Departamento Estrella Campos, Facultad de Química, Universidad de la República, CC 1157, 11800, Montevideo, Uruguay.
J Phys Chem A. 2011 Jan 20;115(2):211-8. doi: 10.1021/jp110100w. Epub 2010 Dec 15.
The UV-vis spectra of the hexanuclear chalcohalide rhenium(III) clusters of formula Re(6)S(8)X(6) (X(-) = Cl(-), Br(-), I(-)) were investigated at the time-dependent density functional theory (TD-DFT) level employing B3LYP, PBE1PBE, and the double-hybrid B2PLYP functional in combination with the LANL2DZ basis set. We were able to reproduce the red shift experimentally observed when the halide changes from chloride to iodide. However, some discrepancies between experimental results and theory were found. First, we did not observe a remarkable dependence of the experimental ill-resolved bands on the solvent. Indeed, similar spectra were obtained taken CH(2)Cl(2) or CH(3)CN as solvents into account. Second, all calculations explained the origin of the band peaked at the low-energy region in contraposition with the one experimentally assumed by R. Long et al. (J. Am. Chem. Soc. 1996, 118, 4603), and theoretically made available by Arratia-Pérez et al. (J. Chem. Phys. 1999, 110, 2529). These authors have proposed a ligand-to-cluster charge transfer (LCCT) for all title complexes. Our findings undoubtedly allow such origin to be discarded. While the HGGA functionals lead to a cluster-to-halide ligand charge transfer (CLCT), an intracluster charge transfer (ICCT) has been considered by employing B2PLYP. This contribution showed B2PLYP in the presence of the solvent to be the best performer in studying the UV-vis spectra of large complexes of rhenium(III) containing the Re-S bond. We strongly recommended the use of the double-hybrid B2PLYP in studying UV-vis spectrum of rhenium complexes of size making the computational cost affordable. We expect that our work stimulates new experimental and theoretical investigations of the title complexes to confirm our assignment.
采用时间依赖密度泛函理论（TD-DFT）在 B3LYP、PBE1PBE 和双杂交 B2PLYP 函数与 LANL2DZ 基组的组合下，研究了化学式为 Re(6)S(8)X(6)（X(-) = Cl(-)、Br(-)、I(-)）的六核硫卤化物铼(III)簇的 UV-vis 光谱。我们能够重现卤化物从氯到碘变化时实验观察到的红移。然而，实验结果和理论之间存在一些差异。首先，我们没有观察到实验中分辨不清的带随溶剂的显著变化。实际上，当考虑 CH(2)Cl(2)或 CH(3)CN 作为溶剂时，得到了相似的光谱。其次，所有的计算都解释了低能区域峰带的起源，与 R. Long 等人（J. Am. Chem. Soc. 1996, 118, 4603）实验假设的起源相反，与 Arratia-Pérez 等人（J. Chem. Phys. 1999, 110, 2529）理论上提供的起源相反。这些作者提出了所有标题配合物的配体到簇电荷转移（LCCT）。我们的发现无疑可以排除这种起源。虽然 HGGA 泛函导致簇到卤化物配体的电荷转移（CLCT），但在 B2PLYP 中考虑了内簇电荷转移（ICCT）。在存在溶剂的情况下，B2PLYP 的这一贡献是研究含有 Re-S 键的铼(III)大配合物 UV-vis 光谱的最佳方法。我们强烈建议在研究尺寸合适的铼配合物的 UV-vis 光谱时使用双杂交 B2PLYP，以使其计算成本可以承受。我们希望我们的工作能够激发对标题配合物的新的实验和理论研究，以确认我们的分配。
