SYNTHESIS AND STRUCTURE OF ORGANOSILICON AND ORGANOGERMANIUM COMPLEXES OF YTTERBIUM (PH3E)2YB(THF)4 WITH YB-SI AND YB-GE BONDS

Complexes (Ph3Si)2Yb(THF)4 (1) and (Ph3Ge)2Yb(THF)4 (2) were synthesised by the reactions of Ph3SiCl or Ph3GeCl with ytterbium in THF and characterised by X-ray diffraction. Compounds 1 and 2 have similar centrosymmetrical octahedral structures with a central Yb atom bonded to four oxygen atoms of THF molecules in equatorial positions and two Si (or Ge) atoms of SiPh3 (or GePh3) fragments in axial positions. In the crystal of 2 there are two symmetrically independent molecules with the same structure. The Yb-Si and Yb-Ge distances in 1 and 2 are 3.158(2) and 3.170(2), 3.141(2) angstrom, respectively.