超分子配位子設計による金ナノクラスタ～触媒の高活性化～

2025-07-22 京都大学

金25核の分子状金ナノクラスターに、ペプチドデンドロン型超分子配位子を導入することで、表面に超分子反応場が形成され、触媒活性が従来比40倍に向上した。これにより、100日以上の長期安定性と80万回を超える高い触媒回転数を実現。これまで配位子は主に構造安定化に使われていたが、本研究は配位子設計による触媒性能の飛躍的向上を示し、高活性・高耐久な次世代金属ナノクラスター触媒開発への道を開いた。

本研究の概要図：超分子配位子設計による高活性金ナノクラスター触媒の模式図

＜関連情報＞

超分子リガンドエンジニアリングによる原子レベルで精密なチオレート保護金ナノクラスターの触媒反応の促進 Accelerated Catalysis of Atomically Precise Thiolate-Protected Gold Nanoclusters by Supramolecular Ligand Engineering

Kyosuke Ueda,Ryohei Saito,Kenta Iseri,Sota Sekiya,Masaharu Nakamura,and Katsuhiro Isozaki
ACS Catalysis Published: July 9, 2025
DOI:https://doi.org/10.1021/acscatal.5c01743

Abstract

We herein report the reaction acceleration effect of a supramolecular reaction field constructed with dendritic peptide thiolate ligands on the Au₂₅ nanocluster toward the catalytic cyclization of alkynoic acids. A remarkable reaction acceleration was achieved by peptide dendron thiolate ligands, which was 40 times greater than that achieved by simple alkyl thiolate ligands. Association experiments with ¹H NMR spectroscopy revealed that the unprecedented intermolecular hydrogen bonds between peptide dendron ligands and ammonium salts of alkynoic acids play a critical role in the reaction acceleration effect. The high stability of the nanocluster catalyst bearing the supramolecular reaction field was also represented by the turnover number over 820,000 in this catalytic reaction. Mechanistic investigations revealed the involvement of pi-coordinated alkynes and subsequent vinyl–Au intermediates. DFT calculations support the possible reaction pathway, including both the anionic and neutral forms of the nanocluster as the catalyst. Our findings demonstrate the usefulness of the supramolecular ligand approach for metallic nanocluster catalysis, enabling enhanced catalytic efficiency and selectivity toward various organic transformations.