金团簇二十面体结构融合过程中其催化活性的演变

doi:10.1016/S1872-2067(20)63659-2

摘要/Abstract

摘要：

近年来, 由有机配体保护的原子精确金属团簇在合成方面已取得了重要进展, 其独特的原子结构对一些化学反应产生独特的催化效果. 原子精确的团簇催化剂明显不同于纳米颗粒催化剂和单原子催化剂, 是一种关联均相和多相的、原子数目确定、尺寸均一、结构精确的新型催化剂. 从原子尺度上精确构筑团簇催化剂, 探究亚纳米尺度的微观结构对催化性能的影响, 为常规催化剂所未能解决的关键科学问题提供解决的机会, 为在分子尺度上揭示催化作用机制以及准确关联催化剂结构与催化性能提供新的研究体系, 具有重要的科学研究意义. 本文设计和使用了三种结构精确的金团簇催化剂, 即Au₂₅(PPh₃)₁₀(SC₂H₄Ph)₅Cl₂, Au₃₈(SC₂H₄Ph)₂₄和Au₂₅(SC₂H₄Ph)₁₈, 分别由二十面体结构的Au₁₃单元通过中心顶点融合、面融合、体相融合形成的(简写为Au_vf、Au_ff和Au_bf), 详细研究了这三个金团簇催化剂在二十面体Au₁₃单元的结构融合过程中, 其催化活性的演变规律. 在催化吡咯烷与O₂反应制备γ-丁内酰胺反应中, 金团簇催化剂的催化活性顺序为Au_bf> Au_ff> Au_vf, 表明这三个金团簇中Au₁₃单元的结构随着点、面、体的融合, 其催化活性随之增加. 同时研究发现, 对于同一个Au团簇催化剂, 其表面硫醇配体的烷基链越短, 其催化活性越高, 这主要是由于短链硫醇分子的空间位阻较小, 吡咯烷分子更容易进入催化剂的金表面, 接触到活性位点, 进行催化反应. 实验表明, 三个团簇金原子均带正电荷, 正价金物种可能是催化吡咯烷与O₂反应的催化活化物种. 研究发现, Au_bf团簇表面的活性位数目高于Au_ff和Au_vf团簇的, 因此Au_bf的催化活性最高; 同时, 团簇表面配体的烷基链越短, 其表面活性位数目也越多, 这也进一步解释了表面硫醇配体的烷基链越短, 其相应的金团簇催化剂的催化活性越高的原因. 吡咯烷与O₂在金团簇上反应的可能路径为O₂在Au活性位上裂解的O原子和吡咯烷β-H转移至Au活性位的β-H反应脱水后形成亚胺, 亚胺经过水解进一步氧化得到产物. 这项研究将为在原子层次上调变金属团簇催化剂的结构进而改变其催化性能提供新的思路, 对精准设计和构筑高效催化剂具有一定的科学指导意义.

关键词: 金团簇, 结构融合, 二十面体结构, 吡咯烷氧化, 活性位点, 催化活性

Abstract:

Atomically precise gold cluster catalysts have emerged as a new frontier in catalysis science, owing to their unexpected catalytic properties. In this work, we explore the evolution of the catalytic activity of clusters formed by the structural fusion of icosahedral Au₁₃ units, namely Au₂₅(SR)₁₈, Au₃₈(SR)₂₄, and Au₂₅(PPh₃)₁₀(SC₂H₄Ph)₅Cl₂, in the oxidation of pyrrolidine to γ-butyrolactam. We demonstrate that the structural fusion of icosahedral Au₁₃units, forming vertex-fused (vf), face-fused (ff), and body-fused (bf) clusters, can induce a decrease in the catalytic activity in the following order: Au_bf > Au_ff > Au_vf. The structural fusion of icosahedral Au₁₃ units in the clusters does not distinguish the adsorption modes of pyrrolidine over the three clusters from each other, but modulates the chemical adsorption capacity and electronic properties of the three clusters, which is likely to be the key reason for the observed changes in catalytic reactivity. Our results are expected to be extendable to study and design atomically defined catalysts with elaborate structural patterns, in order to produce desired products.

Key words: Gold cluster, Structure fusion, Icosahedral unit, Oxidation of pyrrolidine, Active sites, Catalytic activity

杨丹, 祝艳. 金团簇二十面体结构融合过程中其催化活性的演变[J]. 催化学报, 2021, 42(2): 245-250.

Dan Yang, Yan Zhu. Evolution of catalytic activity driven by structural fusion of icosahedral gold cluster cores[J]. Chinese Journal of Catalysis, 2021, 42(2): 245-250.

×
扫码分享

导出引用管理器 EndNote|Ris|BibTeX

链接本文: https://www.cjcatal.com/CN/10.1016/S1872-2067(20)63659-2

https://www.cjcatal.com/CN/Y2021/V42/I2/245

图/表 5

Fig. 1. Structural fusion of icosahedral Au13 units: (a) vertex-fused bi-icosahedral Au25, (b) face-fused bi-icosahedral Au38, and (c) body-fused icosahedral Au25. C and H atoms are omitted for clarity. Color labels: yellow, pink, and magenta: gold; light green: S; dark green: Cl; orange: P. ESI-MS profiles of (d) Auvf, (e) Auff, and (f) Aubf.

