Unstable intermediates

Exposure of the following phosphazenes to 60Co γ-rays at 77 K gives electron-gain centres having e.s.r. spectra characteristic of phosphoranyl radicals: N3P3X6(X = Cl or Br), N3P3Cl3(NMe2)3, and N4P4X8 (X = Cl or Br). This means that, rather than accommodating the extra electron in a delocalised π orbital of a pseudoaromatic type, the radical anion distorts so that the electron is confined to a single phosphorus atom having a local trigonal-bipyramidal configuration, with the orbital of the unpaired electron on phosphorus directed radically away from the ring. (author)