SYNTHESIS OF BIS(CYCLOPENTADIENYL)DIAZADIENE COMPLEXES OF YTTERBIUM -AN X-RAY STRUCTURAL STUDY OF THE )YB(MU-ETA(2)-ETA(2)-BU(T)-N=CH-CH=N-BU(T))LI(DME) COMPLEX

Ytterbium complexes, Cp(2)Yb(mu-eta(2):eta(2)-DAB)Li(DME) (1) and CpYb (DAB)K(THF)(2) (2), containing a bridging diazadiene ligand were prepa red by the reaction of CpYbCl(2)(THF)(3) with (DAB)Li-2 (1:1) and (DAB )K--(+) (1:2) (DAB = Bu(t)-N=CH-CH=N-Bu(t)). The structure of complex 1 was established by X-ray diffraction analysis. The complex is binucl ear: the Yb atom of the Cp(2)Yb fragment and the Li atom, which is bon ded as well with the chelating DME molecule, are linked by the DAB lig and.