摘要:

Crystals of [Me3Ga2(N2C4H5)3CuO]2are monoclinic,a = 10.766(1),b = 14.419(2),c = 15.174(1) Å, β = 115.923(6)°,Z = 2, space groupP21/c. The structure was solved by Patterson and Fourier syntheses and was refined by full-matrix least-squares procedures to a finalRof 0.047 andRwof 0.060 for 3042 reflections withI ≥ 3σ(I). Details of the preparation and physical properties of the compound are given. The centrosymmetric binuclear complex features copper atoms having distorted square-pyramidal geometry, bonded to four nitrogen atoms and one oxygen atom. Bond distances in the molecule are: Cu—O, 1.923(3), Cu—N, 1.964(4)–2.874(4), Ga—O, 1.825(4) and 1.881(3), Ga—N, 1.952(4)–1.978(5), Ga—C, 1.950(7)–1.979(8), N—N, 1.358(6)–1.385(6), N—C, 1.326(7)–1.352(6), C—C(pyrazolyl), 1.342(9)–1.386(8), C—CH3, 1.487(9)–1.500(10), and C—H, 0.81(10)–1.06(12) Å.

ISSN:0008-4042    

DOI:10.1139/v76-049

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Measurements of the ultrasonic absorption and velocity, and viscosity have been carried out in the system methanol–water at 0, 15, and 25 °C at frequencies from 10 to 50 MHz. The data show the existence of two maxima in the excess absorption as a function of composition. The existence of the two maxima are predicted by the Romanov–Solovyev theory relating the absorption to concentration fluctuations. The magnitude of the excess absorption is calculated at 25 and 0 °C from density, vapour pressure, and diffusion data. New experimental data on density and vapour pressure are presented for this system at 0 °C. The calculated excess absorption is in reasonable agreement with the measured. This indicates that any specific localized intermolecular interactions present in this system could be responsible for at best a smaller portion of the excess ultrasonic absorption, as longer range concentration fluctuations account for essentially all of the excess. Ultrasonic data on the systems methanol–octanol andn-propanol–water are also presented in the course of examining the generality of these phenomena.

ISSN:0008-4042    

DOI:10.1139/v76-050

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Several deuterated aqueous glasses have been pulse-irradiated at 76 K. In addition to the well known visible absorption band of et−, a second intense infrared absorption band, with λmax > 3200 nm, has been found in (a) 50% by volume ethylene glycol, (b) 9.5 MLiCl, and (c) 2.5 and 4 MMgCl2glasses. Electron scavengers decrease the intensities of both bands, but to different extents. An increase in temperature decreases the intensity of the infrared band, but not that of the visible band. These and other features lead us to conclude that the infrared band is due to shallowly trapped electrons which are distinctly different from trapped electrons which absorb in the visible region.The decay of the infrared band extends over several orders of magnitude in time and, unlike that of the visible band, is independent of wavelength. In the two chloride glasses the decay of the infrared band is accompanied by emission (λmax ≈ 410 nm) and is probably due to a spur reaction between an electron and hydroxyl radical to form excited hydroxide ion. No emission is found in the ethylene glycol glass, but growth of the visible band matches the decay of the infrared band in this case.By comparing the amount of Ag0produced in an ethylene glycol glass containing Ag+with the decrease in intensity of the infrared and visible bands, we obtain ϵ1400 = (5.7 ± 0.8) × 103 M−1cm−1. From the shape of the infrared band, which is Lorentzian on the high energy side, we estimate λmax ≈ 3600 nm and ϵmax ≈ 4.9 × 104 M−1cm&mi

ISSN:0008-4042    

DOI:10.1139/v76-051

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Nickel di-n-butyldithiocarbamate and nickel diisopropyldithiophosphate inhibit the α,α′-azo-bis-isobutyronitrile initiated autoxidation of tetralin, styrene, and cyclohexa-1,4-diene by scavenging chain propagating alkylperoxy radicals. The rapid reaction of these complexes with alkylperoxy radicals has been confirmed by low temperature electron spin resonance studies. Kinetic data obtained by these two techniques are reported. Product studies suggest that alkylperoxy radicals (ROO•) are reduced by reaction with the nickel complex to the alcohol (ROH) while the nickel complex is oxidized to a Lewis acid.

