Spectroscopically pure bis(phthalocyaninato)protactinium (IV)

Spectroscopically pure PaPc2 has been prepared by reaction between PaI4 x 4 CH3CN and o-phthalic acid dinitrile in 1-chloronaphthalene followed by sublimation at 5 x 10-3 Pa in a temperature profile with three clearly defined zones (5200C/3500C/room temperature). This procedure gives a product almost completely free of H2Pc impurity which is known to have been present in previously reported complexes of the type AnPc2. Thus, the trace of H2Pc in the substance could only be detected by derivative spectroscopy. X-ray powder diffraction shows the compound to be isostructural with ThPc2 and UPc2. The ligand spectrum is typical of AnPc2 complexes. f-f bands observed in a solid state spectrum provide additional proof that the compound is Pasup(I)sup(V)Pc2. (orig.)