Luo Xi-Ming, Gong Chun-Hua, Pan Fangfang, Si Yubing, Yuan Jia-Wang, Asad Muhammad, Dong Xi-Yan, Zang Shuang-Quan, Mak Thomas C W
College of Chemistry, Zhengzhou University, 450001, Zhengzhou, China.
College of Chemistry and Chemical Engineering, Henan Polytechnic University, 454003, Jiaozuo, China.
Nat Commun. 2022 Mar 4;13(1):1177. doi: 10.1038/s41467-022-28893-6.
The origins of the chiroptical activities of inorganic nanostructures have perplexed scientists, and deracemization of high-nuclearity metal nanoclusters (NCs) remains challenging. Here, we report a single-crystal structure of Rac-Ag that contains enantiomeric pairs of 70-nuclearity silver clusters with 20 free valence electrons (Ag), and each of these clusters is a doubly truncated tetrahedron with pseudo-T symmetry. A deracemization method using a chiral metal precursor not only stabilizes Ag in solution but also enables monitoring of the gradual enlargement of the electronic circular dichroism (CD) responses and anisotropy factor g. The chiral crystals of R/S-Ag in space group P2 containing a pseudo-T-symmetric enantiomeric NC show significant kernel-based and shell-based CD responses. The small symmetry breaking of T symmetry arising from local distortion of Ag-S motifs and rotation of the apical Ag trigons results in large chiroptical responses. This work opens an avenue to construct chiral medium/large-sized NCs and nanoparticles, which are promising for asymmetric catalysis, nonlinear optics, chiral sensing, and biomedicine.
无机纳米结构的手性光活性起源一直困扰着科学家，而高核金属纳米团簇（NCs）的消旋化仍然具有挑战性。在此，我们报道了一种Rac-Ag的单晶结构，它包含对映体对的70核银簇，具有20个自由价电子（Ag），并且这些簇中的每一个都是具有伪T对称性的双截顶四面体。一种使用手性金属前体的消旋化方法不仅能在溶液中稳定Ag，还能监测电子圆二色性（CD）响应和各向异性因子g的逐渐增大。空间群为P2的R/S-Ag手性晶体包含一个伪T对称对映体NC，显示出显著的基于核和基于壳的CD响应。由Ag-S基序的局部畸变和顶端Ag三角体的旋转引起的T对称性的小破缺导致了大的手性光响应。这项工作为构建手性中/大型NCs和纳米颗粒开辟了一条途径，这在不对称催化、非线性光学、手性传感和生物医学方面具有广阔前景。
