Effect Of Solvent In The Reaction Of Cp2zrh{(Mu-H)(2)Br2} (R-2 = C4h8, C8h14)With B(C6f5)(3): Formation Of [Hb(C6f5)(3)](-) Salts Of The Unsupported Hydrogen-Bridged Cations [(Mu-H){Cp2zr(Mu-H)(2)Br2}(2)]+ (R-2 = C4h8, C8h14) And [Cp2zr(Oet2)X](+) (X = Oet, {(Mu-H)(2)Bc8h14})

Hydride abstraction reactions of the zirconocene cyclic organohydroborate complexes Cp2ZrHf(mu-H)(2)BR2} (R-2 = C4H8, 1; C8H14, 2) with B(C6F5)(3) were observed as a function of solvent. The reaction in poorly coordinating solvents, benzene and toluene, forms [HB(C6F5)(3)](-) salts of Zr-H-Zr hydrogen-bridged cations [(mu-H){Cp2Zr(mu-H)(2)BR2}(2)](+) (R-2 = C4H8, 3; C8H14, 4), in which there is no direct metal-metal bonding between the bridged metals. The unsupported hydrogen-bridged bond in complex 4 was cleaved when it was dissolved in the coordinating solvent THF to produce the neutral complex 2 and the ionic complex [Cp2Zr(THF){(mu-H)(2)BC8H14][HB(C6F5)(3)]. In the coordinating solvent, diethyl ether, the salts of [Cp2Zr(OEt2)X](+)[HB(C6F5)(3)](-) (X = OEt, 5; {(mu-H)(2)BC8H14}, 6) consisting of zirconocene cations with coordinated solvent ligands were isolated. The formation of 5 involves hydride insertion from zirconium into the carbon oxygen bond of one the coordinated ethers, resulting in the liberation of ethane and the formation of an ethoxyl group coordinated to zirconium. The diethyl ether molecules in the cations 5 and 6 are weakly coordinated to Zr and are displaced in THF solution. Single-crystal X-ray structures of 3, 4, and 5 were determined.