Spectroscopic studies products

The only example of xenon in a fractional oxidation state, +, is the bright emerald green paramagnetic dixenon cation, Xe [12185-20-5]. Mixtures of xenon and fluorine gases react spontaneously with tiquid antimony pentafluoride in the dark to form solutions of XeF+ Sb2 F, in which Xe is formed as an iatermediate product that is subsequently oxidized by fluorine to the XeF+ cation (83). Spectroscopic studies have shown that xenon is oxidized at room temperature by solutions of XeF+ ia SbF solvent to give the XE cation (84). 

In some reactions, the situation kj > 2 exists. Under these conditions, the eoncentration of the intermediate will build up as it goes on more slowly to product. The possibility of isolating, or at least observing, the intermediate then exists. If both kj and k2 are large, the reaction may proceed too rapidly to permit isolation of the intermediate but spectroscopic studies, for example, should reveal the existence of two distinct phases for the overall reaction. It should be possible to analyze such a system and determine the two rate constants. 

UV-visible spectroscopic studies of polymerization of Pu(IV) hydrolysis products. 233, 235-39... 

The nifU gene product (NifU) from A. vinelandii has been overexpressed in E. coli and the recombinant protein purified and characterized (60). NifU is a homodimer of 33-kDa subunits with 2 Fe atoms per subunit. Spectroscopic studies showed the presence of [Fe2S2l clusters with = 254 mV and only cysteinyl coordination, but with... 

Two methods were also used for the formation and IR spectroscopic study of the diiodocarbene. Only one band at 525 cm assigned to vj of the carbene has been found in the IR spectra of the reaction products of vacuum pyrolysis of tetraiodomethane CI4 and its matrix reaction with atomic lithium. 

An IR spectroscopic study of the radicals CF3, C2F5, C3F7 and i-C3F7 has been carried out. These radicals were formed as products of vacuum pyrolysis in a platinum reactor of the respective fluorinated iodoalkanes and were stabilized in argon matrices at 10-12 K (Snelson, 1970b Butler and Snelson, 1980a,b,c) as shown in (6). 

Wiberg et have performed the reaction in the presence of C-labelled cyanide ion and find no incorporation of activity into product ferrocyanide. Evidently the reversible ligand displacement proposed by the Czech workers does not take place and the electron-transfer scheme of Swinehart is preferable. Recent spectroscopic studies indicate that a complex [Fe(CN)5(CNS03)] functions as an intermediate in this reaction. 

The catalyst prepared above was characterized by X-ray diffraction, X-ray photoelectron and Mdssbauer spectroscopic studies. The catalytic activities were evaluated under atmospheric pressure using a conventional gas-flow system with a fixed-bed quartz reactor. The details of the reaction procedure were described elsewhere [13]. The reaction products were analyzed by an on-line gas chromatography. The mass balances for oxygen and carbon beb een the reactants and the products were checked and both were better than 95%. 

Ito and co-workers observed the formation of zinc bound alkyl carbonates on reaction of carbon dioxide with tetraaza macrocycle zinc complexes in alcohol solvents.456 This reversible reaction was studied by NMR and IR, and proceeds by initial attack of a metal-bound alkoxide species. The metal-bound alkyl carbonate species can be converted into dialkyl carbonate. Spectroscopic studies suggested that some complexes showed monodentate alkyl carbonates, and varying the macrocycle gave a bidentate or bridging carbonate. Darensbourg isolated arylcarbonate compounds from zinc alkoxides as a by-product from work on polycarbonate formation catalysis.343... 

J. Schmidt and S. Huneck, Mass spectroscopy of natural products. V. Mass spectroscopic studies of ring A substituted allobetulane derivatives, Org. Mass Spectrom., 14, 646 655 (1979). 

Laser spectroscopic study of the reaction of FL with alcohols in either acetonitrile or hydrocarbon solution appears to show that 3FL is consumed rapidly by the alcohol the absorptions associated with 3FL decay faster in the presence of alcohol than in its absence. However, the product of this reaction is the ether expected from the singlet carbene (Table 7). Moreover,... 

Sealants obtained by curing polysulfide liquid polymers with aryl bis(nitrile oxides) possess stmctural feature of thiohydroximic acid ester. These materials exhibit poor thermal stability when heated at 60°C they soften within days and liquefy in 3 weeks. Products obtained with excess nitrile oxide degrade faster than those produced with equimolar amounts of reagents. Spectroscopic studies demonstrate that, after an initial rapid addition between nitrile oxide and thiol, a second slower reaction occurs which consumes additional nitrile oxide. Thiohydroximic acid derivatives have been shown to react with nitrile oxides at ambient temperature to form 1,2,4-oxadiazole 4-oxides and alkyl thiol. In the case of a polysulfide sealant, the rupture of a C-S bond to form the thiol involves cleavage of the polymer backbone. Continuation of the process leads to degradation of the sealant. These observations have been supported by thermal analysis studies on the poly sulfide sealants and model polymers (511). 

VO(acac)2 < VO(Et-acac)2 VO(Me-acac)2 BMOV. Conversion rates for all hydrolysis products were faster than for the original species. Both EPR and visible spectroscopic studies of solutions prepared for administration to diabetic rats ocumented both a salt effect on the species formed and formation of a new halogen-containing complex. The authors concluded that vanadium compound efficacy with respect to long-term lowering of plasma glucose levels in diabetic rats traced the concentration of the hydrolysis product in the administration solution. 

Hayashi et al. proposed a catalytic cycle for the rhodium-catalyzed 1,4-addition of phenylboronic acid to 2-cyclo-hexenone (Scheme 28), which was confirmed by NMR spectroscopic studies.96 The reaction presumably involved three intermediates, phenylrhodium a, oxa-7r-allylrhodium b, and hydroxorhodium c complexes. Complex a reacted with 2-cyclohexenone to give b by insertion of the carbon-carbon double bond of enone into the phenyl-rhodium bond followed by isomerization into the thermodynamically more stable complex. Complex b was converted to c upon addition of water, liberating the phenylation product. Transmetallation of the phenyl group from phenylboronic acid to rhodium took place in the presence of triphenylphosphine to regenerate a. 

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