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981.
The preparation of η-C3H5V(CO)5 from allyl chloride and sodium hexacarbonylvanadate (–I) is reported. Composition, IR and NMR spectra are in accordance with a π-bonded C3H5-moiety; the preparation has been extended to give complexes with substituted allyl groups. Furthermore (1-3-η-2-butenyl)pentacarbonylvanadium can be obtained by the addition of butadiene to HV (CO)6. 相似文献
982.
The thermodynamic treatment of double-pseudobinary solutions of the type (A
xBy)
r
o(M
uNv)
s
o presented in a preceding publication was extended to include the conditions defining the critical points for the asymmetric case (r
os
o) and approximations for the spinodal and binodal surface near the critical solution point.Closed solutions for the coordinates of the critical points were obtained only for systems with ideal mixing behavior, and the isothermal binodal and spinodal near the critical solution point in such systems are adequately approximated by circles and ellipses, respectively. An axes ratio of
is nearly independent of the relative sublattice abundance and the major effect of changes in the ratios
o/r
o is a rotation of the binodal by an angle tg
.The principal features of nonideal regular systems for temperatures close to the critical solution point are described by expressions derived from small term expansions of the conditional equations, but generalizations are not possible to the same extent as for the case with ideal boundary systems. The results are discussed and the application of the equations demonstrated on model examples.Mit 6 Abbildungen 相似文献
983.
A carbon-rod atomizer (CRA) fitted with a 'mini-Massmann' carbon rod was evaluated for routine analysis of petroleum and petroleum products for trace metal content by atomic-absorption spectroscopy. Aspects investigated included sensitivity, detection limit, effect of solvent type, and interferences. The results of analysis of oil samples with this technique were compared with those obtained by other techniques. Metals studied were silver, copper, iron, nickel, and lead. Sensitivity and detection limit values obtained with the CRA were similar to those obtained with the carbon-filament atomizer. Strong 'solvent effects' were observed as well as interference by cations. On the basis of this study, design changes for the CRA are suggested, with the object of minimizing 'solvent effects' and interferences, increasing the atomization efficiency, and increasing the residence time of the atomic vapour in the optical path of the instrumental system. 相似文献
984.
Conjugated esters and amides react with aryldiazonium salts at room temperature (MeCN) to form the corresponding iminium hydrazone derivatives, which can be thermally cyclized to cinnoline-3-esters and cinnoline-3-amides. In general the intermediate iminium salts derived from the enamine amides cyclize faster than those from the enamine esters. Furthermore, the ease of cyclization depends upon the structure of the base-component of the enamine ester or the amide and the substituent in the aryl moiety of the diazonium salt. The configurational structure of the iminium hydrazones, studied by NMR spectroscopy, has been shown to involve H-bonding of the hydrazonyl N-H with the ester or the amide CO group. 相似文献
985.
Benzo[b] thiophene derivatives. XVIII. The sulfur isosteres of harmaline,harmine and related isomers
T. R. Bosin R. P. Maickel A. Dinner A. Snell E. Campaigne 《Journal of heterocyclic chemistry》1972,9(6):1265-1266
The sulfur analogs of harmaline, 7-methoxy-3,4-dihydro-1-methyl[1]benzothieno[2,3-c]-pyridine (Ib), harmine, 7-methoxy-1-methyl[1]benzothieno[2,3- c ]pyridine (IIb), and corresponding 6-methoxy isomers (Ic and IIc) have been synthesized for pharmacological evaluation as monoamine oxidase inhibitors. 相似文献
986.
The results of allowing tetrahydro-as-triazine-3(2H)-thiones to react with various α,β-diiunctional compounds, such as, α-bromoethyl p-toluenesulfonate, chloroacetaldehyde, α-bromophenylacet-uldehyde, phenaeyl bromide, chloroacetonitrile, α-bromophenylaeelonitrile, and α-cyanobenzyl p-toluenesulfonate are discussed. These condensations give either a 5H-thiazolo[3,2-b]-as-triazine or a 2H-thiazolo[2,3-c]-as-triazine. 相似文献
987.
Quantitative measurement of both bulk and localized oxygen concentrations is of importance in the study of oxidation kinetics.
We describe the combined application of two nuclear techniques, fast neutron activation analysis and (d, p) nuclear microprobe,
to the determination of oxygen concentrations and surface profiles for steam-oxidized Zircaloy-4 cladding specimens. Results
of measurements using these techniques are presented.
Work partially supported by Electric Power Research Institute Contract T.S.A. No. 20. 相似文献
988.
Quinolizidines containing an exocyclic double bond at C-2 (1,2) give on mild oxidation the amino dienes (3,4), as mixtures of geometric isomers with respect to the exocyclic double bond. The free enthalpy of activation for the rotation about the double bond has been estimated by NMR. 相似文献
989.
Oleg V. Mikhailov Marina A. Kazymova Tatyana A. Shumilova Galina A. Chmutova Svetlana E. Solovieva 《Transition Metal Chemistry》2005,30(3):299-304
The complexing process proceeding in the NiII–thiocarbohydrazide (H2N–H–NC(=S)–NH–NH2)–propanone triple system in EtOH solution and nickel(II)hexacyanoferrate(II) gelatin-immobilized matrix has been studied. It has been found that in the first case, template synthesis leading, as a minimum, to formation of three coordination compounds of NiII with (N,N,S,S)-donor tetradentate ligands having NiL1, NiL2 and NiL3compositions where L1 is 4,6,6-trimethyl-2,3,7,8-tetraazanonen-3-di(thiohydrazide)-1,9, L2 is 4,6,6,12-tetrametyl-1,9-dithio-2,3,7,8,10,11-hexaazatridekadien-3,11-hydrazide-1 and L3 is 2,8,10,10,16-pentamethyl-5,13-dithio-3,4,6,7,11,12,14,15-octaazaheptadekatrien-2,7,15 is observed, whereas in the gelatin-immobilized matrix, a complexing process in the system considered does not occur. 相似文献
990.
Zusammenfassung Der Vorgang der thermischen Umlagerung des 4-Hydroxy-5-acetyl-6-phenyl-pyrons-(2) (1) zum 4-Hydroxy-5-benzoyl-6-methyl-pyron-(2) (4) wird an Hand weiterer Beispiele studiert und ferner der Einfluß der Substituenten am C-5 bzw. C-6 des Lactonringes untersucht.
An investigation of more examples of the thermal rearrangement of 5-acetyl-4-hydroxy-6-phenyl-pyrone-(2) to 5-benzoyl-4-hydroxy-6-methyl-pyrone-(2) was carried out, it showed the influence of substituents at C-5 and C-6 of the lactone ring.相似文献