Cationic cyclopentadienyl phenylenediamido titanium species generated by reaction of TiCpR[1,2-C6H4(NCH2t-Bu)2]R (CpR = η5-C5H5, η5-C5Me5; R = CH3, CH2Ph) with B(C6F5)3. -: X-ray -: Molecular structure of Ti(η5-C5Me5)[1,2-C6H4(NCH2t-Bu)2][μ-MeB(C6F5)3]

The reaction of TiCpR[1,2-C6H4(NNP)(2)]R with the Lewis acid B(C6F5)(3) in noncoordinating solvent affords the new zwitterionic species TiCpR[1,2-C6H4(NNP)(2))][mu-RB(C6F5)(3)]. When the reaction is performed in dichloromethane, the [mu-RB(C6F5)(3)](-) anion is displaced by solvent molecules, giving ionic products in which the anion is not coordinated. The cyclopentadienyl zwitterionic complexes TiCp[1,2-C6H4(NNP)(2)][mu-RB(C6F5)(3)] decompose via ligand scrambling between boron and titanium to give the neutral titanium complex TiCp[1,2-C6H4(NNp)(2)](C6F5) along with the byproduct RB(C6F5)(2). In contrast, the pentamethylcyclopentadienyl analogues TiCp*[1,2-C6H4(NNP)(2)][mu-RB(C6F5)(3)] evolve through C-H activation to yield an unresolved mixture of compounds. The molecular structure of TiCp*[1,2-C6H4(NNP)(2)][mu-MeB(C6F5)(3)] has been determined by X-ray diffraction methods.