Gao Ying, Xu Hong-Liang, Zhong Rong-Lin, Sun Shi-Ling, Su Zhong-Min
Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, 130024, Jilin, People's Republic of China.
J Mol Model. 2014 Apr;20(4):2201. doi: 10.1007/s00894-014-2201-0. Epub 2014 Mar 26.
Due to the unusual properties of the Möbius cyclacenes (MC) such as π electrons, MC has drawn the extensive attention of scientists. In the present work, six [n]MC (n = 13-18, n is the number of benzenoid rings) were systematically investigated to explore the size-dependent effects on structures, electro-optical properties, and frontier molecule orbits (FMO). According to the dihedral angles (C-C-C-C), the un-twisted area and twisted area are defined, respectively. The twisted area mainly distributes on seven or eight benzenoid rings for [n]MC (n = 13-18). Further, the polarizability (α₀) and first hyperpolarizability (β₀) of [n]MC (n = 13-18) were calculated with three density functional methods (BHandHLYP, Cam-B3LYP, and M06-2X). Results show that the α₀ values increase linearly with increasing the number (n) of benzenoid rings. Significantly, the β₀ values are increased to zigzag with increasing the number (n) of benzenoid rings. Interestingly, when n is even (14, 16, and 18), the electron transfer is from the twisted area to the un-twisted area, but the electron transfer is from the un-twisted area to the twisted area when n is odd (13, 15, and 17).
由于莫比乌斯并苯（MC）具有诸如π电子等不寻常的性质，它已引起了科学家们的广泛关注。在本工作中，系统地研究了六种[n]MC（n = 13 - 18，n为苯环数），以探索尺寸对结构、电光性质和前沿分子轨道（FMO）的影响。根据二面角（C - C - C - C）分别定义了未扭曲区域和扭曲区域。对于[n]MC（n = 13 - 18），扭曲区域主要分布在七个或八个苯环上。此外，用三种密度泛函方法（BHandHLYP、Cam - B3LYP和M06 - 2X）计算了[n]MC（n = 13 - 18）的极化率（α₀）和第一超极化率（β₀）。结果表明，α₀值随苯环数（n）的增加呈线性增加。值得注意的是，β₀值随苯环数（n）的增加呈锯齿状增加。有趣的是，当n为偶数（14、16和18）时，电子从扭曲区域转移到未扭曲区域，但当n为奇数（13、15和17）时，电子从未扭曲区域转移到扭曲区域。
