Dinitrogen reduction by a chromium(0) complex supported by a 16-membered phosphorus macrocycle.

We report a rare example of a Cr-N2 complex supported by a 16-membered phosphorus macrocycle containing pendant amine bases. Reactivity with acid afforded hydrazinium and ammonium, representing the first example of N2 reduction by a Cr-N2 complex. Computational analysis examined the thermodynamically favored protonation steps of N2 reduction with Cr leading to the formation of hydrazine.