SYNTHESIS AND X-RAY STRUCTURE OF THE DIVALENT AND TRIVALENT YTTERBIUM-MOLYBDENUM COMPLEXES YB(II)(HMPA)4(MU-OCMO(CO)2CP)2 AND HMPA)5(MU-OCMO(CO)2CP)][CPMO(CO)3]2-CENTER-DOT-THF

Reaction of the ytterbium-benzophenone dianion complex [YbII(mu-OCPh2) (HMPA)2]2 with two molar equivalents of CpMo(CO)3H in THF/ HMPA (THF = tetrahydrofuran, HMPA = hexamethylphosphoramide) gave a divalent ytte rbium-molybdenum complex YbII(HMPA)4(mu-OCMo(CO)2CP)2 (1) in which the two molybdenumcarbonylate units are coordinated to Yb(II) in cisoid o rientation. When four equivalents Of CPMO(CO)3H were used, the trivale nt ytterbium-molybdenum complex [YbIII(HMPA)5(mu-OCMo(CO)2CP)][CPMo(CO )3]2. THF (2) was formed. Both 1 and 2 were structurally characterized by X-ray crystallography.