Epoxide C-O bond activation intrigued by waisted flexibility of the Au13Ag12 clusters
image: The rod-shaped Au13Ag12-Py nanocluster has been developed as an efficient catalyst for the cycloaddition reaction, with the TON reaches 3.03×104, and a wide substrate tolerance. The mechanistic investigation indicates that the waisted flexibility is pivotal for the preliminary C-O bond activation of epoxide and the subsequent cyclization.
Credit: Nano research, Anhui University Press
Atomic precise [Au13Ag12(PPh2Py)10Cl8]PF6 supported on activated carbon (AC) achieves a TON of 3.03×104 as a catalyst for epoxide cycloaddition with CO2. The catalyst shows potential applications in sustainable chemistry for synthesizing cyclic carbonates. Mechanistic studies (UV-Vis, XPS, NMR, CV, DFT) reveal that structural flexibility at the waist silver center activates epoxides, while pyridyl nitrogen facilitates CO2 migration, enabling the subsequent cyclization. Structural flexibility of metal nanoclusters is an efficient strategy to activate the substrates, which could hopefully benefit the development of more catalytic systems.
The team published their research article in Nano Research on August 15, 2025.
“CO2 utilization is critical for sustainable chemistry. Atomic precision allows us to pinpoint how nanocluster dynamics enable catalysis. Herein, a series of atomically precise nanoclusters have been prepared, and the [Au13Ag12(PPh2Py)10Cl8]PF6 (Au13Ag12-Py) nanoclusters shows the highest catalytic activity in CO₂-epoxide cycloaddition” said Prof. Haizhu Yu, corresponding authors of the research article, professor in the School of Chemistry and Chemical Engineering at Anhui University.
The team synthesized a series of metal nanocluster catalysts, with different cluster and support components, and found that Au13Ag12-Py loaded on activated carbon (Au13Ag12-Py/AC), outperformed all counterparts. The reaction achieved a turnover number (TON) of 3.03×104 for styrene epoxide cycloaddition with CO2, and is tolerated to epoxides bearing aryl, alkyl, vinyl, ether, or halogen groups.
“Mechanistic studies by means of UV-Vis, XPS, NMR characterizations and DFT simulation revealed the waisted Ag-Cl sites to initiate the activation of epoxides. Pyridyl nitrogen atoms on PPh2Py concentrate CO2 around the cluster, boosting local density of CO2, and enables the subsequent cyclization. We anticipate the structural flexibility of metal nanoclusters could be widely applicable to stimulate catalytic efficiency in more reactions.” Haizhu Yu said.
“Mechanistic studies revealed critical insights through NMR spectroscopy and DFT calculations. 1H NMR showed upfield shifts of pyridine protons in Au13Ag12-Py upon epoxide binding, indicating enhanced electron density at Ag sites. CO2 coordination altered cyclic voltammetry peaks and red-shifted UV-vis absorption (454 nm). DFT simulations identified the rate-determining step to be the cyclization step with a 0.88 eV barrier. The dynamic Ag-Cl bonds at the waisted sites facilitated substrate activation.” Haizhu Yu said.
Other contributors include Ruru Qian, Tingting Jiang, Mengyuan Tu, Qianli Zhang, Ling Chen, Xuejiao Yang, Haizhu Yu, and Manzhou Zhu from Department of Chemistry and Centre for Atomic Engineering of Advanced Materials of Anhui University, Hefei.
This work was supported by the National Natural Science Foundation of China (U23A2090, 21871001), the financial support from Anhui Provincial department of education (2023AH010002). The numerical calculations in this paper have been done on Hefei advanced computing center.
About Nano Research
Nano Research is a peer-reviewed, open access, international and interdisciplinary research journal, sponsored by Tsinghua University and the Chinese Chemical Society, published by Tsinghua University Press on the platform SciOpen. It publishes original high-quality research and significant review articles on all aspects of nanoscience and nanotechnology, ranging from basic aspects of the science of nanoscale materials to practical applications of such materials. After 18 years of development, it has become one of the most influential academic journals in the nano field. Nano Research has published more than 1,000 papers every year from 2022, with its cumulative count surpassing 7,000 articles. In 2024 InCites Journal Citation Reports, its 2024 IF is 9.0 (8.7, 5 years), and it continues to be the Q1 area among the four subject classifications. Nano Research Award, established by Nano Research together with TUP and Springer Nature in 2013, and Nano Research Young Innovators (NR45) Awards, established by Nano Research in 2018, have become international academic awards with global influence.