Reactions of Carbocations with Unsaturated Hydrocarbons: Electrophilic Alkylation or Hydride Abstraction?
作者:Herbert Mayr、Gabriele Lang、Armin R. Ofial
DOI:10.1021/ja0121538
日期:2002.4.1
published empirical electrophilicity parameters E of the benzhydrylium ions. Therefore, the linearfreeenergyrelationship log k(20 degrees C) = s(E + N) could be employed to characterize the hydride reactivities of the hydrocarbons by the nucleophilicity parameters N and s. The similarity of the slopes s for hydride donors and pi-nucleophiles allows a direct comparison of the reactivities of these different
二苯甲基阳离子用作参考亲电试剂,以确定不饱和烃的氢化物供体反应性。通过紫外-可见光谱和电导率测量跟踪反应动力学,发现氢化物转移过程的二级速率常数几乎与所用的溶剂或反离子无关。速率常数与先前公布的二苯甲基离子的经验亲电性参数 E 线性相关。因此,线性自由能关系 log k(20 摄氏度) = s(E + N) 可用于通过亲核性参数 N 和 s 来表征烃的氢化物反应性。
ESR investigation of radical cations formed from aromatics and heteroaromatics adsorbed on molybdenum-aluminum oxide surfaces
作者:L. Petrakis、P. L. Meyer、Gerald L. Jones
DOI:10.1021/j100446a019
日期:1980.5
C-H Bond Strength of Naphthalene Ion. A Reevaluation Using New Time-Resolved Photodissociation Results
作者:Yen-Peng Ho、Robert C. Dunbar、Chava Lifshitz
DOI:10.1021/ja00129a013
日期:1995.6
The dissociation rates and branching ratios for naphthalene ion (naphthalene-d(8) ion) have been measured by time-resolved photodissociation at an internal energy of 7.10 (7.13) eV. Dissociation rate constants of 6450 (2360) s(-1) were observed, with acetylene loss being somewhat favored over hydrogen atom and hydrogen molecule losses. Using simple RRKM theory, these results were modeled along with prior information from time-resolved dissociative photoionization and from photoelectron photoion coincidence to give rate-energy curves. Extrapolated to threshold, bond energies of 4.48 eV for H atom loss and 4.41 eV for acetylene loss were derived, in agreement with predictions from independent thermochemical data. The C-H bond energy (4.48 eV) is discussed relative to those for neutral aromatic hydrocarbons (4.8 eV) and benzene ion (3.7 eV).