Studies of the oxidation of elemental phosphorus by substituted ortho-benzoquinones

Abstract

The phosphorus compounds P(O₂C₆R)₂Br (R = Cl₄, Br₄ or Bu₂H₂) have been prepared by the reaction of P₄, Br₂ and the substituted o-benzoquinone RC₆O₂-o. There is no reaction between Bu₂H₂C₆O₂-o, P₄ and Ph₂Se₂, but in the presence of catalytic quantities of Br₂ the product is P(O₂C₆H₂Bu₂)₂(SePh). ESR spectra identify the presence of the corresponding o-semiquinone species in these reactions. The ¹³C and ³¹P NMR spectra of these phosphoranes are reported, and compared with those of P(O₂C₆R)X₃(X₃= Ph₃, Ph₂Cl, Br₃ or Cl₃) prepared by the reaction of PX₃ and RC₆O₂-o.