Phosphaethene. Synthesis by Vacuum Gas-Solid Reaction (VGSR) and Characterization by Photoelectron Spectroscopy

Article abstract of DOI:10.1021/ja00229a005

Phosphaethene, the unstable parent compound in the phosphaalkenes series, has been thoroughly investigated using theoretical calculations.For the first time, its electronic structure is evidenced from its photoelectron spectrum.The PE spectra of phosphaethene and 1-phosphapropene, generated in the gas phase by the respective vacuum dehydrochlorination of chloromethylphosphine and 1-chloroethylphosphine, have been recorded in situ by the use of a vacuum device directly coupled to the spectrophotometer.The vertical ?_P=C and n_p ionization energies are observed respectively at 10.30 and 10.70 eV for phosphaethene and 9.75 and 10.35 eV for 1-phosphapropene.The band's characterizations are discussed through correlations with the corresponding imines and with substituted phosphaalkenes and are confirmed by ab initio theoretical calculations.The results indicate a rather significant energetic separation between the two first ?_P=C and n_p ionic states.