Interaction of Carbene and Olefin Donors with [Cl<sub>2</sub>PN]<sub>3</sub>: Exploration of a Reductive Pathway toward (PN)<sub>3</sub>

The iminophosphine–phosphazene [P<sup>III</sup>–P<sup>V</sup>] heterocyclic adduct [IPr·PN(PCl<sub>2</sub>N)<sub>2</sub>] was prepared via reduction of the cyclic phosphazene [Cl<sub>2</sub>PN]<sub>3</sub> in the presence of the carbene donor IPr {IPr = [(HCNDipp)<sub>2</sub>C:], where Dipp = 2,6-<sup>i</sup>Pr<sub>2</sub>C<sub>6</sub>H<sub>3</sub>}. By contrast, the treatment of [Cl<sub>2</sub>PN]<sub>3</sub> with the N-heterocyclic olefin IPrCH<sub>2</sub> yielded the olefin-grafted phosphazene ring [(IPrCH)P(Cl)N(PCl<sub>2</sub>N)<sub>2</sub>].