ISSN:0008-4042    

DOI:10.1139/v76-052

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Alkyl hydroperoxides are shown to react with nickel dialkyldithiocarbamates and nickel dialkyldithiophosphates in the liquid-phase at 30 °C to generate free radicals. These radicals are capable of inducing the decomposition of the hydroperoxide and destroying the nickel complex. Rates of radical generation, as determined from hydrocarbon autoxidation, are similar to rates of complex disappearance and areca. 1/5th rates of hydroperoxide disappearance. Rates of disappearance of both reactants are retarded by the addition of hydrogen atom donating antioxidants, the rate of hydroperoxide disappearance is reduced to the rate of radical generation and the rate of complex disappearance is significantly less than the rate of radical generation. These results are consistent with a mechanism for decomposition which involves cycling of the nickel complex. Decomposition of cumene hydroperoxide to α-cumyl alcohol, α-methylstyrene and acetophenone suggests the intermediacy of cumyloxy radicals in this system while the electron spin resonance spectroscopic method indicates that alkylperoxy radicals are also transient intermediates.

ISSN:0008-4042    

DOI:10.1139/v76-053

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The mechanism of polarographic maxima of the first kind, positive and negative, was investigated. Tracks of suspended particles photographed at 16 fps were analysed and found to obey a power law consistent with increasing speeds towards the mercury drop surface pointing to even more rapid movement of the mercury surface. The motions of large particles trapped in specific parts of the flow patterns were photographed and their velocities analysed. Particle motion in the mainly stagnant layer below the drop outlined by interferometry was contrasted with the motion of particles in the streaming region. Finally particles deposited on the drop were used to show the motion of the surface of the bottom hemisphere of the drop. High speed motion picture photography was used to record the change of shape of the drop on sudden polarization and to find the resonant frequency of the drop.

ISSN:0008-4042    

DOI:10.1139/v76-054

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Ceric ammonium nitrate, in aqueous acetic acid buffered with sodium acetate, rapidly oxidizes 2,2′-dipyrromethanes to the corresponding 2,2′-dipyrroketones.

ISSN:0008-4042    

DOI:10.1139/v76-055

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Two related butenolides, one having fungitoxic properties, were obtained from the reaction of acetophenone with citraconic anhydride in the presence ofn-butyllithium. The butenolides rearranged to a 3(2H)-furanone related to bullatenone on acid treatment.

ISSN:0008-4042    

DOI:10.1139/v76-056

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

The γ-lactone obtained from acid treatment of dihydroisopimaric acid was found to have acis-A/B ring fusion. This structure revision was based on13C nmr chemical shift data and spin–lattice relaxation time (T1) measurements. Using the same methods, the δ-lactone derived from the same acid was shown to have the previously proposed structure.

ISSN:0008-4042    

DOI:10.1139/v76-057

出版商:NRC Research Press    

年代:1976

数据来源: NRC

摘要:

Nitration ofp-cymene in acetic anhydride gives a mixture ofcis- andtrans-1-isopropyl-4-methyl-4-nitro-1,4-dihydrophenyl acetate as the main product as well as 2- and 3-nitro-p-cymene andp-nitrotoluene. Acid-catalysed methanolysis of the acetoxynitro adduct gives a mixture of thecis- andtrans-methoxynitro adducts. Under basic conditions the acetate adduct is converted into the corresponding alcohol which is in turn rearomatized to 2-isopropyl-4-methylphenol. The adducts rearomatize to 2-nitro-p-cymene in strong acid.

ISSN:0008-4042    

DOI:10.1139/v76-058

出版商:NRC Research Press    

年代:1976

数据来源: NRC