单卤卡宾自由基阴离子(CHX的反应性- ˙; X = F,Cl和Br)和相应的负碳离子(CH 2 X - ; X = Cl和Br)在气相中
摘要:
单卤素取代的卡宾自由基阴离子,CHX的气相反应- ˙(X = F,Cl和Br)和相应的负碳离子,CH 2 X -(X = Cl和Br)与卤代甲烷和有机酯已经检查使用傅里叶变换离子回旋共振(FT-ICR)质谱。含氯和溴的(自由基)阴离子通过S N 2取代与母体的氯代氨基甲酸酯和溴代氨基甲酸酯反应,而S N 2和/或B AC 2反应则与三氟乙酸的甲酯和碳酸二甲酯发生反应。结果的主要特征是:(i)给定的卡宾自由基阴离子被CH 2取代的S N 23 Cl或CH 3 Br的反应效率不及相应的碳负离子的反应,( ii)自由基阴离子与碳酸二甲酯的反应效率不及碳负离子。( iii)S N 2取代对自由基负离子的重要性不如对碳负离子的重要性。对于两种类型的离子,在与两种羰基化合物( iv)的反应中,碳负离子中,随着卤素原子从氯变成溴,B AC 2途径变得相对更重要。根据整个过程的热力学,结合对可描述这些气相
A tandem mass spectrometer has been used to measure cross sections and product distributions for reactions of the selectively solvated anions OH-(H2O)(n) with the neutral molecules CH3Cl (n = 0, 1, or 2) and CH3Br (n = 0 or 1) over the relative energy range 0.1-5 eV. The reactions observed include nucleophilic displacement, proton transfer, and collision-induced dissociation. With the unhydrated reactant ion OH-, the exoergic nucleophilic displacement channel dominates at low energy, and the endoergic proton transfer channel competes effectively at energies above threshold. Increasing hydration of the reactant ion decreases both nucleophilic displacement and proton transfer, the latter drastically, leaving collision-induced dissociation as the major process above 1 eV.
Dynamics of the Gas-Phase Reactions of Chloride Ion with Fluoromethane: High Excess Translational Activation Energy for an Endothermic S<sub>N</sub>2 Reaction
作者:Laurence A. Angel、Sandra P. Garcia、Kent M. Ervin
DOI:10.1021/ja012031f
日期:2002.1.1
Guided ion beam tandem mass spectrometry techniques are used to examine the competing product channels in the reaction of Cl(-) with CH(3)F in the center-of-mass collisionenergyrange 0.05-27 eV. Four anionic reaction products are detected: F(-), CH(2)Cl(-), FCl(-), and CHCl(-). The endothermic S(N)2 reaction Cl(-) + CH(3)F --> CH(3)Cl + F(-) has an energy threshold of E(0) = 181 +/- 14 kJ/mol, exhibiting
Ingemann, Steen; Nibbering, Nico M.M., Journal of the Chemical Society. Perkin transactions II, 1985, p. 837 - 840
作者:Ingemann, Steen、Nibbering, Nico M.M.
DOI:——
日期:——
Reactivity of mono-halogen carbene radical anions (CHX<sup>–</sup>˙; X = F, Cl and Br) and the corresponding carbanions (CH<sub>2</sub>X<sup>–</sup>; X = Cl and Br) in the gas phase
作者:Monique Born、Steen Ingemann、Nico M. M. Nibbering
DOI:10.1039/p29960002537
日期:——
an SN2 and/or a BAC2 reaction occurs with the methyl ester of trifluoroacetic acid and dimethyl carbonate. The main features of the results are: (i) the SN2 substitution of a given carbene radical anion with CH3Cl or CH3Br is less efficient than this reaction of the corresponding carbanion, (ii) the radical anions react less efficiently with dimethyl carbonate than the carbanions, (iii) the SN2 substitution
单卤素取代的卡宾自由基阴离子,CHX的气相反应- ˙(X = F,Cl和Br)和相应的负碳离子,CH 2 X -(X = Cl和Br)与卤代甲烷和有机酯已经检查使用傅里叶变换离子回旋共振(FT-ICR)质谱。含氯和溴的(自由基)阴离子通过S N 2取代与母体的氯代氨基甲酸酯和溴代氨基甲酸酯反应,而S N 2和/或B AC 2反应则与三氟乙酸的甲酯和碳酸二甲酯发生反应。结果的主要特征是:(i)给定的卡宾自由基阴离子被CH 2取代的S N 23 Cl或CH 3 Br的反应效率不及相应的碳负离子的反应,( ii)自由基阴离子与碳酸二甲酯的反应效率不及碳负离子。( iii)S N 2取代对自由基负离子的重要性不如对碳负离子的重要性。对于两种类型的离子,在与两种羰基化合物( iv)的反应中,碳负离子中,随着卤素原子从氯变成溴,B AC 2途径变得相对更重要。根据整个过程的热力学,结合对可描述这些气相
Translational Energy Dependence of Cross Sections for Reactions of OH-(H2O)n with CH3Cl and CH3Br
作者:Peter M. Hierl、John F. Paulson、Michael J. Henchman
DOI:10.1021/j100042a047
日期:1995.10
A tandem mass spectrometer has been used to measure cross sections and product distributions for reactions of the selectively solvated anions OH-(H2O)(n) with the neutral molecules CH3Cl (n = 0, 1, or 2) and CH3Br (n = 0 or 1) over the relative energy range 0.1-5 eV. The reactions observed include nucleophilic displacement, proton transfer, and collision-induced dissociation. With the unhydrated reactant ion OH-, the exoergic nucleophilic displacement channel dominates at low energy, and the endoergic proton transfer channel competes effectively at energies above threshold. Increasing hydration of the reactant ion decreases both nucleophilic displacement and proton transfer, the latter drastically, leaving collision-induced dissociation as the major process above 1 eV.