Redox-active inverse crowns for small molecule activation

Maurer J, Klerner L, Mai J, Stecher H, Thum S, Morasch M, Langer J, Harder S (2025)

Publication Type: Journal article

Publication year: 2025

Journal

DOI: 10.1038/s41557-024-01724-5

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 Mg⁰ 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 N2O2²⁻ 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. (Figure presented.)

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How to cite

APA:

Maurer, J., Klerner, L., Mai, J., Stecher, H., Thum, S., Morasch, M.,... Harder, S. (2025). Redox-active inverse crowns for small molecule activation. Nature Chemistry. https://doi.org/10.1038/s41557-024-01724-5

MLA:

Maurer, Johannes, et al. "Redox-active inverse crowns for small molecule activation." Nature Chemistry (2025).

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