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31.
The reduction of triphenyltin piperidyl dithiocarbamate in acetone has been investigated using d.c. polarography and cyclic
voltammetry. Polarographic reduction yielded four well-defined waves, two of which were diffusion-controlled and two of which
appear to represent adsorption processes. The cyclic voltammetric study yielded results in close agreement with the polarographic
data. Results appear to indicate the release of the dithiocarbamate moiety, followed by reduction to form the triphenyltin
radical, which undergoes dimerization, as well as reduction to the triphenyltin anion. For comparison, the polarographic reduction
of triphenyltinchloride was investigated. A mechanism similar to that proposed by earlier authors for the polarographic behaviour
of tributyltin oxide was found.
For convenience, the more commonly used terminology of piperidyl dithiocarbamate is used throughout the paper, in place of
(piperidine-1-carbodithioato) triphenyltin (IV). 相似文献
32.
X. Devaux A. C. Vajpei A. Rousset A. Rocher M. Brieu Uma Kailash Chandra I. P. Saraswat 《Journal of Thermal Analysis and Calorimetry》1990,36(2):529-543
DSC measurements in air from 20 to 800° are reported on aged iron(III)-chromium(III) coprecipitated hydroxides (with Fe3+Cr3+ wt% ratios of 91, 73, 11, 37 and 19). A comparison of the DSC profiles of aged coprecipitates with the thermal behaviour of freshly precipitated and well characterized samples provided information on the modification occurring in the structure and reactivity of the coprecipitates on prolonged aging.
Dedicated to Professor Wahid U. Malik, Founder-President, Indian Council of Chemists, India, with profound regards and fond memories of his youthful enthusiasm and ceaseless and pioneering efforts towards the development of chemical education and research activities at the University of Roorkee, Roorkee, India, on the occasion of his 70th birthday.
Paper presented at the World Conference on Thermal Analysis, Capri (Italy), 1989.
We thank Professor J. Pescia, Dr.G. Ablart and N. Favillier of Laboratoire de Magnétisme et d'Electronique Quantique for their interest in this work. A. C. Vajpei expresses his gratefulness to C.N.R.S. and C.N.O.U.S., Paris, for financial support of this work. 相似文献
Zusammenfassung Es werden DSC-Messungen an gealterten kogefällten Eisen(III)Chrom(III)-hydroxiden (mit Fe3+Cr3+ Gewichtsanteilen von 91, 73, 11, 37 und 19) im Temperaturbereich von 20 bis 800° beschrieben. Ein Vergleich der DSC-Profile von gealterten Kofällungen mit dem thermischen Verhalten frisch gefällter und gut definierbarer Proben lieferte Informationen über die Veränderungen in Struktur und Reaktivität der Koniederschläge bei längerem Altern.
Dedicated to Professor Wahid U. Malik, Founder-President, Indian Council of Chemists, India, with profound regards and fond memories of his youthful enthusiasm and ceaseless and pioneering efforts towards the development of chemical education and research activities at the University of Roorkee, Roorkee, India, on the occasion of his 70th birthday.
Paper presented at the World Conference on Thermal Analysis, Capri (Italy), 1989.
We thank Professor J. Pescia, Dr.G. Ablart and N. Favillier of Laboratoire de Magnétisme et d'Electronique Quantique for their interest in this work. A. C. Vajpei expresses his gratefulness to C.N.R.S. and C.N.O.U.S., Paris, for financial support of this work. 相似文献
33.
Kamlakar Avasthi Diwan S. Rawat Tilak Chandra Ashoke Sharon Prakas R. Maulik 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(6):o311-o313
In 5-benzyl-1,7-dimethyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-d]pyrimidine-4,6-dione, C14H14N4O2, which crystallizes in space group P, weak intermolecular C—H⋯O hydrogen bonds generate dimers. The isomeric compound 1-benzyl-5,7-dimethyl-4,5,6,7-tetrahydro-1H-pyrazolo[3,4-d]pyrimidine-4,6-dione, C14H14N4O2, crystallizes in space group P21/n, and shows no such dimerization. Instead, it exhibits C—H⋯π interactions with the phenyl ring. In both structures, the molecules are linked by aromatic π–π-stacking interactions. 相似文献
34.
We have carried out a series of molecular-dynamics simulations of water-methanol mixtures containing either an ionic or a neutral atomic solute to investigate the effects of composition of the mixture on the diffusion of these solutes. Altogether, we have considered 17 different systems of varying composition ranging from pure water to pure methanol. The diffusion coefficients of ionic solutes are found to show nonideal behavior with variation of composition of the solvent mixture. The extent of nonideality of the solute diffusion is found to be similar to the nonideality that is observed for the diffusion and orientational relaxation of water and methanol molecules in these mixtures and is attributed to the enhanced stability of the hydrogen bonds and formation of interspecies complexes in the mixtures. The neutral solute shows characteristics of hydrophobic solvation and its diffusion decreases monotonically with increase of methanol concentration. The present simulation results are compared with those of experiments wherever available. 相似文献
35.
Ghosh SK Khatua PK Ghosh JK Bhattacharya SC 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,61(3):395-401
This paper has explored the quenching of fluorescence of the dye safranine T (ST) by the inorganic cations viz Cu2+, Co2+, Ni2+ and Mn2+ in micellar solutions of the surfactant dioxyethylene nonyl phenol (Igepal CO-210), pentaoxyethylene nonyl phenol (Igepal CO-520) and dodecaoxyethylene nonyl phenol (Igepal CO-720). The quenching results have been calculated in light of stern volmer equation (SV) to evaluate the extent of interaction between the fluorophore (ST) and quencher. The average concentration of the quencher ions in the micelle have been determined. The quenching efficiency of ST by inorganic ions in micellar medium is lower than that in aqueous medium. The results show that the ions get partitioned in the micellar medium. The values of the partition coefficient of the ions decrease with increase in HLB value and number of oxyethylene groups in Igepal. 相似文献
36.
Mohandas Devaki V. Whelan Douglas R. Panchal Chandra J. 《Applied biochemistry and biotechnology》1995,(1):307-318
Mutants resistant to comparatively high levels of acetic acid were isolated from the xylose-fermenting yeastsCandida shehatae andPichia stipitis by adapting these cultures to increasing concentrations of acetic acid grown in shake-flask cultures. These mutants were
tested for their ability to ferment xylose in presence of high acetic acid concentrations, in acid hydrolysates of wood, and
in hardwood spent sulfite liquor, and compared with their wild-type counterparts and between themselves. TheP. stipitis mutant exhibited faster fermentation times, better tolerance to acid hydrolysates, and tolerance to lower pH. 相似文献
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