Doubly protonated benzene in the gas phase.
Doubly protonated benzene in the gas phase.
复制标题
气相中的双质子化苯。
DOI：
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发表时间：
2006
影响因子：
2.9
通讯作者：
H. Schwarz
中科院分区：
文献类型：
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作者：
J. Roithová;D. Schröder;R. Berger;H. Schwarz
利用串联质谱研究了双质子化苯的结构和单分子裂解。相应的双阳离子分别由1，3-和1，4-环己二烯的电子电离（EI）产生。结果表明，1，3-环己二烯的EI导致双质子化苯的单重态，而1，4-环己二烯的EI产生单重态和三重态的混合物。双质子化的苯的单分子断裂仅通过脱氢进行，导致苯二价离子。质子化苯的质子亲合势（PA）分别为PA（C（6）H（7）（+））（Meta）= 1.9 +/- 0.3 eV（质子化发生在间位）、PA（C（6）H（7）（+））（邻位）= 1.5 +/- 0.2 eV和PA（C（6）H（7）（+））（帕拉）= 0.9 +/- 0.2 eV。各方面的实验进行了比较与密度泛函理论计算和一般良好的协议。
Structural aspects and the unimolecular fragmentations of doubly protonated benzene are studied by means of tandem-mass spectrometry. The corresponding dications are generated by electron ionization (EI) of 1,3- and 1,4-cyclohexadienes, respectively. It is suggested that EI of 1,3-cyclohexadiene leads to the singlet state of doubly protonated benzene, whereas EI of 1,4-cyclohexadiene yields a mixture of singlet and triplet states. Unimolecular fragmentation of doubly protonated benzene exclusively proceeds via dehydrogenation leading to the benzene dication. The proton affinities (PAs) of protonated benzene amount to PA(C(6)H(7)(+))(meta) = 1.9 +/- 0.3 eV for protonation taking place at the meta-position, PA(C(6)H(7)(+))(ortho) = 1.5 +/- 0.2 eV, and PA(C(6)H(7)(+))(para) = 0.9 +/- 0.2 eV, respectively. Various facets of the experiments are compared with density functional theory calculations and generally good agreement is found.