Uranium azide photolysis results in C–H bond activation and provides evidence for a terminal uranium

Abstract

Uranium nitride [U≡N]x is an alternative nuclear fuel that has great potential in the expanding future of nuclear power; however, very little is known about the U≡N functionality. We show, for the first time, that a terminal uranium nitride complex can be generated by photolysis of an azide (U–N=N=N) precursor. The transient U≡N fragment is reactive and undergoes insertion into a ligand C–H bond to generate new N–H and N–C bonds. The mechanism of this unprecedented reaction has been evaluated through computational and spectroscopic studies, which reveal that the photochemical azide activation pathway can be shut down through coordination of the terminal azide ligand to the Lewis acid B(C6F5)3. These studies demonstrate that photochemistry can be a powerful tool for inducing redox transformations for organometallic actinide complexes, and that the terminal uranium nitride fragment is reactive, cleaving strong C–H bonds. The chemistry of the U≡N species is little known, even though solid uranium nitride has been proposed for use as a nuclear fuel. Now, photolysis of a uranium azide complex has been shown to release N2 and generate a transient U≡N fragment that can activate C–H bonds.

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Thomson, R., Cantat, T., Scott, B. et al. Uranium azide photolysis results in C–H bond activation and provides evidence for a terminal uranium nitride. Nature Chem 2, 723–729 (2010). https://doi.org/10.1038/nchem.705

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