Valence-shell photoionization spectra of some methyl dihalogenophosphates

Abstract

He(I) photoelectron spectra of PX₂O(OMe)(X = F, Cl, or Br), PCl₂O(OEt), and PCl₂(OMe)S are reported, and the peaks are assigned on the grounds of systematic comparisons throughout the investigated series, with the parent POX₃(PSX₃) compounds, and with results from CNDO/2 calculations. Twelve out of the 19 (for the methyl compounds) valence orbitals can thus be identified, with characterizing contributions from specific bond orbitals or groups of bond orbitals, including (in approximate order of decreasing orbital energy)π_PO or π_PS > π_X∼π_OMe∼σ_CH(higher levels)∼σ_POOζσ_PS > σ_PX > σ_CH(lower levels)∼σ_OC. Evidence is given for the inductive effect of halogens, and for some splitting and mixing effects related to the low symmetry of the investi-gated molecules.