trans-Bis(triphenylphosphin)phthalocyaninato(2-)rhenium(II): Synthese, Eigenschaften und Kristallstruktur

Dirheniumheptoxide reacts with phthalodinitrile in boiling 1-chloronaphthalene and subsequent reprecipitation of the green raw product from cone. sulfuric acid to yield an oxo-phthalocyaninate of rhenium, which is reduced by molten triphenylphosphine forming dark green trans-bis (triphenylphosphine)phthalocyaninato(2-)rhenium(II), (trans)[Re(PPh3)(2)pc(2-)]. The latter crystallizes triclinic in the space group P (1) over bar with the cell parameters as follows: a = 11.512(2) Angstrom, b = 12.795(2) Angstrom, c = 12.858(2) Angstrom, alpha = 64.42(2)degrees, beta = 79.45(2)degrees, gamma = 72.74(1)degrees; V = 1628.1(5); Z = 1. Re is in the centre of the (N-p)(4) plane (N-p: N1, N3) and coordinates two triphenylphosphine ligands axially in trans position. The average Re-N-p and Re-P distances are 2.007(1) and 2.516(3) Angstrom, respectively. Despite the many extra bands the typical B, Q and N regions of the pc(2-) ligand are observed at ca. 16500, 28900/32900 and 35300 cm(-1). A weak band group at ca. 8900 cm(-1) is attributed to a trip-multiplet transition, another one at ca. 14500 cm(-1) to a P --> Re charge transfer. The vibrational spectra are dominated by internal vibrations of the pc(2-) ligand. The very weak intensity of the IR bands at 905 and 1327 cm(-1) are diagnostic of the presence of Re-II.