Issue 43, 2023

Cooperative dihydrogen activation with unsupported uranium–metal bonds and characterization of a terminal U(iv) hydride

Abstract

Cooperative chemistry between two or more metal centres can show enhanced reactivity compared to the monometallic fragments. Given the paucity of actinide–metal bonds, especially those with group 13, we targeted uranium(III)–aluminum(I) and –gallium(I) complexes as we envisioned the low-valent oxidation state of both metals would lead to novel, cooperative reactivity. Herein, we report the molecular structure of [(C5Me5)2(MesO)U-E(C5Me5)], E = Al, Ga, Mes = 2,4,6-Me3C6H2, and their reactivity with dihydrogen. The reaction of H2 with the U(III)–Al(I) complex affords a trihydroaluminate complex, [(C5Me5)2(MesO)U(μ2-(H)3)–Al(C5Me5)] through a formal three-electron metal-based reduction, with concomitant formation of a terminal U(IV) hydride, [(C5Me5)2(MesO)U(H)]. Noteworthy is that neither U(III) complexes nor [(C5Me5)Al]4 are capable of reducing dihydrogen on their own. To make the terminal hydride in higher yields, the reaction of [(C5Me5)2(MesO)U(THF)] with half an equivalent of diethylzinc generates [(C5Me5)2(MesO)U(CH2CH3)] or treatment of [(C5Me5)2U(I)(Me)] with KOMes forms [(C5Me5)2(MesO)U(CH3)], which followed by hydrogenation with either complex cleanly affords [(C5Me5)2(MesO)U(H)]. All complexes have been characterized by spectroscopic and structural methods and are rare examples of cooperative chemistry in f element chemistry, dihydrogen activation, and stable, terminal ethyl and hydride compounds with an f element.

Graphical abstract: Cooperative dihydrogen activation with unsupported uranium–metal bonds and characterization of a terminal U(iv) hydride

Supplementary files

Article information

Article type
Edge Article
Submitted
14 Sep 2023
Accepted
13 Oct 2023
First published
16 Oct 2023
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2023,14, 12255-12263

Cooperative dihydrogen activation with unsupported uranium–metal bonds and characterization of a terminal U(IV) hydride

R. J. Ward, P. Rungthanaphatsophon, P. Huang, S. P. Kelley and J. R. Walensky, Chem. Sci., 2023, 14, 12255 DOI: 10.1039/D3SC04857H

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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