Triphos–Fe dinitrogen and dinitrogen–hydride complexes: relevance to catalytic N2 reductions

The two electron reduction of iron complexes [(PRP2Cy)Fe(Cl)2] (R = Ph or tBu) 2a–b afforded complexes [(PRP2Cy)Fe(N2)2] 4a–b. Protonation of 4a at the metal center and subsequent reduction to Fe(I)–H species lead to complex [(PPhP2Cy)Fe(N2)(H)2] 6avia a spontaneous disproportionation reaction. Complex 4a behaves as one of the most efficient monometallic Fe-catalysts reported to date for N2-to-N(SiMe3)3 functionalization under atmospheric pressure.