Pentanuclear Scaffold: A Molecular Platform for Small-Molecule ConversionsClick to copy article linkArticle link copied!
- Mio KondoMio KondoDivision of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, JapanMore by Mio Kondo
- Shigeyuki Masaoka*Shigeyuki Masaoka*Email: [email protected]Division of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, JapanMore by Shigeyuki Masaoka
Abstract

Conspectus
Small-molecule conversions involving multielectron transfer processes enable the conversion of earth-abundant materials into valuable chemicals and are regarded as a solution for environmental and energy shortage problems. In this context, the development of artificial catalysts that promote these reactions is an important research target. In nature, metalloenzymes that contain multinuclear metal complexes as active sites are known to efficiently catalyze reactions under mild conditions. Therefore, using multinuclear metal complexes as artificial catalysts can be an attractive strategy for small-molecule conversions involving multielectron transfer processes. However, multinuclear-metal-complex-based catalysts for these reactions have not been well established. In this Account, we describe our recent advances in the development of multinuclear metal complexes as catalysts for small-molecule conversion, mainly focusing on water oxidation. As small-molecule conversions involving multielectron transfer processes consists of two essential processes, (1) the transfer of multiple electrons and (2) the formation/cleavage of covalent bond(s), catalysts for these reactions should facilitate both steps. Therefore, we assumed that the assembly of redox-active metal ions and the cooperative effect of neighboring coordinatively unsaturated metal ions can promote these processes. On the basis of this assumption, we employed a pentanuclear metal complex as a molecular scaffold for the catalyst. The scaffold has a pentanuclear structure with quasi-D3 symmetry and consists of a [M3(μ3-X)] core (X = O2– or OH–) wrapped by two [M(μ-bpp)3] units (Hbpp = 3,5-bis(2-pyridyl)pyrazole). The metal ions in the triangular core are coordinatively unsaturated, whereas the metal ions at the apical positions are coordinatively saturated. In other words, the pentanuclear scaffold possesses multiple redox-active centers and coordinatively unsaturated sites. It should also be noted that the electron transfer ability of the complex changes dramatically depending on the identity of the constituent metal ions. The iron derivative of the pentanuclear scaffold was found to serve as an electrocatalyst for water oxidation (2H2O → O2 + 4e– + 4H+) with a high reaction rate and excellent robustness. The substitution of metal ions in the pentanuclear scaffold to cobalt ions resulted in the development of a catalyst for CO2 reduction. Furthermore, we investigated the effect of substituents on the ligands of the pentanuclear iron complex and succeeded in precisely manipulating the electron transfer possess. These results clearly demonstrate that the pentanuclear scaffold is an attractive platform for catalysts for small-molecule conversions. Additionally, the intrinsic features of the multinuclear catalytic system, which are totally different from those of conventional mononuclear-metal-complex-based catalysts, are disclosed. In reactions mediated by multinuclear complexes, the multinuclear core can initially accumulate the charge required for catalysis to reach the catalytically active state. Subsequently, the catalyst in the active state reacts with the substrate, initiating electron transfer to the substrate and rearrangement of covalent bonds in the substrate to afford the product. In such a mechanism, the desired number of electrons can be transferred to the substrates in an on-demand fashion, and the formation of undesired chemical species in the targeted catalysis may be prevented. This feature of multinuclear-metal-complex-based catalysts will achieve demanding small-molecule conversions with a high reaction rate, selectivity, and durability.
Cited By
Smart citations by scite.ai include citation statements extracted from the full text of the citing article. The number of the statements may be higher than the number of citations provided by ACS Publications if one paper cites another multiple times or lower if scite has not yet processed some of the citing articles.
This article is cited by 21 publications.
- Sen Lu, Zhiguo Wang, Zhikai Gao, Tiren Peng, Pei Song, Zepeng Jia, Yuhang Zhou, Hong Cui, Weizhi Tian, Rong Feng, Lingxia Jin, Hongkuan Yuan. Modulation of Hydrogen Evolution Reaction Performance of MXenes by Doped Transition Metals: Comprehensive Exploration of High-Throughput Computing and Machine Learning. ACS Applied Materials & Interfaces 2025, 17
(16)
, 23795-23808. https://doi.org/10.1021/acsami.4c21255
- Yonggui Zhao, Devi Prasad Adiyeri Saseendran, Chong Huang, Carlos A. Triana, Walker R. Marks, Hang Chen, Han Zhao, Greta R. Patzke. Oxygen Evolution/Reduction Reaction Catalysts: From In Situ Monitoring and Reaction Mechanisms to Rational Design. Chemical Reviews 2023, 123
(9)
