Departament d'Enginyeria Quíímica, EUETII, Universitat Politècnica de Catalunya, Pça. Rei 15, 08700 Igualada, Spain.
J Phys Chem B. 2009 Nov 19;113(46):15196-203. doi: 10.1021/jp9070086.
Quantum chemical methods have been applied on model oligomers of poly(thiaheterohelicene)s to investigate the structural and electronic properties of these systems. Specifically, the properties of the helical structures found for poly(heterohelicene) and poly(methyl-sulfonium), which were calculated using density functional theory calculations, are in good agreement with available experimental data. The geometrical parameters obtained for poly(methyl-sulfonium) reflect the enlargement of the inner carbon-carbon bond lengths at the thiophene rings, which are those closer to the helical screw axes, and lead to reduce their aromaticity of such heterocycles. On this basis, a relationship between the aromaticity and the lowest pi-pi* transition energy has been established. Finally, the lowest pi-pi* transitions have been extrapolated for infinite polymer chains of poly(heterohelicene) and poly(methyl-sulfonium) using different theoretical approaches.
量子化学方法已被应用于聚（杂噻吩并[3,2-b]噻吩）的模型低聚物，以研究这些体系的结构和电子性质。具体来说，使用密度泛函理论计算计算得到的聚（杂噻吩并[3,2-b]噻吩）和聚（甲基-亚砜）的螺旋结构的性质与可用的实验数据非常吻合。聚（甲基-亚砜）的几何参数反映了噻吩环上靠近螺旋螺旋轴的内碳-碳键长度的增大，从而降低了这些杂环的芳香性。在此基础上，建立了芳香性与最低π-π跃迁能之间的关系。最后，使用不同的理论方法对聚（杂噻吩并[3,2-b]噻吩）和聚（甲基-亚砜）的无限聚合物链的最低π-π跃迁进行了外推。
