THE ELECTROCHEMICAL REDUCTION OF CP2TICL2 IN THE PRESENCE OF TRIMETHYLPHOSPHINE

The electrochemistry of the complexes Cp2TiClx(PMe3)2-x in anhydrous THF has been studied. The most stable complexes at the three oxidation states of titanium are Cp2TiCl2, Cp2TiCl(PMe3) and Cp2Ti(PMe3)2, and each of these species is readily formed by electrolysis. It has also been demonstrated that oxidation/reduction of these species is followed by facile and rapid ligand exchange to form the preferred species in the new oxidation state provided a stoichiometric concentration of the required ligand is present. The consequences of this redox and ligand exchange chemistry for the synthetic reactions catalyzed by lower oxidation states of Ti are discussed. Finally, the voltammetry of a titanocycle is reported, and it is shown that the corresponding Ti(III) metallocycle is stable.