A further study of HCO+ dissociative recombination
摘要:
The rate coefficient for the dissociative recombination of HCO+ has been measured using a new flowing afterglow technique which employs a movable Langmuir probe to measure electron density and a movable mass spectrometer to measure ion density, both as a function of distance along the flow. A value of 2.2×10−7 cm3 s−1 has been found at 300 K. An analysis of the excitation state of the ions indicates that more than 93% are in the v=0 state while the rest have ∼0.1 eV of internal energy. A discussion of recent theoretical controversy concerning this ion is given.
Use of the vinyl group as an efficient protecting group for azole N- atoms: Synthesis of polyfunctionalized imidazoles and thieno[2,3-d] ⇌ [3,2-d]imidazole
作者:David J. Hartley、Brian Iddon
DOI:10.1016/s0040-4039(97)00957-x
日期:1997.6
2 → 5 → 4 via Br → MgBr and other exchange reactions. Efficient removal of the vinyl groups from the resulting polyfunctionalized imidazoles was achieved with ozone or potassium permanganate. An extension of this methodology has allowed the first synthesis of thieno[2,3-d] ⇌ [3,2-d]-imidazole.
由2,4,5-三溴咪唑和1,2-二溴乙烷制得2,4,5-三溴-1-乙烯基咪唑,并通过Br→MgBr等交换反应以2→5→4的顺序选择性取代其Br原子反应。用臭氧或高锰酸钾可有效地从所得的多官能化咪唑中除去乙烯基。此方法的扩展允许首次合成噻吩并[2,3- d ]⇌[3,2- d ]-咪唑。
Deuterated methyl cation reactions with atomic oxygen
The rate constants for the reactions between CDitnH-itn+ and O have been measured and found to be fast, independent of isotope.The branching ratio for these reactions has been found to be statistical. Since decay of metastable triplet CD2HO+ shows a large isotope effect, it was thought that the present reactions might also do so. The fact that the present experiments do not show this large isotope
测量了CD itn H - itn +和O之间反应的速率常数,发现该速度常数快,与同位素无关,已发现这些反应的支化比是统计的。由于亚稳态三重态CD 2 HO +的衰变显示出较大的同位素效应,因此认为目前的反应也可以这样做。本实验未显示出如此大的同位素效应这一事实归因于反应CH 3 + + O←HCO + + H 2的放热性大,这打开了一些不涉及亚稳态三重态CD 2 HO +的替代途径。 作为中间体。
The proton affinities of CO and CO2 and the first hydration energy of gaseous H3O+ from mass spectrometric investigations of ions in rich flames of C2H2
作者:Allan N. Hayhurst、Stephen G. Taylor
DOI:10.1039/b102973h
日期:——
temperatures when a sample is expanded supersonically into a vacuum chamber. However, a sample from a flame is perturbed by being cooled somewhat by the cooler metal around the inlet orifice, through which the flame gas enters the mass spectrometer. After allowing for the effects of such cooling, the enthalpy change of reaction (8) was determined from measurements of [CHO+]/[H3O+] to be − 120 ± 18 kJ mol−1
富含燃料的氧乙炔火焰(无烟灰且压力为 1 bar)已被采样到质谱仪中。火焰使用二氧化碳作为稀释剂。发现这些火焰中的主要正离子是CHO+、CHO2+、C3H3+、H3O+和H3O+·H2O。离子 CHO+ 和 CHO2+ 参与平衡:涉及 H2O、CO 和 CO2 之间的质子转移。使用 CO2 作为稀释剂可以在燃烧气体的下游很远的地方检测到 CHO+ 和 CHO2+。使用具有相对较低的主要比热比的三原子 CO2 有趣地减少了气体样品在超音速膨胀进入质谱仪期间所经历的冷却;同样,来自以 CO2 作为稀释剂的火焰的样品在超音速膨胀中花费的时间比来自以 Ar 作为稀释剂的火焰的样品要少。实际上,发现以 CO2 作为稀释剂的火焰不受这种常见的采样扰动的影响,当样品超音速膨胀到真空室中时,快速平衡会适应快速下降的温度。然而,来自火焰的样品被入口孔周围的较冷金属稍微冷却而受到干扰,火焰气体通过入口孔进入质谱仪。在考虑到这种冷却的影响后,反应
Oxidation of Alkyl Ions, C<i><sub>n</sub></i>H<sub>2</sub><i><sub>n</sub></i><sub>+1</sub><sup>+</sup> (<i>n</i> = 1−5), in Reactions with O<sub>2</sub> and O<sub>3</sub> in the Gas Phase
作者:Skip Williams、W. B. Knighton、Anthony J. Midey、A. A. Viggiano、Stephan Irle、Qingfang Wang、Keiji Morokuma
DOI:10.1021/jp031099+
日期:2004.3.1
product ion branching fractions are reported for the reactions of CH3+, C2H5+, s-C3H7+, s-C4H9+, t-C4H9+, and t-C5H11+ with O2 and O3 at 300 K in a variable-temperature selected-ion flow tube (VT-SIFT). The reaction rate constant for CH3+ with O3 is large and approximately equal to the thermal energy capture rate constant given by the Su−Chesnavich equation. The C2H5+, s-C3H7+, and s-C4H9+ ions are somewhat
Temperature dependence of rate coefficients for reactions of ions with dipolar molecules
作者:D.C. Clary、D. Smith、N.G. Adams
DOI:10.1016/0009-2614(85)80425-5
日期:1985.9
We present a comparison of theoretical and experimental rate coefficients for the reactions of H3+, HCO+, H−, C+ and O+ with HCN, and H3+ with HCl, over the temperature range 205–540 K. The theoretical results are obtained using an adiabatic capture theory which is selective in the initial rotational states of the reacting dipolar molecules. The experiments were performed using a variable-temperature