Time-dependent density functional theory calculations have been used to investigate the electronic and optical properties of a nanocluster composed of two directly bonded Au₁₁ subunits, held together by six bidentate diphosphine ligands: 1,8-bis(diphenylphosphino) octane. Three exchange–correlation functionals have been adopted, a general hybrid (PBE0) and two range-separated hybrids (ωB97X and CAM-B3LYP). The results obtained show that the aforementioned properties are significantly different from those of a previously studied Au₁₁-based nanocluster formed by just one single subunit. In particular, charge transfer excitations from the inner metal core to the outer ligands affect most of the UV–visible spectrum and occur for both alkyl and aromatic ligands. This is particularly evident when thiazole molecules are bonded to the gold core: In this case Au → ligand transitions affect also the first HOMO → LUMO excitation. Moreover, the gold core of this Au₂₂ nanocluster has eight under-coordinated Au surface atoms not engaged in bonds with the ligands. No other known organic-protected gold nanocluster has a similar feature. These gold atoms can be considered as potential in situ active sites for catalysis, their catalytic efficiency and selectivity being modulated by charge distribution.

中文翻译：

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DFT和TD-DFT计算公开的Au 22 [1,8-双（二​​苯基膦基）辛烷] 6纳米团簇的电子和光学性质

随时间变化的密度泛函理论计算已用于研究由两个直接键合的Au ₁₁亚基组成的纳米团簇的电子和光学性质，这些Au ₁₁亚基由六个双齿二膦配体（1,8-双（二​​苯基膦基）辛烷）结合在一起。三交换相关函数已被采纳，一般的杂交体（PBE0）和两个范围分隔的杂种（ω B97X和CAM-B3LYP）。所得结果表明，上述性质与先前研究的Au _11的性质显着不同。基纳米簇，仅由一个亚基形成。特别是，从内部金属核到外部配体的电荷转移激发会影响大多数UV可见光谱，并且对于烷基和芳族配体都会发生。当噻唑分子键合到金核上时，这一点尤其明显：在这种情况下，Au→配体跃迁也影响第一个HOMO→LUMO激发。此外，该Au ₂₂纳米簇的金核具有八个未配位的Au表面原子，这些原子未与配体键合。没有其他已知的有机保护金纳米簇具有类似的功能。这些金原子可以被认为是潜在的催化原位活性位，其催化效率和选择性受电荷分布的调节。