Reversible C−C Coupling in a Uranium Biheterocyclic Complex

The C−C coupling of two molecules of 1-methylbenzimidazole was effected by a neutral uranium dibenzyl complex supported by a ferrocene 1,1′-diamide ligand. The transformation involves the C−H activation of two heterocycles and the coupling of one η2-N,C-imidazolyl fragment with a coordinated 1-methylbenzimidazole ligand. The solid-state structure of this product was studied by both single-crystal and powder X-ray diffraction methods and confirms the formation of the biheterocyclic moiety. In solution, the C−C coupling event was found to be reversible, as assessed by variable-temperature 1H and 2H NMR spectroscopy as well as DFT calculations and reactivity studies.