Intermediates in Nitrogenase Models: N2H3 and N2H4 as η2‐Coordinated Ligands

The complex cations 1 and 2 have model character for the active centers of nitrogenases even though neither phosphane ligand nor cobalt occur in the known nitrogenases. Nevertheless, these cations show how a quite specific ligand environment can facilitate the fixation to metal centers of the N2H3 and N2H4 intermediates said to be formed on N2 reduction.