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研究一些含[Mo_3S_3]折叠簇环的原子簇化合物中[Mo_3S_3]簇环的类芳香性本质,引起了我们对单环芳香烃电子结构特征的兴趣,以便验证所用量子化学理论方法的可靠性。采用Edmistan-Ruedenberg能量定域化方法把CNDO/2计算得到的正则分子轨道(CMO)变换为定域化分子轨道(LMO),从而计算了C_3H_3~+,C_3H_3~-,C_4H_4~(2+),C_4H_4(环丁二烯),C_4H_4~(2-),C_5H_5~+,C_5H_5~-,C_6H_6,C_6H_6~(2-),C_6H_8(己三烯),C_7H_7~+,C_7H_7~-,C_8H_8~(2+),C_8H_8,C_8H_8~(2-),C_8H_8(环辛四烯),C_9H_9~-和C_9H_9~-等18个实际存在或理论上设想的分子(或离子)的LMO.结果表明,在所研究的这些分子中存在着明显地分离出来的σ键和π键两类LMO;所有的σ键都是二中心双电子键:典型的π键有二中心,三中心和四中心等三种双电子键;具有单一的经典价键结构的分子仅含有二中心键;非单一经典价键结构的分子存在着多中心键:具有芳香性的分子(或离子)的π电子体系则是连续而又封闭的.
The aromatic nature of [Mo_3S_3] clusters in some cluster compounds containing [Mo_3S_3] folded cluster rings has led to our interest in the electronic structure of monocyclic aromatic hydrocarbons in order to verify the reliability of the theoretical methods used in quantum chemistry. By using Edmistan-Ruedenberg energy localization method, the regular molecular orbitals (CMO) calculated by CNDO / 2 are transformed into localized molecular orbital (LMO), and then C_3H_3 ~ +, C_3H_3 ~ -, C_4H_4 ~ , C_4H_4 (cyclobutadiene), C_4H_4 ~ (2 -), C_5H_5 ~ +, C_5H_5 ~ -, C_6H_6, C_6H_6 ~ (2 -), C_6H_8 (hexatriene), C_7H_7 ~ +, C_7H_7 ~, C_8H_8 ~ (LMO) of 18 physically or theoretically envisioned molecules such as C 8 H 8, C 8 H 8, C 8 H 8 2-, C 8 H 8 (cyclooctatetraene), C 9 H 9 - and C 9 H 9 - Among these studied molecules, there are two types of LMOs that are obviously separated out from each other: σ bond and π bond; all σ bonds are di-centric double electron bonds: the typical π bond has two centers, three centers and four centers Type double bond; the molecule with a single classical valence bond structure contains only two center bonds; the multi-center bond exists in the molecule with a non-single-valence bond structure: the π electron system with aromatic molecules (or ions) And closed.