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)(N-2) (2), which was crystallographically characterized. We report that under N-2 atmosphere the only observable nitrogen complex in solution is actually the terminal dinitrogen complex (PCP) Ir(N-2). The mono- and dinuclear species are in equilibrium; the dinuclear complex more readily crystallizes from solution.