PHOSPHORANYL RADICALS - ESR STUDY OF PH3PBR TRAPPED IN A SINGLE-CRYSTAL

X-irradiation of a single crystal of triphenyliminophosphonim bromide yields an oriented free radical which is identified via its ESR spectrum as the triphenylbromophosphoranyl radical, Ph3PBr. The g tensor, the magnetic hyperfine tensors of the 31P and 81Br nuclei and the quadrupole coupling tensor of the 81Br nucleus are reported. the directions of the maximum value of the 31P magnetic hyperfine tensor and of the 81Br magnetic hyperfine tensor are inclined at an angle of 35° thus indicating a structure intermediate between the C2v structure of PF4 and the C3v structure of Ph3PCI. © 1979.