Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, China.
J Mol Graph Model. 2012 Mar;33:26-34. doi: 10.1016/j.jmgm.2011.10.008. Epub 2011 Nov 3.
The vertical excitation energies of tetrathiafulvalene (TTF)-annulated zinc porphyrazine (ZnPzTTF) were investigated using time-dependent density functional theory (TDDFT) calculations and compared to the experimental UV-vis spectra. To examine the effects of the aza substitutions and TTF groups on the molecular properties, zinc complexes of porphyrin (ZnP), porphyrazine (ZnPz) and tetraTTF-annulated porphyrin (ZnPTTF) were also selected for comparison. It was shown that numerous electronic transitions with TTF-to-porphyrin or porphyrazine charge transfer character exist and the Q band of ZnPzTTF is dominated by TTF-to-porphyrazine charge transfer transition mixed with porphyrazine core unit itself except for classic porphyrazine π→π* transitions. The Q band of ZnPzTTF mixes with other configurations, which breaks down the Gouterman's classic four-orbital model for the spectral interpretation. The data suggest that TDDFT/SAOP performs best for Q and B bands of ZnPzTTF with the maximum error in excitation energy being 0.17 eV. The CAM-B3LYP, ωB97XD and M06-2X calculations qualitatively predict that the low-lying electronic transitions of ZnPzTTF with TTF-to-porphyrazine charge transfer character located below the Q band. The broad and intense red-shifted Q band suggests that ZnPzTTF can be a candidate for dye-sensitized solar cells.
用含时密度泛函理论（TDDFT）计算研究了四硫富瓦烯（TTF）环化锌卟啉（ZnPzTTF）的垂直激发能，并与实验紫外可见光谱进行了比较。为了考察氮杂取代和 TTF 基团对分子性质的影响，还选择了卟啉（ZnP）、卟嗪（ZnPz）和四 TTf 环化卟啉（ZnPTTF）的锌配合物进行比较。结果表明，存在许多具有 TTF 到卟啉或卟嗪电荷转移特性的电子跃迁，并且 ZnPzTTF 的 Q 带主要由 TTF 到卟嗪的电荷转移跃迁与卟嗪核心单元本身混合组成，除了经典的卟嗪π→π*跃迁。ZnPzTTF 的 Q 带与其他构型混合，破坏了光谱解释的 Gouterman 经典四轨道模型。数据表明，TDDFT/SAOP 对 ZnPzTTF 的 Q 和 B 带的表现最好，激发能的最大误差为 0.17 eV。CAM-B3LYP、ωB97XD 和 M06-2X 计算定性预测了 ZnPzTTF 中具有 TTF 到卟嗪电荷转移特性的低能电子跃迁位于 Q 带以下。宽而强烈的红移 Q 带表明 ZnPzTTF 可以成为染料敏化太阳能电池的候选材料。
