Dinitrogen Complexes of Pincer-Ligated Iridium

Precursors of the fragment (PCP)Ir have been previously reported to react with dinitrogen to give the bridging dinuclear complex [(PCP)Ir]₂(N₂) (2), which was crystallographically characterized. We report that under N₂ atmosphere the only observable nitrogen complex in solution is actually the terminal dinitrogen complex (PCP)Ir(N₂). The mono- and dinuclear species are in equilibrium; the dinuclear complex more readily crystallizes from solution.