Selective Catalytic Reduction of N2 to N2H4 by a Simple Fe Complex

The catalytic fixation of N-2 by molecular Fe compounds is a rapidly developing field, yet thus far few complexes can effect this transformation, and none are selective for N2H4 production. Herein we report that the simple Fe(0) complex Fe(Et2PCH2CH2PEt2)(2)(N-2) (1) is an efficient catalyst for the selective conversion of N-2 (>25 molecules N-2 fixed) into N2H4, attendant with the production of ca. one molecule of NH3. Notably, the reductant (CoCp*(2)) and acid (Ph2NH2OTf) used are considerably weaker than conventional chemical H+ and e(-) sources used in previous demonstrations of N-2 turnover by synthetic Fe compounds. These results show that the direct catalytic conversion of N-2 to the hydrazine oxidation state on molecular Fe complexes is viable and that the mechanism of NH3 formation by such systems may proceed via Fe N2H4 intermediates.