摘要:

The crystal and molecular structure of the molybdenum tetracarbonyl complex of 1,4-diphenyl-2,2′,3,3′,5,5′,6,6′-octamethylcyclo-1,4-diphosph a-2,3,5,6-tetrasilahexane, (PhPSi2Me4)2Mo(CO)4, has been determined by single crystal X-ray diffraction. The crystals are monoclinic, space groupP21/n, witha = 15.983(5),b = 19.316(6),c = 10.580(3) Å, β = 99.99(2)°V = 3217(2) Å3,Z = 4, and ρcalcd = 1.356 g/cm3. The structure was solved by Patterson heavy atom methods and was refined by full-matrix least-squares procedures to a finalR1of 3.3% andR2of 4.3%, for 6342 reflections with intensities greater than 2σ. The coordination of the boat-shaped (PhPSi2Me4)2ligand to molybdenum tetracarbonyl produces a distorted octahedral environment about the metal. The mean Si—Si (2.358(14) Å) and P—Si (2.275(19) Å) distances are not greatly altered from the values found for them in the free ligand. The structural consequences of P → Si π-bonding in the latter are therefore minimal. The relatively long P—Mo (mean length 2.592(13) Å) distances are interpreted as the result of reduced back-bonding from the metal, caused by the presence of the relatively electropositive silyl groups on phosphorus. Consistently, the equatorial Mo—C bonds, which aretransto the diphosphine ligand, are shorter (mean length 1.968(19) Å) than the corresponding bonds to the axial carbonyl groups (mean length 2.021(15) Å).

ISSN:0008-4042    

DOI:10.1139/v79-305

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Excess volume data for binary liquid mixtures of butylamine with aromatic and aliphatic hydrocarbons were measured as a function of composition dilatometrically at 303.15 and 313.15 K. The hydrocarbons include: benzene, toluene, three isomeric xylenes, hexane, heptane, and octane. The values ofVEwere found to be positive over the entire range of composition in all the eight systems at both the temperatures. The positive values were ascribed to the break-up of hydrogen bonds in the aggregates of amine by the hydrocarbons.

ISSN:0008-4042    

DOI:10.1139/v79-306

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Solubility equilibria of hydroxylapatite, chlorapatite, and a series of their solid solutions were investigated at 37 °C in the pH range 4.25 to 7.40 and their solubility products evaluated. Proof could be obtained for their stoichiometric dissolution.

ISSN:0008-4042    

DOI:10.1139/v79-307

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Photochemical decomposition of selected diarylcadmium compounds in dilute benzene solutions was investigated. This reaction was found to involve initial cleavage of the aryl–cadmium bonds followed by coupling of the aryl radicals to give symmetrical biaryls in good yields. Arylation products were obtained in only 5–25% yields, in contrast with the photolysis of iodoaromatic compounds in benzene which gives arylation products in high yields. Diarylcadmium compounds derived from polynuclear aromatic compounds, e.g. di(p-biphenyl)cadmium and di(α-naphthyl)cadmium gave, under the same conditions, predominantly hydrogen transfer products. In carbon tetrachloride, photolysis of diarylcadmium compounds gave chloroarenes in high yields.

ISSN:0008-4042    

DOI:10.1139/v79-308

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The vacuum dehydration of copper(II) sulphate pentahydrate has been shown to pass through the transitory trihydrate state before proceeding to the monohydrate composition. Based on this, the heat of solution data for the high-energy modification hydrates have been reinterpreted and the low-energy crystalline hydrates of various compositions have been prepared and their heats of solution measured. From the heat of solution data the maximum energy difference expressed in kcal/mol heptahydrate appears to be of the right order of magnitude to be regarded as the ligand field splitting energy for the hexaaquocopper(II) ion. Similar measurement for the ammine complexes of copper(II) sulphate has also been done and the maximum energy difference was found to agree well with the value of LFSE obtained by spectroscopic method.

ISSN:0008-4042    

DOI:10.1139/v79-309

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The synthesis of title compounds and some aromatic ring substituted analogues is described.

ISSN:0008-4042    

DOI:10.1139/v79-310

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The synthesis of the title compounds is reported. It is shown that, in contrast to benzylic ketones, benzylic oximes are stable to hydrogenolysis conditions necessary for the removal of benzyl protecting groups of carboxylic acids and phenols.

ISSN:0008-4042    

DOI:10.1139/v79-311

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The reaction of crotonyl and dimethylacryloyl chloride with various Schiff bases is described. The resulting β-lactams derived from aliphatic amines all have acisstereochemistry.

ISSN:0008-4042    

DOI:10.1139/v79-312

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

The13C nmr spectra of several isomeric monosubstituted derivatives of 2-methoxytropone together with some dibromo derivatives have been obtained and analysed. Substituent parameters were defined and shown to exhibit additivity. Differences with corresponding parameters for monosubstituted benzene analogs suggest proximity interactions between the 3-substituents and the 2-OCH3group as well as between 7-substituents and the adjacent carbonyl group. The data indicates that the OCH3group is a convenient probe to investigate the orientation of mesomeric electronic charge transfer to the various carbons of the tropone seven-membered ring. Finally, it is demonstrated that13C nmr is quite useful to distinguish between the various substituted 2-methoxytropones.

ISSN:0008-4042    

DOI:10.1139/v79-313

出版商:NRC Research Press    

年代:1979

数据来源: NRC

摘要:

Carbon tetrahalide reacts rapidly with 2-phenylsulfonyl aziridines in the presence of KOH, leading to 2-phenylsulfonyl 2-haloaziridines.Starting with 2-isopropylsulfonyl aziridines, a monochloro and a dichloroaziridine are produced; the Ramberg–Bäcklund reaction is not observed.These halo compounds decompose either thermally or in acidic medium leading toN-substituted α-haloacetamides and α-phenylsulfonylacetamides. 2-Phenylsulfonyl 2-haloaziridines are unreactive toward potassium cyanide or sodium thiophenoxide. Sodium methoxide, sodium ethoxide, or sodium thioethoxide reduce them to 2-phenylsulfonyl aziridines; the reaction depends upon the solvent.

ISSN:0008-4042    

DOI:10.1139/v79-314

出版商:NRC Research Press    

年代:1979

数据来源: NRC