Stabilization of the Dinitrogen Analogue, Phosphorus Nitride

The N2 analogue phosphorus nitride (PN) was the first phosphorus-containing compound to be detected in the interstellar medium; however, this thermodynamically unstable compound has a fleeting existence on Earth. Here, we show that reductive coupling of iron­(IV) nitride and molybdenum­(VI) phosphide complexes assembles PN as a bridging ligand in a structurally characterized bimetallic complex. Reaction with CNtBu releases the mononuclear complex [(N3N)­MoPN]−, N3N = [(Me3SiNCH2CH2)3N]3–), which undergoes light-induced linkage isomerization to provide [(N3N)­MoNP]−, as revealed by photocrystallography. While structural and spectroscopic characterization, supported by electronic structure calculations, reveals the PN multiple bond character, coordination to molybdenum induces a nucleophilic character at the terminal atom of the PN/NP ligands. Indeed, the linkage isomers can be trapped in solution by reaction with a Rh­(I) electrophile.