Room-Temperature H<sub>2</sub> Splitting and N<sub>2</sub>-Hydrogenation Induced by a Neutral Lu<sup>II</sup> Complex
Evangelos Papangelis, Luca Demonti, Iker Del Rosal, Angus C. G. Shephard, Laurent Maron, Grégory Nocton, Thomas Simler
Abstract
The direct splitting of H 2 and N 2 molecules is a challenging reaction that is closely related to the Haber–Bosch ammonia synthesis process. Until now, such reactivity has never been observed in the case of molecular lanthanide species. Here, we show that careful selection of the ligand scaffold allows the isolation and characterization of a kinetically stable but highly reactive Lu II complex. This divalent lanthanide species enables direct H 2 splitting at room temperature, an unknown reactivity in lanthanide chemistry, which has been fully corroborated by DFT calculations. In addition, the Lu II complex readily binds N 2, leading to an end-on coordinated diazenido (N 2 ) 2– lanthanide complex. The latter can be hydrogenated under very smooth conditions (ca. 1.2 bar H 2, ambient temperature) to form a unique Lu III –NH 2 complex. Direct N 2 hydrogenation and cleavage are thus accessible using low-valent molecular rare-earth metal complexes.