摘要:

From a comparison of the dissociation energies of carbon–oxygen and carbon–sulfur bonds in alcohols, thioalcohols, ethers, and thioethers, a self-consistent set of values for the heats of formation of the methylthio-, ethylthio-,n-butylthio-,iso-butylthio-,sec-butylthio-,t-butylthio-, phenylthio-, and benzylthio-radicals is derived.

ISSN:0008-4042    

DOI:10.1139/v70-064

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

A study of complexes of (a) N,N-dimethyl,N′-diphenylphosphinohydrazine, DPH, viz., Pd(DPH)Cl2, Pd(DPH)2Cl2, [Pd(DPH)2Cl]ClO4, Pt(DPH)2Cl2, Pt(DPH)Cl4, Hg(DPH)Cl2; (b) N,N-dimethyl,N´-diphenylthiophosphinatohydrazine, DPS, viz., Pd(DPS)Cl2, Pt(DPS)Cl4, Ag(DPS)NO3, Zn(DPS)Cl2, Cd(DPS)Cl2, and Hg(DPS)Cl2, and (c) N,N-dimethylhydrazine, DMH, viz., Zn(DMH)2Cl2and Cd(DMH)Cl2, has been carried out using conductivity, molecular weight, infrared, and nuclear magnetic resonance measurements. DPH functions mostly as a unidentate ligand, with the phosphorus atom as the preferred donor site. Thus Pd(DPH)Cl2is a chlorobridged dimer in solution in weakly polar solvents, while the monomeric form in polar solvents is of uncertain structure. Atrans, four-coordinate structure is consistent for Pd(DPH)2Cl2. For [Pd(DPH)2Cl]ClO4, however, one DPH ligand is chelating through the phosphorus and terminal nitrogen atoms, while the second ligand is unidentate; the compound is a monomeric uni–univalent electrolyte in nitrobenzene. The ligand DPS appears to chelate via the sulfur and central nitrogen atoms, giving four-membered ring structures; acisconfiguration is suggested for Pd(DPS)Cl2. Zn(DMH)2Cl2is monomeric in solution, with the Me2N group coordinated to the metal.

ISSN:0008-4042    

DOI:10.1139/v70-065

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The crystal and molecular structure of sodium hydroxytrifluoborate, NaBF3OH, has been established by X-ray analysis. This compound crystallizes in the hexagonal system, space groupP63with cell parametersa = 8.084 Å andc = 7.958 Å. There are 6 molecules in the unit cell. Atomic parameters have been obtained from a block-diagonal least-squares refinement using anisotropic temperature parameters for boron and fluorine, and isotropic temperature parameters for sodium. The final agreement residual for 195 observed reflections isR = 0.090.The [BF3OH]−anions are distorted tetrahedra. It was not possible to distinguish between the positions of the fluorine atoms and the isoelectronic hydroxyl group.

ISSN:0008-4042    

DOI:10.1139/v70-066

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The Raman and infrared spectra of liquid and crystalline SiF4have been recorded. The assignment of some of the Raman bands of the crystal to longitudinal modes has been confirmed by the infrared reflection spectrum. These indicate that the crystal structure is not centrosymmetric. In other respects the spectra are also more complicated than is expected on the basis of the previously reportedTd3structure. Possible explanations are discussed.

ISSN:0008-4042    

DOI:10.1139/v70-067

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

In the radiolysis of oxygenated aqueous solutions of cysteine (RSH) at pH7, short chain reactions occur yielding cystine (RSSR) and hydrogen peroxide. Two competing reaction paths involving reaction of the thiyl radical (RS•) with oxygen or thiol anion (RS−) are postulated to explain the results.

ISSN:0008-4042    

DOI:10.1139/v70-068

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The sole product obtained from the reaction of indole-2-carboxylic acid and ethylN,N-dichlorocarbamate was 3,3,5-trichlorooxindole (7). In contrast, methyl indole-2-carboxylate gave a mixture of methyl-3,5-dichlorooxindole-3-carboxylate (10) and methyl-3,5,7-trichlorooxindole-3-carboxylate (11), the same products as obtained from the chlorination of methyl indole-3-carboxylate. The structures of these products were confirmed by degradation to known compounds and/or by synthesis, and mechanisms for their formation were suggested.

ISSN:0008-4042    

DOI:10.1139/v70-069

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Di-p-tolyl mercury crystallizes in space groupP21/cwith cell constantsa = 10.12,b = 5.07,c = 11.65 Å, β = 91.8°,Z = 2. The structure was solved by mercury-phased three-dimensional electron density Fourier synthesis and refined by least-squares. The finalR-index was 0.085 for all reflections. The molecule of di-p-tolyl mercury is found to be planar having linear carbon–mercury–carbon bonds. There are no significant intermolecular close approaches, the structure is, therefore, of molecular type.

ISSN:0008-4042    

DOI:10.1139/v70-070

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

Perfluorocyclohexane (PFCH) and perfluoromethylcyclohexane (PFMCH) have been irradiated in the solid state by γ rays of60Co. The electron spin resonance (e.s.r.) spectrum of PFCH irradiated at 77 °K corresponds mainly towhich is tumbling in the matrix above 160 °K and disappears at the transition point (180 °K). When γ irradiation is carried out at 200 °K, C6F11•is also produced, but reacts with PFCH giving a radicalsupposed to beThe e.s.r. spectrum of PFMCH γ irradiated at 77 °K has not been identified; it might be attributable in part to (•C6F11CF3)−. Above 160–170° K, the e.s.r. spectrum corresponds only toThe equal coupling of the four γ fluorines and also the relative intensity 1:4:1 of the three main groups of lines observed above 210 °K suggest that ring inversion occurs with a high rate.We have also studied the radicalsproduced by γ irradiation in the presence of oxygen. The variation of their spectra with temperature, particularly near the transition points, is very characteristic of the motion involved.

ISSN:0008-4042    

DOI:10.1139/v70-071

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The γ-irradiation of dipotassium difluoromalonate monohydrate led to the formation of two molecular configurations of the ĊF2CO2−radical in addition to the previously identified ĊF(CO2−)2radical. A comparison of the α-fluorine coupling in the two forms of the ĊF2CO2−radical indicates that loss of a carboxylate group nearly coplanar with the C—C—C plane in the undamaged molecule is favor

ISSN:0008-4042    

DOI:10.1139/v70-072

出版商:NRC Research Press    

年代:1970

数据来源: NRC

摘要:

The facile synthesis of 3,6-anhydro-5-deoxy-5-fluoro-1,2-O-isopropylidene-α-L-idofuranose (4) from readily available precursors is described. The1H and19F nuclear magnetic resonance spectra of this derivative have been analyzed. Interestingly, the fluorine substituent exhibits detectable spin coupling with all ring protons except H-2. Both of the anomeric 1,2-di-O-acetyl derivatives of (4) have also been studied.

ISSN:0008-4042    

DOI:10.1139/v70-073

出版商:NRC Research Press    

年代:1970

数据来源: NRC