The Metaphosphite (PO₂⁻) Anion as a Ligand

Abstract

The utilization of monomeric, lower phosphorous oxides and oxoanions, such as metaphosphite (PO2−), which is the heavier homologue of the common nitrite anion but previously only observed in the gas phase and by matrix isolation, requires new synthetic strategies. Herein, a series of rhenium(I–III) complexes with PO2− as ligand is reported. Synthetic access was enabled by selective oxygenation of a terminal phosphide complex. Spectroscopic and computational examination revealed slightly stronger σ‐donor and comparable π‐acceptor properties of PO2− compared to homologous NO2−, which is one of the archetypal ligands in coordination chemistry.