Unleashing Phosphorus Mononitride: Formation of PN-Multiple Bonded Exemplars [NPS2]2–, [NPCl]–, and [PN4]–

The interstellar diatomic molecule, phosphorus mononitride (P≡N), is highly unstable under conditions typical on Earth, and its utility for constructing elusive P–N multiply-bonded archetypes is essentially uncharted. Herein, we show how Na(OCP) transfers a P atom to an electrophilic osmium nitride complex to form a terminally bound P≡N functionality. Quantum chemical calculations and X-ray absorption spectroscopy unveil a cumulenic [Os(IV)=N=P] electronic structure comprising orthogonal Os=N and N=P π-bonding. The highly reduced P≡N ligand, formally [PN]2–, undergoes two-fold oxidation with elemental sulfur to form a trigonal planar [NPS2]2– group. On reaction with Ph3CCl, the P≡N ligand forms a bent [NPCl]– motif coordinated to Os(III) (S = ½). [3+2] cycloaddition of this radical species with Me3SiN3 forms an aromatic heterocyclic interpnictide, [PN4]–, that is inaccessible from the parent P≡N system.