德国埃尔朗根-纽伦堡弗里德里希-亚历山大大学Sjoerd Harder团队近日取得一项新成果。经过不懈努力，他们开发出用于小分子活化的氧化还原活性逆冠。该项研究成果发表在2025年2月17日出版的《自然-化学》上。

本文报道了一种具有Na⁺阳离子和氧化还原活性MgO中心的预组装逆冠的合成。还原N₂O，然后释放N₂，然后包封O₂演示其减少和捕获功能。计算表明，这个基本无障碍的过程涉及一种罕见的N₂O₂钻石，镶嵌在金属循环中。逆冠可以适应更大的阴离子，如N₂O₂^2-通过一个包括环扩张的自我重组过程。具有氧化还原活性的反冠结合了强还原剂的优点和金属阳离子环提供的阴离子稳定特性，从而具有高反应活性和选择性。

据了解，环冠醚结合金属阳离子形成主客体配合物。不太为人所知的逆冠是包裹阴离子实体的金属阳离子环，可以进行多次去质子化反应，通常具有非互选择性。在去质子化反应中，金属阳离子在带多重电荷的碳原子周围的自组装循环是这种反应性的驱动力。

附：英文原文

Title: Redox-active inverse crowns for small molecule activation

Author: Maurer, Johannes, Klerner, Lukas, Mai, Jonathan, Stecher, Hannah, Thum, Stefan, Morasch, Michael, Langer, Jens, Harder, Sjoerd

Issue&Volume: 2025-02-17

Abstract: Cyclic crown ethers bind metal cations to form host–guest complexes. Lesser-known inverse crowns are rings of metal cations that encapsulate anionic entities, enabling multiple deprotonation reactions, often with unusual selectivity. Self-assembly of a cycle of metal cations around the multiply charged carbanion during the deprotonation reaction is the driving force for this reactivity. Here we report the synthesis of a pre-assembled inverse crown featuring Na⁺ cations and a redox-active MgO centre. Reduction of N₂O followed by N₂ release and subsequent encapsulation of O₂ demonstrates its reduce-and-capture functionality. Calculations reveal that this essentially barrier-free process involves a rare N₂O₂ dianion, embedded in the metalla-cycle. The inverse crown can adapt itself for binding larger anions like N₂O₂^2- through a self-reorganization process involving ring expansion. The redox-active inverse crown combines the advantages of a strong reducing agent with anion stabilizing properties provided by the ring of metal cations, leading to high reactivity and selectivity.

DOI: 10.1038/s41557-024-01724-5

Source: https://www.nature.com/articles/s41557-024-01724-5