, 6257-6358. https://doi.org/10.1021/acs.chemrev.2c00515
- Xialiang Li, Haitao Lei, Lisi Xie, Ni Wang, Wei Zhang, Rui Cao. Metalloporphyrins as Catalytic Models for Studying Hydrogen and Oxygen Evolution and Oxygen Reduction Reactions. Accounts of Chemical Research 2022, 55
(6)
, 878-892. https://doi.org/10.1021/acs.accounts.1c00753
- Sikai Wang, Zhimeng Wang, Haitao Lei, Xue-Peng Zhang, Xialiang Li, Rui Cao. Molecular electrocatalysis: Metalloporphyrins for hydrogen evolution and oxygen evolution and oxygen reduction reactions. Chinese Science Bulletin 2024, 69
(34)
, 4983-4998. https://doi.org/10.1360/TB-2024-0942
- Hitoshi Izu, Mio Kondo, Masaya Okamura, Misa Tomoda, Sze Koon Lee, Takuya Akai, Vijayendran K. K. Praneeth, Mari Kanaike, Satoshi Kawata, Shigeyuki Masaoka. Precise Manipulation of Electron Transfers in Clustered Five Redox Sites. Angewandte Chemie International Edition 2024, 63
(47)
https://doi.org/10.1002/anie.202408514
- Hitoshi Izu, Mio Kondo, Masaya Okamura, Misa Tomoda, Sze Koon Lee, Takuya Akai, Vijayendran K. K. Praneeth, Mari Kanaike, Satoshi Kawata, Shigeyuki Masaoka. Precise Manipulation of Electron Transfers in Clustered Five Redox Sites. Angewandte Chemie 2024, 136
(47)
https://doi.org/10.1002/ange.202408514
- Yosuke Hosoya, Hiroki Yoshikawa, Arata Tsukamoto, Kosuke Sugawa, Joe Otsuki. Alterations in magnetic properties of crystals of trinuclear copper complexes: isolated entities versus one-dimensional chains. Chemistry Letters 2024, 53
(2)
https://doi.org/10.1093/chemle/upad033
- Roman Ezhov, Gabriel Bury, Olga Maximova, Elliot Daniel Grant, Mio Kondo, Shigeyuki Masaoka, Yulia Pushkar. Pentanuclear iron complex for water oxidation: Spectroscopic analysis of reactive intermediates in solution and catalyst immobilization into the MOF-based photoanode. Journal of Catalysis 2024, 429 , 115230. https://doi.org/10.1016/j.jcat.2023.115230
- Junyang Liu, Manar M. Shoshani, Kethya Sum, Samuel A. Johnson. Breaking bonds and breaking rules: inert-bond activation by [(
i
Pr
3
P)Ni]
5
H
4
and catalytic stereospecific norbornene dimerization. Chemical Communications 2023, 59
(24)
, 3542-3545. https://doi.org/10.1039/D2CC06681E
- Misa Tomoda, Mio Kondo, Hitoshi Izu, Shigeyuki Masaoka. Brønsted Acid/Base Site Isolated in a Pentanuclear Scaffold. Chemistry – A European Journal 2023, 29
(7)
https://doi.org/10.1002/chem.202203253
- Mio Kondo, Shigeyuki Masaoka. Function-Integrated Catalytic Systems for Small-Molecule Conversion: Advances and Perspectives. Journal of Synthetic Organic Chemistry, Japan 2022, 80
(11)
, 1055-1064. https://doi.org/10.5059/yukigoseikyokaishi.80.1055
- Haitao Lei, Qingxin Zhang, Zuozhong Liang, Hongbo Guo, Yabo Wang, Haoyuan Lv, Xialiang Li, Wei Zhang, Ulf‐Peter Apfel, Rui Cao. Metal‐Corrole‐Based Porous Organic Polymers for Electrocatalytic Oxygen Reduction and Evolution Reactions. Angewandte Chemie 2022, 134
(24)
https://doi.org/10.1002/ange.202201104
- Haitao Lei, Qingxin Zhang, Zuozhong Liang, Hongbo Guo, Yabo Wang, Haoyuan Lv, Xialiang Li, Wei Zhang, Ulf‐Peter Apfel, Rui Cao. Metal‐Corrole‐Based Porous Organic Polymers for Electrocatalytic Oxygen Reduction and Evolution Reactions. Angewandte Chemie International Edition 2022, 61
(24)
https://doi.org/10.1002/anie.202201104
- Shangxing Li, Hikaru Iwami, Mio Kondo, Shigeyuki Masaoka. Electrochemical Polymerization of a Carbazole‐Tethered Cobalt Phthalocyanine for Electrocatalytic Water Oxidation. ChemNanoMat 2022, 8
(6)
https://doi.org/10.1002/cnma.202200028
- Wan‐Chi Hsu, Yu‐Heng Wang. Homogeneous Water Oxidation Catalyzed by First‐Row Transition Metal Complexes: Unveiling the Relationship between Turnover Frequency and Reaction Overpotential. ChemSusChem 2022, 15
(5)
https://doi.org/10.1002/cssc.202102378
- Hikaru Iwami, Mio Kondo, Shigeyuki Masaoka. Fabrication of a Function‐Integrated Water Oxidation Catalyst through the Electrochemical Polymerization of Ruthenium Complexes. ChemElectroChem 2022, 9
(2)
https://doi.org/10.1002/celc.202101363
- Hua Yang, Jianmin Dou, You Song. Metallacrown-Based Catalysts for Water Oxidation and CO2 Conversion. 2022, 317-332. https://doi.org/10.1007/978-3-031-08576-5_8
- Mio Kondo, Hayato Tatewaki, Shigeyuki Masaoka. Design of molecular water oxidation catalysts with earth-abundant metal ions. Chemical Society Reviews 2021, 50
(12)
, 6790-6831. https://doi.org/10.1039/D0CS01442G
- Hikaru Iwami, Masaya Okamura, Mio Kondo, Shigeyuki Masaoka. Electrochemical Polymerization Provides a Function‐Integrated System for Water Oxidation. Angewandte Chemie 2021, 133
(11)
, 6030-6034. https://doi.org/10.1002/ange.202015174
- Hikaru Iwami, Masaya Okamura, Mio Kondo, Shigeyuki Masaoka. Electrochemical Polymerization Provides a Function‐Integrated System for Water Oxidation. Angewandte Chemie International Edition 2021, 60
(11)
, 5965-5969. https://doi.org/10.1002/anie.202015174
- Ionel Haiduc. Inverse Coordination Complexes: Oxygen as Coordination Center. 2021, 66-120. https://doi.org/10.1016/B978-0-08-102688-5.00062-3
Article Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.
Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.
The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated.