[YB3OBR4(N(SIME3)(2))(3)(THF)(3)], AN AMI DO COMPLEX OF YTTERBIUM WITH A CLUSTER-LIKE STRUCTURE

The title compound has been prepared from YbBr3 and NaN(SiMe3)(2) in T HF suspension, forming yellow single crystals from hexane solutions wh ich were characterized by a crystal structure determination. Space gro up <P(1)over bar>, Z=2, lattice dimensions at -100 degrees C: a=1085.4 (1), b=1410.2(1), c=1912.0(1) pm; alpha=78.62(1)degrees, beta=80.61(1) degrees, gamma= 73.45(1)degrees, R=0.025. In the molecular structure o f [Yb3OBr4{N(SiMe3)(2)}(3)(THF)(3)] the three ytterbium atoms together with the mu(3)-oxygen atom and a mu(3)-bromine atom form a distorted trigonal bipyramid. In addition, three mu(2)-Br atoms coordinate the Y b atoms in the equatorial plane, whereas the THF molecules and the N(S iMe3)(2)(-) ligands are terminally coordinated, thus forming a distort ed octahedrally surrounding of the Yb atoms.