COORDINATION OF CB11H12-TO CATIONIC ZIRCONIUM(IV) COMPLEXES - SYNTHESIS AND STRUCTURES OF (C5H5)2ZR(ETA-2-CH2PH)(CB11H12), (C5H4ME)2ZR(CH3)(CB11H12), AND (C5ME5)ZR(CH3)2(CB11H12)

The reaction of Ag[CB11H12] with CP2Zr(CH2Ph)2 yields CP2Zr(eta2-CH2Ph)(eta1-CB11H12) (1), in which the carborane coordinates to Zr via a single B-H-Zr bridge involving the B-H bond trans to the carbon of the closo CB11H12- anion. Data for 1: a = 9.802(5) angstrom, b = 13.663(5) angstrom, c = 10.860(4) angstrom, beta = 92.48(4)-degrees, V = 1453(2) angstrom3, Z = 2, in space group P2(1)/m. A similar structure is observed for CP'2Zr(CH3)(eta1-CB11H12) (2, Cp' = C5H4Me), which is prepared by reaction of CP'2Zr(CH3(2 with Ag[CB11H12]. Data for 2: a = 13.504(2) angstrom, b = 19.432(3) angstrom, c = 7.919(1) angstrom, V = 2078(1) angstrom3, Z = 4, in space group Pnn2. The reaction of Cp*Zr(CH3)3 (Cp* = C5Me5) with Ag[CB11H12] yields Cp*Zr(CH3)2(eta3-CB11H12) (3), in which the carborane coordinates in a unique tridentate fashion via three B-H-Zr bridges involving the B-H bonds on a triangular face opposite the carborane carbon. Data for 3: a = 12.360(3) angstrom, b = 19.450(4) angstrom, c = 9.161(2) angstrom, beta = 90.93(4)-degrees, V = 2202(1) angstrom3, Z = 4, in space group P2(1)/c. Complex 1 polymerizes ethylene, and 2 oligomerizes propene under mild conditions, while 3 is unreactive with propene, 2-butyne, or styrene, apparently due to the lower lability of the tridentate carborane ligand. The CB11H12- ligands of 1-3 are rapidly displaced by CH3CN or THF.