Liu Chao, Li Tao, Abroshan Hadi, Li Zhimin, Zhang Chen, Kim Hyung J, Li Gao, Jin Rongchao
State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, 116023, P. R. China.
School of Physical Science and Technology, ShanghaiTech University, Shanghai, 201210, P. R. China.
Nat Commun. 2018 Feb 21;9(1):744. doi: 10.1038/s41467-018-03136-9.
We report the synthesis and crystal structure of a nanocluster composed of 23 silver atoms capped by 8 phosphine and 18 phenylethanethiolate ligands. X-ray crystallographic analysis reveals that the kernel of the Ag nanocluster adopts a helical face-centered cubic structure with C symmetry. The thiolate ligands show two binding patterns with the surface Ag atoms: tri- and tetra-podal types. The tetra-coordination mode of thiolate has not been found in previous Ag nanoclusters. No counter ion (e.g., Na and NO) is found in the single-crystal and the absence of such ions is also confirmed by X-ray photoelectron spectroscopy analysis, indicating electrical neutrality of the nanocluster. Interestingly, the nanocluster has an open shell electronic structure (i.e., 23(Ag 5s)-18(SR) = 5e), as confirmed by electron paramagnetic resonance spectroscopy. Time-dependent density functional theory calculations are performed to correlate the structure and optical absorption/emission spectra of the Ag nanocluster.
我们报道了一种由23个银原子组成的纳米团簇的合成及晶体结构，该纳米团簇由8个膦配体和18个苯乙硫醇盐配体封端。X射线晶体学分析表明，银纳米团簇的内核采用具有C对称性的螺旋面心立方结构。硫醇盐配体与表面银原子呈现两种结合模式：三脚架型和四脚架型。硫醇盐的四配位模式在之前的银纳米团簇中尚未发现。在单晶中未发现抗衡离子（如Na和NO），X射线光电子能谱分析也证实了此类离子的不存在，这表明纳米团簇呈电中性。有趣的是，电子顺磁共振光谱证实该纳米团簇具有开壳层电子结构（即23(Ag 5s)-18(SR) = 5e）。进行了含时密度泛函理论计算，以关联银纳米团簇的结构与光吸收/发射光谱。
