Selective Catalytic Reduction of N to NH by a Simple Fe Complex.

The catalytic fixation of N by molecular Fe compounds is a rapidly developing field, yet thus far few complexes can effect this transformation, and none are selective for NH production. Herein we report that the simple Fe(0) complex Fe(EtPCHCHPEt)(N) (1) is an efficient catalyst for the selective conversion of N (>25 molecules N fixed) into NH, attendant with the production of ca. one molecule of NH. Notably, the reductant (CoCp*) and acid (PhNHOTf) used are considerably weaker than conventional chemical H and e sources used in previous demonstrations of N turnover by synthetic Fe compounds. These results show that the direct catalytic conversion of N to the hydrazine oxidation state on molecular Fe complexes is viable and that the mechanism of NH formation by such systems may proceed via Fe-NH intermediates.