摘要:

Reaction of mercuric iodide withN,N,N′,N′-tetraethylthiuramdisulfide (TETD),gave bis(iodo-N,N-diethyldithiocarbamatomercury(II)) and diiodo-N,N,N′,N′-tetraethylthiuramdisulfidemercury(II). The crystal of the former was mono-clinic witha = 7.645(3),b = 7.787(4),c = 18.005(7) Å and β = 102.08(4)°. The space group wasP21/c, with two dimeric molecules per unit cell. Diffractometer measured intensities of 1727 observed reflections were used to determine the structure; the finalRfactor being 0.059. The mercuric ion was three-coordinated with two Hg—S distances of 2.422(4) and 2.644(4) Å and one Hg—I distance of 2.641(1) Å. The dimer had a centre of symmetry and formed an eight-membered ring.

ISSN:0008-4042    

DOI:10.1139/v77-011

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The synthesis, physical properties, and electron spin resonance of frozen solutions of CoTAAB(NO3)2(TAAB = tetrabenzo[b,f,j,n] [1,5,9,13]tetraazacyclohexadecine) are reported. The spin Hamiltonian parameters were elucidated by simulation of spectra assuming axial g and59Co hyperfine tensors and including nuclear quadrupole and Zeeman contributions. Electron spin resonance spectra in solvents such as methanol, acetone, and dimethylformamide are typical for a low spin complex (S = 1/2) and are nearly identical withand. In pyridine and quinoline a complex with a molar ratio solvent/ligand of 1:1 is formed with the solvent which givesandmuch closer to. In strong Lewis bases, such as piperidine, a 2:1 complex is formed and no esr signal is found. Evidence is presented to show that these 2:1 complexes with strong Lewis bases are S = 1/2 complexes with a low lying S = 3/2 state that is partially populated at room temperatures. This behaviour is accounted for in terms of a theory derived for a2A1ground state with a low lying quartet state which could become the ground state in strong basic solvents.

ISSN:0008-4042    

DOI:10.1139/v77-012

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Excess volume data for mixtures of 1-propanol, 1-butanol, 1-pentanol, and 1-hexanol with methylethylketone were determined at 303.15 and 313.15 K. These volumes are negative with 1-propanol and increasingly positive with the higher homologs, suggesting that the structure-making effect of the ketone outweighs the structure-breaking effect in the first mixture of the series while the structure-breaking effect dominates in the other three mixtures. Further, the temperature coefficient ofVEwas found to be positive in all four mixtures.

ISSN:0008-4042    

DOI:10.1139/v77-013

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

D nmr lineshape information was obtained from the echo response following a pair of phase shifted pulses using a method first proposed by Clark. In this manner the D quadrupole coupling constant and asymmetry parameter for D2O inp-dioxane•17D2O were found to be 217 kHz and 0.10 at 63 K. The D nmr lineshape for ethylene oxide-d4•7H2O shows that at 17 K the guest molecules are held rigidly in their cages. At higher temperatures the doublet lineshape collapses to a broad structureless line characteristic of molecules for which the reorientational modes vary from cage to cage.

ISSN:0008-4042    

DOI:10.1139/v77-014

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Reaction of β-ketoglutaric acid with benzil in ethanolicKOHfurnished the 1:1 adduct7. Hydrolysis and partial decarboxylation gave the monoacid8, the structure of which was erroneously reported to be5in the earlier literature.

ISSN:0008-4042    

DOI:10.1139/v77-015

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The concentrations have been measured of carbenium ions formed when diphenylethylene and diphenylpropene react with boron trifluoride and water in methylene chloride solution. With both these olefins it appeared necessary that two boron trifluoride molecules should be present for every water molecule to form the carbenium ion. Also the ionic species formed showed a very high degree of ionic dissociation. Diphenylethylene rapidly formed the cyclized dimer, and as a side reaction formed some triphenylmethylcarbenium ions. The diphenylpropene gave a diphenylcarbenium ion that appeared stable, but the accompanying anion was thought to be unstable and rearranged to a more stable form which disrupted the dependences on the concentrations of original reactants.

ISSN:0008-4042    

DOI:10.1139/v77-016

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Mössbauer spectra of57Fe probe atoms in the spinel Co2.94Fe0.06S4indicate the existence of a magnetic transition atTtr ≈ 95 K in the parent phase Co3S4. The spectrum observed belowTtrconsists of a six-line magnetic spectrum and a two-line quadrupole spectrum. AboveTtrthe six-line spectrum collapses to a single line superposed on the two-line quadrupole spectrum. Consideration of the Mossbauer parameters and of the area ratio of the component spectra suggests that the atomic occupancy of the spinel lattice is [Co0.968Fe0.032][Co0.986Fe0.014]2S4, the Fe atoms having preference for the tetrahedrally coordinated cation site

ISSN:0008-4042    

DOI:10.1139/v77-017

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

The accelerating effect of added dimethyl sulfoxide on the rate of hydroxide-catalyzed ionization of chloroform in water has been examined in terms of the solvation of reactants and transition state. Enthalpies of solution of chloroform in water, DMSO, and mixtures of the two have been measured. From these, together with enthalpies of activation for the detritiation of chloroform, and enthalpies of transfer of hydroxide ion from water to aqueous DMSO mixtures, transition state enthalpies of transfer have been calculated. The reaction is accelerated by small concentrations of DMSO because of increased transition state solvation, but by large DMSO concentrations due to reduced solvation of hydroxide ion. Transition state solvation is unlike that of the reactants, but resembles that expected for CCl3−ion.

ISSN:0008-4042    

DOI:10.1139/v77-018

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Rates of oxidation of aqueouso-, andp-hydroxyacetophenone with alkaline hydrogen peroxide to yield catechol and hydroquinone, respectively, have been followed spectrophotometri-cally. Both ketones showed smooth pseudo first-order behaviour, theorthoisomer yielding rate constants in the range 2.6 to 6.6 × 10−2 min−1at 0 °C, and theparaisomer of 0.73 to 7.10 × 10−2 min−1at 35 °C for the concentrations of hydrogen peroxide and base used. The order in hydrogen peroxide was, unexpectedly, found to be 1.4. A simple test established that this fractional order was probably not the result of hydrogen peroxide involvement in simultaneous first- and second-order processes of differing rates. Other plausible pathways to explain this are proposed.

ISSN:0008-4042    

DOI:10.1139/v77-019

出版商:NRC Research Press    

年代:1977

数据来源: NRC

摘要:

Reaction of [n-Bu4N]2[Re4(CO)16] with AgBF4in acetonitrile affords the compound [(CH3CN)3Re(CO)3][BF4]. The latter crystallizes in monoclinic space groupP21/cwith unit cell dimensionsa = 11.021(5) Å,b = 11.136(5) Å,c = 12.980(6) Å, β = 96.906(25)°, and four molecules per unit cell. Data were collected by counter methods and the structure was refined using least-squares procedures to giveR = 0.041. The rhenium cation is approximately octahedrally coordinated by six facially arranged ligands. The mean rhenium–nitrogen distance is 2.13 Å, and the mean rhenium–nitrogen–carbon angle in the coordinated acetonitrile is 174.7°.

ISSN:0008-4042    

DOI:10.1139/v77-020

出版商:NRC Research Press    

年代:1977

数据来源: NRC