Photoinduced oxidation of triphenylphosphine isolated in a low-temperature oxygen matrix

Photooxidation reactions of triphenylphosphine (Ph3P) monomers isolated in matrices of solid oxygen at 10 K were characterized by means of infrared spectroscopy. Upon UV (λ > 280 nm) irradiation of O2 matrices, ca. 90% of Ph3P was converted to triphenylphosphine oxide (Ph3PO), with concomitant formation of ozone. In the competing photoreaction, ca. 10% of Ph3P was converted to diphenyl-phenyl-phosphinate, Ph2(Ph−O−)PO. The interpretation was assisted by theoretical [DFT(B3LYP)/6-31G(d, p)] calculations of vibrational spectra, as well as by comparison with the experimental vibrational data from separate experiments in which monomeric Ph3P and Ph3PO were isolated in argon and oxygen matrices at 10 K.