Catalytic visible light-driven alkane dehydrogenation by a di-uranyl germanotungstate
Elias Tanuhadi1,2, Gabriel Herrera1,2, Cambell S Conour1,2
1Dept of Chemistry, University of California Berkeley Berkeley CA 94720 USA pla@berkeley.edu elias.tanuhadi@berkeley.edu.
Chemical Science
|July 3, 2026
Summary
A novel dinuclear uranyl complex enables photocatalytic dehydrogenation of cycloalkanes to alkenes using visible light. This breakthrough advances hydrocarbon upgrading by efficiently cleaving inert C-H bonds under ambient conditions.
Area of Science:
- Inorganic Chemistry
- Photocatalysis
- Sustainable Chemistry
Background:
- Dehydrogenation of alkanes to alkenes is crucial for upgrading hydrocarbons.
- Cleaving inert C(sp3)-H bonds selectively and without overoxidation remains a significant challenge.
- Existing photocatalysts often lack efficiency or require harsh conditions.
Purpose of the Study:
- To develop a novel photocatalyst for efficient dehydrogenation of unactivated cycloalkanes.
- To investigate a cooperative dinuclear uranyl complex for visible-light-driven C-H bond activation.
- To explore the mechanism of double hydrogen atom abstraction in photocatalytic dehydrogenation.
Main Methods:
- Synthesis of a dinuclear uranyl complex, [NBu4]8[(UO2)2(GeW10O34(µ2-OH)2)2]·(CH3)2CO (1), supported by a germanotungstate.
- Photocatalytic dehydrogenation reactions using 1 mol% of complex 1 under visible light (427 nm).
- Utilized sacrificial oxidants like potassium persulfate ([S2O8]2-) or chloranil (C6Cl4O2) in acetonitrile.
- Mechanistic studies involving deuterated substrates to probe hydrogen atom transfer pathways.
Main Results:
- Complex 1 efficiently converted cyclooctane to cyclooctene (TON 44) and 9,10-dihydrophenanthrene to phenanthrene (TON 73).
- The dinuclear uranyl complex demonstrated superior activity compared to mononuclear uranyl nitrate.
- A direct hydrogen atom transfer (d-HAT) mechanism involving two sequential hydrogen atom abstractions (HAA) was proposed.
- Stereochemical analysis of deuterated substrates supported the proposed d-HAT mechanism with face-selective HAA.
Conclusions:
- The cooperative dinuclear uranyl complex enables efficient photocatalytic dehydrogenation of unactivated cycloalkanes under visible light.
- This system offers a promising strategy for upgrading abundant hydrocarbons via selective C-H bond functionalization.
- The preorganization of two uranyl centers is key to achieving double hydrogen atom abstraction and high catalytic activity.
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