point energies determined from high-level ab initio calculations of TATB dimers. The newly developed potential function is used to examine bulk crystalline TATB via molecular dynamics simulations. The isobaric thermal expansion and isothermal compression under hydrostatic pressures obtained from the molecular dynamics simulations are in good agreement with experiment. The calculated volume-temperature expansion is almost one dimensional along the c crystallographic axis, whereas under compression, all three unit cell axes participate, albeit unequally. 相似文献
919.
Krishnan Ravikumar Balasubramanian Sridhar 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(8):o478-o482
Moxifloxacin, a novel fluoroquinolone with a broad spectrum of antibacterial activity, is available as the solvated monohydrochloride salt 7‐[(S,S)‐2‐aza‐8‐azoniabicyclo[4.3.0]non‐8‐yl]‐1‐cyclopropyl‐6‐fluoro‐8‐methoxy‐4‐oxo‐1,4‐dihydroquinoline‐3‐carboxylic acid chloride–water–methanol (2/1/1), C21H25FN3O4+·Cl−·0.5H2O·0.5CH3OH. The asymmetric unit contains two cations, two chloride ions, a molecule of water and one methanol molecule. The two cations adopt conformations that differ by an almost 180° rotation with respect to the piperidinopyrrolidine side chain. The cyclopropyl ring and the methoxy group are not coplanar with the quinoline ring system. The carboxylic acid function, the protonated terminal piperidyl N atom, the water molecule, the chloride ion and the methanol molecule participate in O—H⋯O, O—H⋯Cl, N—H⋯O and N—H⋯Cl hydrogen bonding, linking the molecules into extended two‐dimensional networks. 相似文献
920.
James R. Rabinowitz Krishnan Namboodiri Harel Weinstein 《International journal of quantum chemistry》1986,29(6):1697-1704
Because it is useful to have the molecular electrostatic potential as an element in a complex scheme to assess the toxicity of large molecules, efficient and reliable methods are needed for the calculation and characterization of these potentials. A multicenter multipole expansion of the molecular electron charge density calculated with a limited Gaussian basis set is shown here to have only a finite number of nonzero terms from which the molecular electrostatic potential can be calculated. The discrete contributions to the electrostatic potentials from the terms of this expansion provide a physically meaningful decomposition of the potential and a means for its characterization. With pyrrole as an example, the electrostatic potential calculated from this finite expansion of the electron density is compared to that obtained from exact calculations from the same wave function. Good agreement is obtained at distances greater than 1.5 A from any atom in the molecule. In contrast, rearrangement of the terms into an expansion corresponding only to Mulliken atomic charges and dipoles yields a decomposition that produces electrostatic potentials which agree less well with the exact potential. This discrepancy is attributable to the neglect of terms due to higher moments. 相似文献