Exploring the Stability of Primary Phosphine Oxides: Correlation with Primary Phosphine′s Air-Stability?

To better understand the stability of isolable primary phosphine oxides, new members of this family were synthesized through the oxidation of the corresponding phosphines. Specifically, the previously reported air-stable primary phosphines (R)-2-phosphanyl-2’-methoxy-1,1’-binaphthyl, 9,10-dihydro-9,10-etheno-anthracen-9-yl phosphine, and 3-phosphino-2-naphthol were treated with hydrogen peroxide or meta-chloroperoxybenzoic acid to yield the new primary phosphine oxides. The compounds were characterized using NMR, MS, EA, and X-ray crystallography. The oxides were further investigated in thermal disproportionation, and studied as ligands in half-sandwich Ru(II) complexes bearing an auxiliary η⁶-p-cymene ligand.