A photoelectron spectroscopic investigation of tetra-tert-butyltetrahedrane and of tetra-tert-butylcyclobutadiene
A photoelectron spectroscopic investigation of tetra-tert-butyltetrahedrane and of tetra-tert-butylcyclobutadiene
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四叔丁基四面体和四叔丁基环丁二烯的光电子能谱研究
DOI：
10.1021/ja00522a021
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
A. Schmelzer
中科院分区：
文献类型：
--
作者：
E. Heilbronner;T. B. Jones;A. Krebs;G. Maier;K. Malsch;Juergen Pocklington;A. Schmelzer
标题化合物四正丁基四面体 (3) 和四正/正丁基环丁二烯 (6) 以及三环烃 9（与 6 相关）的 He (Ia) 光电子能谱已使用从头算和半经验模型计算在库普曼斯近似中记录和解释。结果表明，从 e 对称性的最高占据分子轨道中除去一个电子，会产生质心/c» 7.9 eV 的典型双峰带，这表明自由基阳离子 3+ 的预期 Jahn-Teller 畸变。理论与实验之间相当好的一致性为理论计算得出的结论提供了可信度，即在1-3中，邻位局域CC a轨道（即局域于四面体的两个相对边缘）之间的交叉项几乎为零，这与立方体中邻位局域CC轨道之间的大相互作用项相反。将6和9的光电子能谱结果与其他环丁二烯衍生物的光电子能谱结果进行比较表明，轨道序列为(=
The He (Ia) photoelectron spectra of the title compounds tetra-zm-butyltetrahedrane (3) and tetra-/m-butylcyclo-butadiene (6) and of the tricyclic hydrocarbon 9 (related to 6) havebeen recorded and interpreted within Koopmans’ approximation using ab initio and semiempirical model calculations. It is shown that removal of an electron from the highest occupied molecular orbital, of e symmetry, leads to a typical double-humped band with centroid/c» 7.9 eV, which is indicative of the expected Jahn-Teller distortion of the radical cation 3+. The rather good agreement between theory and experiment lends credibility to the conclusion derived from the theoretical calculations that in 1-3 the cross term between vicinal, localized CC a orbitals (ie, localized on two opposed edges of the tetrahedron) is practically zero, in contrast to thelarge interaction term between vicinal, localized CC orbitals incubane. Comparison of our photoelectron spectroscopic results for 6 and 9 with those of other cyclobutadiene derivatives shows that the orbital sequence is(=