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 eta(2)-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 H-1 and H-2 NMR spectroscopy as well as DFT calculations and reactivity studies.