The iron oxo unit, [Fe=O] n + is a critical intermediate in biological oxidation reactions. While its higher oxidation states are well studied, relatively little is known about the least-oxidized form [Fe III =O] + . Here, the thermally stable complex PhB(AdIm) 3 Fe=O has been structurally, spectroscopically, and computationally characterized as a bona fide iron(III) oxo. An unusually short Fe–O bond length is consistent with iron–oxygen multiple bond character and is supported by electronic structure calculations. The complex is thermally stable yet is able to perform hydrocarbon oxidations, facilitating both C–O bond formation and dehydrogenation reactions.

The N 2 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≡N t Bu releases the mononuclear complex [(N 3 N)Mo—PN] − , N 3 N = [(Me 3 SiNCH 2 CH 2 ) 3 N] 3– ), which undergoes light-induced linkage isomerization to provide [(N 3 N)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.

The syntheses of (DIM)Ni(NO3)2 and (DIM)Ni(NO2)2, where DIM is a 1,4-diazadiene bidentate donor, are reported to enable testing of bis boryl reduced N-heterocycles for their ability to carry out stepwise...