Department of Chemistry and Biochemistry, 1039 University Drive, University of Minnesota, Duluth, Minnesota 55812, United States.
J Phys Chem A. 2012 Jul 12;116(27):7364-71. doi: 10.1021/jp304386x. Epub 2012 Jun 29.
Density functional theory (DFT) and time-dependent density functional theory (TDDFT) were used to explain discrepancies in UV-vis and MCD spectra of the metal-free tribenzo[b,g,l]thiopheno[3,4-q]porphyrazine (1), substituted tribenzo[b,g,l]porphyrazine (2), and 2,3-bis(methylcarboxyl)phthalocyanine (3). On the basis of gas-phase and polarized continuum solvation model (PCM) DFT and TDDFT calculations, it was suggested that both NH tautomers contribute to the spectroscopic signature of 1, whereas the Q-band region of 2 and 3 is dominated by a single NH tautomer. For all tested compounds, it was found that the combination of the BP86 exchange-correlation functional, 6-31G(d) basis set, and TDDFT-PCM approach provides the best accuracy in energies of the Q(x)- and Q(y)-bands of the individual NH tautomers as well as correctly describes their relative energy differences, which are important in understanding of experimental spectroscopy of the target systems.
密度泛函理论（DFT）和含时密度泛函理论（TDDFT）被用于解释金属自由三苯并[b，g，l]噻吩并[3，4-q]卟啉（1）、取代三苯并[b，g，l]卟啉（2）和 2，3-双（甲基羧基）酞菁（3）的紫外可见光谱和磁圆二色光谱差异。基于气相和极化连续体溶剂化模型（PCM）DFT 和 TDDFT 计算，提出 1 的光谱特征是由两种 NH 互变异构体贡献的，而 2 和 3 的 Q 带区域则由单个 NH 互变异构体主导。对于所有测试的化合物，发现 BP86 交换相关泛函、6-31G(d)基组和 TDDFT-PCM 方法的组合在单个 NH 互变异构体的 Q(x)-和 Q(y)-带的能量上提供了最佳的准确性，并正确描述了它们的相对能量差异，这对于理解目标系统的实验光谱学非常重要。
