Synthesis and characterization of paramagnetic triazenido complexes of rhenium(III). The crystal structure ofdichloro[1,3-bis(p-tolyl)triazenido-N1,N3]bis(triphenylphosphine)ruthenium(III)

ReOCl3(PPh3)2 reacts with Li[RN3R] (R = p-XC6H4, X = Me, H, F, Cl) in boiling THF to give ReCl2[N(NR)2](PPh3)2. IR spectra suggest that the triazenido ligand is chelating and that the 2Cl ligands are in cis positions. Magnetic susceptibility measurements on the solids show the presence of unpaired electrons, which affect the 1H NMR spectra, the resonance signals being shifted up- and downfield with respect to SiMe4. The crystal and mol. structure of the title complex was detd. by x-ray diffraction using std. heavy-atom methods, and refined by full-matrix least squares to R 0.075 for 2702 independent reflections. The Rh atom is in a distorted octahedral coordination with 2 axial PPh3 groups, 2 cis Cl atoms, and the chelate ligand which forms a 4-membered ring with the metal.