Phosphoraneiminato complexes of rare earth elements. Syntheses and crystal structure of [M2(C5H5)3(NPPh3)3]. 3 C7H8 mit M = Y, Dy, and Er. Magnetic properties of [Dy2(C5H5)3(NPPh3)3] . 3 C7H8

The title compounds have been prepared by reactions of the cyclopentadienidchlorides [M(C5H5)2Cl]2 with LiNPPh3 in boiling toluene, and they were characterized by crystal structure determinations. All three compounds crystallize isotypicly with one another within the orthorhombic space group Pbca with Z = 8. Two of the three phosphoraneiminato groups link the metal atoms via μ2-N atoms to almost planar M2N2 four-membered rings. The third NPPh3-group is terminally bonded. The magnetic susceptibility of [Dy2(C5H5)3(NPPh3)3] . 3 C7H8 has been determined (SQUID magnetometer) in the temperature range 1.7 K-300 K at magnetic fields between 0.01 T and 5 T. Calculations based on a cubic ligand field model lead to a satisfactory simulation with reasonable ligand field parameters. The inclusion of isotropic intramolecular exchange interactions in the model does not improve the fit, so that in the framework of the applied model no hints to a spin-spin coupling within the dinuclear units are obtained. (orig.)