Fig. 2. (a) Catalytic oxidation of pyrrolidine over Auvf, Auff, and Aubf catalysts. Reaction conditions: catalyst (100 mg, 2 wt% Au), pyrrolidine (0.44 mmol), O2 (0.4 MPa), n-butanol/H2O (4.5 mL/0.5 mL), 85 °C for different reaction times. (b) Linear dependence of ln(Ct/C0) on reaction time for the oxidation of pyrrolidine over Auvf, Auff, and Aubf catalysts. (c) Arrhenius plot for pyrrolidine oxidation. (d) Conversion of pyrrolidine over Aubf catalysts protected by different thiolate groups (n-butyl mercaptan, 1-octanethiol, and 1-dodecanethiol) (48 h).

Fig. 3. (a) In situ FT-IR spectra of CO adsorbed onto the Auvf, Auff, and Aubf clusters; (b) In situ FT-IR spectra of CO adsorbed onto the Aubf clusters capped by different alkanethiol ligands.

Fig. 4. (a) FT-IR spectra of adsorbed species over the catalysts in the presence of pyrrolidine; (b) XPS profiles of Auvf, Auff, and Aubf clusters.

Scheme 1. Proposed mechanism of pyrrolidine oxidation on gold clusters.

参考文献

[1]	T. Higaki, Q. Li, M. Zhou, S. Zhao, Y. W. Li, S. Li, R. C. Jin, Acc. Chem. Res., 2018,51, 2764-2773.
[2]	B. Nieto-Ortega, T. Bürgi, Acc. Chem. Res., 2018,51, 2811-2819.
[3]	P. X. Liu, R. X. Qin, G. Fu, N. F. Zheng, J. Am. Chem. Soc., 2017,139, 2122-2131.
[4]	I. Chakraborty, T. Pradeep, Chem. Rev., 2017,117, 8208-8271.
[5]	S. B. Tian, L. W. Liao, J. Y. Yuan, C. H. Yao, J. S. Chen, J. L. Yang, Z. K. Wu, Chem. Commun., 2016,52, 9873-9876.
[6]	Z. Lei, Q. M. Wang, Coord. Chem. Rev., 2019,378, 382-394.
[7]	R. Ishida, S. Arii, W. Kurashige, S. Yamazoe, K. Koyasu, Y. Negishi, T. Tsukuda, Chin. J. Catal., 2016,37, 1656-1661.
[8]	H. J. Chen, C. Liu, M. Wang, C. F. Zhang, G. Li, F. Wang, Chin. J. Catal., 2016,37, 1787-1793.
[9]	Y. Y. Liu, X. Q. Chai, X. Cai, M. Y. Chen, R. C. Jin, W. D. Ding, Y. Zhu, Angew. Chem. Int. Ed., 2018,57, 9775-9779.
[10]	Y. Zhu, H. F. Qian, A. Das, R. C. Jin, Chin. J. Catal., 2011,32, 1149-1155.
[11]	Y. W. Zhang, P. Song, T. Chen, X. D. Liu, T. Chen, Z. M. Wu, Y. Wang, J. P. Xie, W. Lin, Proc. Natl. Acad. Sci. USA, 2018,115, 10588-10593.
[12]	Y. Zhu, H. F. Qian, B. A. Drake, R. C. Jin, Angew. Chem. Int. Ed., 2010,49, 1295-1301.
[13]	Y. Tan, H. Liu, X. Y. Liu, A. Q. Wang, C. J. Liu, T. Zhang, Chin. J. Catal., 2018,39, 929-936.
[14]	J. Xu, M. Chen, Y. Zhu, Chem. Eur. J., 2019,25, 9185-9190.
[15]	S. H. Xie, H. Tsunoyama, W. Kurashige, Y. Negishi, T. Tsukuda, ACS Catal., 2012,2, 1519-1523.
[16]	Z. B. Gan, N. Xia, Z. K. Wu, Acc. Chem. Res., 2018,51, 2774-2783.
[17]	Z. M. Li, X. J. Yang, C. Liu, J. Wang, G. Li, Prog. Nat. Sci., 2016,26, 477-482.
[18]	K. Kwak, Q. Tang, M. Kim, D. E. Jiang, D. Lee, J. Am. Chem. Soc., 2015,137, 10833-10840.
[19]	M. Z. Zhu, E. Lanni, N. Garg, M. E. Bier, R. C. Jin, J. Am. Chem. Soc., 2008,130, 1138-1139.
[20]	H. F. Qian, Y. Zhu, R. C. Jin, ACS Nano., 2009,3, 3795-3803.
[21]	H. F. Qian, M. Z. Zhu, E. Lanni, Y. Zhu, M. E. Bier, R. C. Jin, J. Phys. Chem. C, 2009,113, 17600-17603.
[22]	A. Abad, P. Concepcion, A. Corma, H. García, Angew. Chem. Int. Ed., 2005,44, 4066-4069.
[23]	A. Shivhare, S. J. Ambrose, H. Zhang, R. W. Purves, R. W. J. Scott, Chem. Commun., 2013,49, 276-278.
[24]	Z. Wu, D. E. Jiang, A. K. P. Mann, D. R. Mullins, Z. Qiao, L. F. Allard, C. Zeng, R. Jin, S. H. Overbury, J. Am. Chem. Soc., 2014,136, 6111-6122.
[25]	Z. L. Wu, D. E. Jiang, A. K. P. Mann, D. R. Mullins, Z. A. Qiao, L. F. Allard, C. J. Zeng, R. C. Jin, S. H. Overbury, Nano Lett., 2016,16, 6560-6567.
[26]	F. Boccuzzi, A. Chiorino, M. Manzoli, P. Lu, T. Akita, S. Ichikawa, M. Haruta, J. Catal., 2001,202, 256-267.
[27]	Q. L. Wang, K. Q. Shen, M.Y. Chen, Y. Zhu, Nanoscale, 2019,11, 13767-13772.