张键, 曹玲华, 刘育亭. 二亚甲基五员杂环的HMO研究[J]. Journal of Xinjiang University (Natural Science Edition in Chinese and English), 1990, (2).DOI:
二亚甲基五员杂环的HMO研究
摘要
利用 HMO 法计算3
4-二亚甲基呋喃(1)和3
4-二亚甲基噻吩(Ⅱ)的分子轨道能级
无论氧和硫采用怎样的杂原子参数值
在它们的8个分子轨道中
ε4和δ5都不可能成为简并轨道
因此它们决不会是双自由基
这从理论上证明了Berson 所说的它们基态都是单线态的结论。根据计算可以预言:只有3
4-二亚甲基富烯(X)在基态时可能是一个三线态分子.
Abstract
3
4-Dimethylenefuran (Ⅰ) and 3
4-dimethylenethiophene (Ⅱ) are notdiradicals.The result of calculation of their HMO energy levels by introducingany parameter values of heteroatom show that ε4 and ε5 are not degenerated intheir eight MOs.The experimental conclusion of Berson that the ground state ofthese molecules are singlet can be proved theoretically.But it can be expect thatthe 3
4-(?)imethylenefulvene (X)may be a triplet molecule in the ground state.