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111.
A. Manohar V. Venkatachalam K. Ramalingam S. Thirumaran G. Bocelli A. Cantoni 《Journal of chemical crystallography》1998,28(12):861-866
Synthesis, spectral, and single crystal X-ray structural studies on (2,2-bipyridyl)bis (dimethyldithiocarbamato)zinc(II) (1) and (l,10-phenanthroline)bis(dimethyldithiocarbamato)zinc(II) (2) complexes are reported in this paper. The complex (1) crystallizes in the orthorhombic lattice, space group Pcca, a = 18.456(3), b = 6.529(2), and c = 17.092(2) Å. The complex (2) crystallizes in the monoclinic space group C2/c, a = 13.372(2), b = 13.850(2), c = 24.680(3) Å, and = 102.71(4)°. IR spectra of the complexes (1) and (2) show the thioureide (C-N) bands at 1489 and 1510 cm–1, respectively, which are lower than the value observed for the parent bisdithiocarbamate. Reduction in the thioureide stretching frequency is due to the increase in coordination around the zinc ion and the resultant increase in electron density. Thermal studies indicate that the 1,10-phenanthroline adduct is marginally more stable than the other complex. X-ray crystal structures of the two adducts show them to be octahedrally coordinated and monomeric in nature. The Zn-S distances are longer than those observed in the parent bisdithiocarbamate. The thioureide C-N bond distances in (1) and in (2) indicate the partial double bond character. The most important structural changes as a result of the adduct formation are observed in the Zn-S bond distances and S-Zn-S bond angles, in terms of very significant increases in Zn-S bond distances and reductions in S-Zn-S angles, compared to the parent bisdithiocarbamate. The observed changes are indicative of a strong steric force in operation in the adducts rather than electronic effects. 相似文献
112.
Using the KKM mapping technique, we obtain existence results for the mixed equilibrium problem (under the relaxed \(\alpha \)-monotonicity assumption on the bi-function) in a reflexive Banach space. Several examples are given to show that our definition of \(\alpha \)-monotonicity and, hence, our results are more general than that in the existing literature. 相似文献
113.
Hanna Tialowska-Mocharla S. Manohar Gordon Atkinson 《Journal of solution chemistry》1992,21(6):545-555
Electromotive force measurements were carried out on the HCl–ZnCl2–H2O system at constant total ionic strengths of 0.1, 0.2, 0.5, 1.0 and 2.0 mol-kg–1 at 25 and 35°C using a cell consisting of Pt, H2(g, 1 atm)|HCl(mA), ZnCl2(mB)|AgCl/Ag. The data were interpreted by the mixed electrolyte equations of Pitzer and Kim in order to evaluate mixing ion-interaction parameters. The activity coefficients of ZnCl2 and the Gibbs excess free energies of mixing are calculated and presented at I=2.0 mol-kg–1 and compared with similar systems containing transition metal chlorides. 相似文献
114.
115.
An electromagnetically induced transparency (EIT) signal is observed in a V-type energy level scheme in a cesium vapor cell at room temperature. The effects of frequency detuning and the intensity of the pump laser on the EIT signal have been investigated. The performance of the probe-diode laser system, which is frequency stabilized on the EIT signal by using electrical feedback, is explored. The first derivative of the EIT signal offers a steeper slope and better S/N ratio for laser frequency stabilization than that of the Doppler-free hyperfine and crossover resonances. A comparative study of the frequency stability of an external-cavity diode laser stabilized at EIT and at the crossover resonance is presented. The square root of the Allan variance (σ) vs. integration time (τ) plot shows about a tenfold improvement in the frequency stability of the EIT-locked laser (σ ~ 2.043 × 10?13τ?1/2) over that of the crossover-locked laser under a short integration time (1–10 ms), whereas a twofold improvement is found under a long integration time (~1 s). 相似文献
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117.
The deep red diaquoperoxotitanium dipicolinate [TiO2(C7H3O4N) (H2O)2]2H2O crystallises in a pleochroic triclinic and a nonpleochroic orthorhombic modification. The structure of the former has been reported earlier. The structure of the latter, described in this paper, has been determined from X-ray diffractometer data and refined to R = 0.034. In both forms the complex occurs as the free acid, but the modes of packing are completely different. Bond lengths and angles agree closely. As in the other peroxotitanium(IV) chelate structures so far determined, titanium has an approximately pentagonal bipyramidal coordination with the peroxo group and the chelate ligand occupying equatorial sites and the waters forming the apices. The relationship proposed earlier between the basicity of the ligands and the bond lengths and colours of the related compounds is substantiated. The final difference Fourier maps obtained with normal and modified refinement procedures clearly reveal bonding electron densities. They indicate a pentagonal bipyramidal sp3d3 hybridisation of titanium with bent Ti-Operoxo bonds, again in agreement with the triclinic form and other peroxotitanium chelates. 相似文献
118.
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120.
M. C. Goromonzi S. K. Raman B. D. Padalia A. Manohar P. N. Koul 《Reaction Kinetics and Catalysis Letters》1980,15(1):131-136
The cause for a fall in the conversion of NH3 to NO within 73 hours from 97% to 78% with a cobalt oxide catalyst was investigated. Results show that sintering, change in valence and cation distribution in Co3O4 contribute to the decrease in activity. Incorporation of ThO2 and K2O improves the performance of the catalyst.
NH3 NO 73 97% 78%. , , Co3O4. ThO2 K2O NH3 NO.相似文献