マンガンが新たな燃料電池触媒候補に（Manganese Gets Its Moment as a Potential Fuel Cell Catalyst）

2026-01-06 イェール大学

＜関連情報＞

• https://news.yale.edu/2026/01/06/manganese-gets-its-moment-potential-fuel-cell-catalyst
• https://www.cell.com/chem/abstract/S2451-9294(25)00424-3

半不安定配位子を有するピンサー配位マンガン錯体を用いたCO2水素化の生産性と安定性の向上 Improving productivity and stability for CO2 hydrogenation by using pincer-ligated Mn complexes with hemilabile ligands

Justin C. Wedal ∙ Kyler B. Virtue ∙ Wesley H. Bernskoetter ∙ Nilay Hazari ∙ Brandon Q. Mercado ∙ Nicole Piekut
Chem  Published:January 5, 2026
DOI:https://doi.org/10.1016/j.chempr.2025.102833

Graphical abstract

The bigger picture

Formic acid is currently produced on an industrial scale from fossil-fuel-derived feedstocks for use as a preservative, antibacterial agent, and tanning agent. Further, formic acid could be a source of hydrogen in fuel cells. Given the environmental issues associated with using feedstocks from fossil fuels, a more attractive synthesis of formic acid would use renewable feedstocks, such as CO₂ and H₂ from water electrolysis using electricity generated from sustainable sources. Many transition-metal catalysts have been described for the conversion of CO₂ and H₂ to formic acid (or formate). The most active and stable catalysts are typically based on precious-metal catalysts, which are expensive, unsustainable, and highly toxic. Therefore, the development of catalysts based on inexpensive, abundant, and more sustainable first-row transition metals would be beneficial.

Current first-row transition-metal catalysts for CO₂ hydrogenation and related transformations often suffer from rapid decomposition that limits turnover numbers, yields, and lifetimes. Consequently, preventing deactivation pathways is a major challenge for the field. In this work, Mn catalysts with ancillary ligands designed to prevent decomposition are prepared. A donor that can reversibly bind to the catalyst is incorporated onto the main supporting ligand. Tuning the binding strength of the hemilabile donor produced significantly longer catalyst lifetimes than reported for previous catalysts. The achieved turnover frequencies and turnover numbers exceeded those of most state-of-the-art first-row or precious-metal catalysts. Overall, this work elucidates design principles that can be broadly applied to many other catalytic transformations and catalysts. Thus, its impact is likely to stretch well beyond CO₂ hydrogenation to formate.

Highlights

• Preparation of pincer ligands incorporating an additional hemilabile donor
• Synthesis of pincer-ligated Mn catalysts for CO₂ hydrogenation to formate
• Catalysts give improved turnover numbers, turnover frequencies, and lifetimes
• Mechanistic studies describe how the hemilabile donor affects catalytic performance

Summary

Pincer ligands are widely used to support transition-metal catalysts, but first-row systems often deactivate too quickly for widespread use. Here, pincer ligands bearing an additional hemilabile donor were designed to stabilize Mn catalysts for CO₂ hydrogenation to formate. Ligands of the type (RCH₂CH₂)N(CH₂CH₂PⁱPr₂)₂ (^iPrPN^RP; R = OMe, CH₂OMe, NMe₂, PⁱPr₂) were synthesized and coordinated to Mn to form complexes of the type (^iPrPN^RP)Mn(CO)₂H. Their performance was compared with that of {MeN(CH₂CH₂PⁱPr₂)₂}Mn(CO)₂H, which lacks a pendant donor. The pendant donor identity and arm length strongly influenced catalytic activity, but all pendant-arm-containing systems extended catalyst lifetime. Notably, (^iPrPN^CH2OMeP)Mn(CO)₂H achieved turnover frequencies of 158,000 h⁻¹ and turnover numbers of 838,000, exceeding most state-of-the-art catalysts. Mechanistic studies revealed that hemilabile coordination enhances stability by avoiding deactivation, although excessive binding can lead to inactive states. This work demonstrates that hemilabile donors dramatically improve pincer-based Mn catalysts and provides design principles for broader applications.