Chemistry of polyfunctional molecules .123. Reactions of BiBr3, SbI3 and AsI3 with LIN(PPh(2))(2); X-ray structure of a cyclophosphazene salt containing arsenic(I)

BiBr3 or SbI3 react at 20 degrees C with LiN(PPh(2))(2) (1) to give elementary Bi or Sb and the P-P coupled phosphazene ligand Ph(2)P-N=PPh(2)-PPh(2)=N-PPh(2) (2). The reaction of AsI3 with 1 at room temperature formed yellow needles of the eight-membered heterocycle AsPPh(2)NPPh(2)AsPPh(2)NPPh(2) (3), whereas AsI3 interacted at 80 degrees C with 1 in the molar ratio of 1:3 to give elementary arsenic and 2. Treatment of AsI3 and 1 at 20 degrees C in a 1:2 stoichiometry yielded the seven-membered, cyclic arsenium (I) salt [As - PPh(2)-N=PPh(2)-PPh(2)=N-PPh(2)] I . 4THF (5 . 4THF), which was characterized by elemental analysis, conductivity, mass, IR and NMR spectroscopy and single-crystal X-ray structural analysis. Copyright (C) 1996 Elsevier Science Ltd