摘要:

N-Chloro-N-propyl-threo-6,7-dibromododecanamide, prepared by the successive bromination andN-chlorination ofN-propyl-(Z)-6-dodecenamide, was subjected to thermolytic homolysis in aqueous dioxane to yield a mixture of products from which, after zinc debromination, γ-6-(Z)-dodecenolactone was isolated. Some analogs of this lactone were similarly prepared.

ISSN:0008-4042    

DOI:10.1139/v76-021

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

A partial synthesis of methyl lambertianate from the 13-keto-degradation product1from methyl agathate is described. The furan ring is synthesized by the method of Burness, and involves hydroxymethyleneation of methyl ketone1, acetal formation, glycidic ester condensation, and final pyrolysis of the glycidic ester-acetal5to give methyl 16-carboxylambertianate. Methyl lambertianate was obtained in moderate yield by copper-quinoline decarboxylation.

ISSN:0008-4042    

DOI:10.1139/v76-022

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

A conformational study of 1,2,4-trithiolane and its tetramethyl derivative was carried out by vibrational and uv photoelectron spectroscopy (HeI). Analysis of the vibrational spectra shows the existence of a single form withC2orCssymmetry (half chair or envelope form). From the photoelectron data, we can conclude that the preferential form in the vapor phase is the half chair (C2).

ISSN:0008-4042    

DOI:10.1139/v76-023

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

A physical method for separation of alkali metals, carried out inside a surface ionization ion source of an electromagnetic isotope separator, was used to determine the isomeric ratio of84m,fRb produced in89Y targets bombarded by protons and α-particles of energies between 40 and approximately 160 MeV.The variation of isomeric ratio with energy of the incident particles enabled the principal reaction to be differentiated from other possible mechanisms. With compound nucleus formation as the mechanism and the use of a statistical Fermi-gas model, the spin cut-off parameters were deduced, based on the Huizenga–Vandenbosch formalism. The kinetic momentum effect was investigated by a comparison of the proton and α-particle induced reactions.

ISSN:0008-4042    

DOI:10.1139/v76-024

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

For gaseous UF6changes in the thermodynamic quantifies ΔG(= ΔA), ΔH(= ΔU), ΔCp(= ΔCv), and ΔSupon isotopic substitution can be determined by using the spectroscopically determined geometry and force field. The differences ΔGetc. are defined as (G238–Gx), where 238 andx(x = 235, 234, 233, and 232) are the masses of the central uranium atom. The changes in the thermodynamic quantities are related to the logarithm of the partition function ratio of the UF6species compared. The logarithm of the partition function ratio can be conveniently expressed as a series in temperature and hence, by using statistical mechanical relationships, the changes in thermodynamic quantities can be expressed as a series in temperature.Since these changes form examples of heavy isotope effects the validity and utility of the first quantum correction can be investigated. Uncertainties and trends in the magnitudes of the differences in the thermodynamic quantities due to uncertainties or changes in spectroscopic parameters are discussed by means of the first quantum correction. It has been found that the first quantum correction has little quantitative value in the lower temperature region, but it can be used in that range to explain some observed trends in the isotope effects. Some of the conclusions can also be applied to kinetic and equilibrium heavy isotope effects.

ISSN:0008-4042    

DOI:10.1139/v76-025

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

A wide range of arene complexes of the mercurous ion has been prepared from mercurous hexafluoroarsenate and the appropriate arene in liquid sulfur dioxide. Raman spectroscopy confirmed the integrity of the dimeric Hg22+cation in these complexes.13C nuclear magnetic resonance spectroscopy showed that Hg22+–arene complexes exist in sulfur dioxide solution. The13C data allowed the estimation of formation constants for the hexamethylbenzene,p-xylene, andp-dichlorobenzene complexes together with the13C chemical shifts for the bound substrates in these cases. The13C chemical shift changes (relative to the free substrate) on addition of Hg22+to SO2solutions of various methylated benzenes are compared with those occurring on complexation of the same arenes by the argentous ion and the Cr(CO)3moiety. In mercurous ion–arene complexes, it is concluded that the cation is involved in a localized interaction with the arene and that there are preferred binding sites. These sites may be identified by the complexation shifts for the Ag+– and Hg22+–arene complexes.

ISSN:0008-4042    

DOI:10.1139/v76-026

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The reactions of Hg2(AsF6)2with P(CF3)3, PF3, PCl3, P(CF3)Ph2, PClPh2, PPh3, P(OMe)3, AsPh3, SbPh3, SPPh3, SP(p-C6H4F)3, and SePPh3in liquid sulfur dioxide have been studied. The last five ligands form insoluble 1:1 complexes, Hg2(AsF6)2•L, if L:Hg22+ ≤ 1, but disproportionation of the mercurous ion occurs if L:Hg22+ > 1; the 1:1 mercurous complexes have been characterized by analysis and vibrational spectroscopy. There is no evidence for complexation of P(CF3)3. PPh3and P(OMe)3cause disproportionation of the mercurous ion under all conditions; Hg(PPh3)22+and Hg(P(OMe)3)22+have been characterized by13C and1H nmr respectively. When P(CF3)Ph2:Hg22+ ≤ 1 soluble Hg2(P(CF3)Ph2)2+is formed; the19F and13C nmr spectra of this complex are reported, as are those of Hg(P(CF3)Ph2)22+. In the system PF3–Hg2(AsF6)2–SO2no disproportionation occurs;19F nmr provides evidence that Hg2PF32+and, probably, Hg2(PF3)22+are formed.1J(P–F) in mercurous and silver(I) complexes of PF3is of unusually large magnitude. The13C nmr spectra of Hg(PPh3)22+, Hg2(P(CF3)PPh2)2+, and Hg(P(CF3)Ph2)22+, are consistent with the occurrence of little metal-to-phosphorus back-bonding in these phosphine complexes. The relationship between the net electron donating ability of a phosphine and the nature of its interaction with the mercurous ion is discussed.

ISSN:0008-4042    

DOI:10.1139/v76-027

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v76-029

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Reaction of tertiary alcohols with trichloroacetylisocyanate causes a marked downfield shift of the nmr signals of protons β to the hydroxyl group. This can be used to reveal the presence of methyl groups adjacent to a tertiary hydroxyl group and of other β protons which are sufficiently deshielded to be observed. This method has also been used to assign the geometry of the double bond of an allylic alcohol.

ISSN:0008-4042    

DOI:10.1139/v76-030

出版商:NRC Research Press    

年代:1976

数据来源: NRC