SYNTHESIS AND STRUCTURE OF DONOR-LIGAND-STABILIZED TRIS(CYCLOPENTADIENYL)ZIRCONIUM CATIONS

Treatment of Cp(2)Zr(Cl)CH3 (6) with;sodium cyclopentadienide gives Cp (3)ZrCH(3) (7). Its reaction with dimethylanilinium tetraphenylborate yields the Cp(3)Zr(THF)(+) cation. [CP3Zr+CH3B(C6F5)(3)(-)] (9) is gen erated by treatment of 7 with tris(pentafluorophenyl)borate. Nitriles add to 9 to form the ligand-stabilized tris(eta 5-cyclopentadienyl)zir conium cation systems Cp(3)Zr(N=CR)(+). With tert-butyl isocyanide, 9 is transformed to yield the donor-ligand-stabilized [Cp(3)Zr(C=NCMe)(3 )(CH3B)-C-+(C3F5)(3)(-)] salt 12. Carbon monoxide adds to 9 to give th e cationic metal carbonyl complex [Cp(3)Zr(CO)(CH3B)-C-+(C6F5)(3)(-)] (13). Both cation complexes 12 and 13 were characterized by X-ray diff raction.