Triphos-Fe dinitrogen and dinitrogen-hydride complexes: relevance to catalytic N-2 reductions

The two electron reduction of iron complexes [((PP2Cy)-P-R)Fe(Cl)(2)] (R = Ph or tBu) 2a-b afforded complexes [((PP2Cy)-P-R)Fe(N-2)(2)] 4a-b. Protonation of 4a at the metal center and subsequent reduction to Fe(i)-H species lead to complex [((PP2Cy)-P-Ph)Fe(N-2)(H)(2)] 6avia a spontaneous disproportionation reaction. Complex 4a behaves as one of the most efficient monometallic Fe-catalysts reported to date for N-2-to-N(SiMe3)(3) functionalization under atmospheric pressure.