摘要:

Ionisation constants of some pyrazolidine-3,5-dione derivatives were measured in ethanol by potentiometric and spectrophotometric methods. The electroactivity of these compounds is in relation to the enolic and diketonic equilibrium in this medium.

ISSN:0008-4042    

DOI:10.1139/v81-109

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The nature of the products obtained from the reaction of chelocardin (1) and the model compound 2-acetyldimedone (5) with a variety of amines was investigated. It was observed that amines react with β-triketones having an exocyclic carbonyl side-chain to give exclusively β,β′-diketoenamines with substitution at the side-chain carbonyl.

ISSN:0008-4042    

DOI:10.1139/v81-110

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The solubility of water in liquid vinyl chloride has been measured over the temperature range −17° to 60 °C by a classical water absorption method. Solubility equations for water in vinyl chloride have been derived and the standard thermodynamic function changes for water transfer have been evaluated.

ISSN:0008-4042    

DOI:10.1139/v81-111

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

A complete solution of the strong-collision master equation for unimolecular reaction is derived, for any number of distinct reaction products. This solution provides exact results for any chemical activation process under the strong-collision assumption.

ISSN:0008-4042    

DOI:10.1139/v81-112

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Protoporphyrin IX dimethyl ester has been converted into the two 2,4-positional isomers bearing hydroxyethyl and methoxycarbonylvinyl side chains. The 4-(2-hydroxyethyl) group was extended to a methoxycarbonylethyl group to give the tetramethyl ester of porphyrin S-411 (2-methoxycarbonylvinyl-4-methoxycarbonylethyldeuteroporphyrin dimethyl ester). On the other hand reduction of the 4-methoxycarbonylvinyl to the corresponding methoxycarbonylethyl group and dehydration of the 2-(2-hydroxyethyl) to a vinyl side chain gave the trimethyl ester of harderoporphyrin (2-vinyl-4-methoxycarbonylethyldeuteroporphyrin dimethyl ester).

ISSN:0008-4042    

DOI:10.1139/v81-113

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

HClO4salts ofN,N′-tetramethylalkanes (compounds1–6) and ofN,N′-tetraalkyl-o-xylildiamines (compounds7–11) and HAuCl4salts ofN,N′-tetramethyl-o-xylildiamine-di-N-oxide (compound12) and ofo-xylildipiperidyl-di-N-oxides (compounds13–14) were studied by nmr and ir spectroscopy. It is shown that in the compounds3,4,5, and7–11, long intramolecularhydrogen bonds with large proton polarizability and in compounds12–14, short intramolecularhydrogen bonds with large proton polarizability are formed. The study of the compounds1–6shows that the most favorable conditions for the formation of the intramolecular easily polarizable hydrogen bonds occur with compound4, i.e., if these hydrogen bonds are present in the 7-membered rings. In the case of compounds7–14it is shown that the continua usually observed with easily polarizable hydrogen bonds vanish when these bonds become screened from their solvent environments. Then, instead of continua only bands of the fundamental transitions are observed, with the longbonds in the region 2800–1800 cm−1and with the shortbonds in the region 1200–850 cm−1. This result demonstrates that for the occurrence of the ir continua, the interaction of the easily polarizable hydrogen bonds with their solvent environments is absolutely necessary. Furthermore, it is shown with the long as well as the short hydrogen bonds that the intensity of the continua decreases strongly with deuteration, demonstrating that in both cases the deuteron polarizabilities are much smaller than the proton polarizabilities of the hydrogen or deuterium bonds, respectively. From this observation it is concluded that the proton potentials of these structurally symmetrical hydrogen bonds are considerably deformed by their molecular surroundings.

ISSN:0008-4042    

DOI:10.1139/v81-114

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The interactions ofN-picrylethylenediamine as the HCl salt (PED) with methoxide ion in dimethyl sulfoxide – methanol (DMSO/MeOH) media and with 1,4-diazabicyclooctane in dimethyl sulfoxide have been investigated spectrophotometrically at 25.0 °C. Evidence is presented to show that, in solvent mixtures rich in dimethyl sulfoxide (e.g. 95/5, V/V, DMSO/MeOH), deprotonation reactions at the nitrogen centres on the ethylenediamine occur in preference to reactions in which σ-complexes are formed via addition of CH3O−to one or more ring carbon atoms. The initial 1:1 interaction of CH3O−and PED results in the rapid, reversible deprotonation of the NH centre while the 2:1 interaction is associated with rapid, reversible abstraction of H+from the NH3+centre. At mole ratios of CH3O−to PED > 3 a σ-complex is formed as a result of the addition of CH3O−ion to a C-3 ring carbon atom of the di-deprotonated PED. The uv–visible absorption properties of these various species are reported and compared to the properties of corresponding species formed in related systems.

ISSN:0008-4042    

DOI:10.1139/v81-115

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Acylation of (cyclopropylmethyl)trimethylsilane using RCOCl/AlCl3(R: saturated hydrocarbon group) constitutes a mild, convenient route to β,γ-unsaturated ketones free from the conjugated isomers. With α,β-unsaturated acyl chlorides a competitive reaction between the C—H and C—Si allylic cleavage is observed whereas chloroacetyl chloride affords the γ,δ-ethylenic corresponding ketone. A mechanism involving the catalytic role of HCl in the formation of β,γ-unsaturated and chloroketones is proposed.

ISSN:0008-4042    

DOI:10.1139/v81-116

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

The recent critical evaluation of Linnett Double Quartet theory by Langler, Trenholm, and Wasson is critically examined and found to be based on misrepresentations of the theory's basic postulates and its use in predicting chemical reactivity. Various ways in which Linnett's original work can be profitably extended are suggested and briefly discussed.

ISSN:0008-4042    

DOI:10.1139/v81-117

出版商:NRC Research Press    

年代:1981

数据来源: NRC

摘要:

Abinitiomolecular orbital calculations are reported for SF4(bothC2vandC4vsymmetries), SOF2, and SO2F2. Geometry searches were conducted using the STO-3G* basis set; the energies were recalculated at the predicted equilibrium structures also using STO-3G and 44-31G, and the latter basis set with the addition of five realdGaussian orbitals on the sulfur atom. The predicted geometries agree well with experiment, although S=O bonds are consistently predicted too long by ∼0.03 Å, and the variation in S—F bond lengths among different environments is underestimated. The energy stabilization associated with the addition ofdorbitals is generally consistent with our previous calculations, i.e. it is a constant amount per bond in hypervalent sulfur compounds in extended basis calculations. Replacement of F by OH is predicted to be more exothermic in SO2F2than in SOF2, and the relevance of this prediction to estimated heats of formation for SOF2and SO(OH)2is discussed.

ISSN:0008-4042    

DOI:10.1139/v81-118

出版商:NRC Research Press    

年代:1981

数据来源: NRC