SYNTHESIS AND CHARACTERIZATION OF PENTAPHENYLDIYTTERBIUM PH2YB(THF)(MU-PH)3YB(THF)3

The binuclear ytterbium complex Ph2Yb(THF)(mu-Ph)3Yb(THF)3 (1) was obtained in reactions of naphthaleneytterbium C10H8Yb(THF)2 with diphenylmercury or triphenylbismuth in THF. An X-rav crystallographic study (a = 11.099(2), b = 19.876(4), c = 19.723(4) angstrom, beta = 103.33(3)-degrees, Z = 2, space group P2(1)) showed that the molecule of 1 has two Yb atoms coupled by three bridging Ph groups, which are linked with the first Yb atom by an eta-1 bond and with the second one by an unsymmetrical n-2 bond. In addition the first Yb atom has an eta-1 bond with two terminal Ph groups and one coordinated THF molecule whereas the second Yb atom is linked with three THF molecules. The coordination of both Yb atoms is a distorted octahedron. In the crystal, there are two symmetrically independent molecules of 1 with a similar structure. The Yb-C (terminal Ph) bond length is 2.388-2.463 angstrom. The eta-1- and eta-2-Yb-C (bridging Ph) bond distance varies in the ranges 2.475-2.584, 2.547-2.751 and 2.877-3.250 angstrom. The magnetic moment mu(eff) (per Yb(III) atom) is 4.0 +/- 0.05-mu(B). Reactions of 1 with water, HCl, Br2, MeI and CO2 give benzene, bromobenzene, toluene and PhCOOH, respectively.