Hydride ion abstraction from titanocene cyclic organohydroborates, Cp2Ti{(mu-H)(2)BR2} (R-2 = C4H8, C5H10, C8H14), as a function of solvent

Hydride abstraction reactions of titanocene cyclic organohydroborate comple xes CP2Ti{(mu -H)(2)BR2} (R-2 = C4H8, C5H10, C8H14) with B(C6F5)(3) were in vestigated as a function of solvent. It was determined that the coordinatin g ability of the solvent directed the course of these abstraction reactions . The reaction in toluene, a noncoordinating solvent, produced a metathesis product, CP2Ti{(mu -H)(2)B(C6F5)(2)} (1), in which the cyclic organohydrob orate H2BR2 was substituted by H2B(C6F5)(2). In diethyl ether and THF, the salts [CP2TiL2] [HB(C6F5)(3)] (2, L = Et2O; 3, L = THF) consisting of titan ocene cations with solvent ligands were isolated. Salt 2 is the first struc turally characterized [CP2TiL2](+) cation containing diethyl ether solvent ligands. The diethyl ether molecules of the cation in 2 are weakly co ordin ated and are labilized in THF and toluene. Dissolution of 2 in THF afforded 3. The complex CP2Ti{(mu -H)B(C6F5)(3)}(OEt2) (4) and the proposed 15-elec tron species CP2Ti{(mu -H)B(C6F5)(3)} (5) were generated through the displa cement of an ether molecule from 2 by the [HB(C6F5)(3)](-) anion in toluene . Single-crystal X-ray structures of 1, 2, and 3 were determined.