Department of Physics, Atmospheric Sciences and Geoscience, Jackson State University, 1400 J. R. Lynch Street, P.O. Box 17660, Jackson, Mississippi 39217, USA.
J Phys Chem A. 2011 Aug 11;115(31):8682-90. doi: 10.1021/jp1122773. Epub 2011 Jul 19.
For the first time, a theoretical study has been performed on the prototypical decathio[10]circulene (C(20)S(10)) species, which is an analogue of the novel octathio[8]circulene "Sulflower" molecule (C(16)S(8)). Examinations of the singlet and triplet states of C(20)S(10) were made at the B3LYP/6-311G(d) level. Local minima of C(2) and C(s) symmetry were found for the lowest singlet and triplet states, respectively. The stability of C(20)S(10) was assessed by calculating the ΔH°(f) of C(16)S(8) and C(20)S(10) and the ΔH(o) for their decomposition into C(2)S units. Frontier molecular orbital plots show that structural adjacent steric factors along with the twist and strain orientations of C(20)S(10) do not disturb the aromatic π-delocalizing effects. In fact, C(20)S(10) maintains the same p(z) HOMO character as C(16)S(8). These similarities are further verified by density-of-states characterization. Calculated infrared spectra of C(16)S(8) and C(20)S(10) show broad similarities. Molecular electrostatic potential results reveal that eight of the peripheral sulfur atoms are the most electronegative atoms in the molecule, while the interior ten-membered ring exhibits virtually no electronegativity.
首次对典型的十并苯[10]环癸烯（C(20)S(10)）物种进行了理论研究，它是新型八并苯[8]环癸烯“Sulflower”分子（C(16)S(8)）的类似物。在 B3LYP/6-311G(d)水平上对 C(20)S(10)的单重态和三重态进行了检查。分别为最低单重态和三重态找到了 C(2)和 C(s)对称的局部最小值。通过计算 C(16)S(8)和 C(20)S(10)的 ΔH°(f)以及它们分解为 C(2)S 单元的 ΔH(o)来评估 C(20)S(10)的稳定性。前沿分子轨道图表明，结构相邻的空间位阻因素以及 C(20)S(10)的扭曲和应变方向不会干扰芳香π离域效应。事实上，C(20)S(10)保持与 C(16)S(8)相同的 p(z)HOMO 特征。这些相似性通过态密度特征进一步得到验证。计算的 C(16)S(8)和 C(20)S(10)的红外光谱显示出广泛的相似性。分子静电势结果表明，分子中最具电负性的原子是八个外围硫原子，而内部的十个成员环几乎没有电负性。
