The fundamental nature of Ti-III complexes generated in tetrahydrofuran by reduction Of Cp2TiCl2 has been clarified by means of cyclic voltammetry and kinetic measurements. While the electrochemical reduction Of Cp2TiCl2 leads to the formation of Cp2TiCl2-, the use of metals such as Zn, Al, or Mn as reductants affords Cp2TiCl and (Cp2TiCl)(2) in a mixture having a dimerization equilibrium constant of 3 x 10(3) M-1, independent of the metal used. Thus, we find it unlikely that the trinuclear complexes or ionic clusters known from the solid phase should be present in solution as previously suggested. The standard potentials determined for the redox couples Cp2TiCl2/Cp2TiCl2-, (Cp2TiCl)(2)(+)/(Cp2TiCl)(2), Cp2TiCl+/Cp2TiCl, and Cp2Ti2+/Cp2Ti+ increase in the order listed. However, the reactivity of the different Ti-III complexes is assessed as (Cp2TiCl)(2) greater than or similar to Cp2TiCl2 approximate to Cp2Ti+ much greater than Cp2TiCl2- in their reactions with benzyl chloride and benzaldehyde. None of the reactions proceed by an outer-sphere electron transfer pathway, and clearly the inner-sphere character is much higher in the case Of Cp2Ti+ than for (Cp2TiCl)(2), Cp2TiCl, and in particular Cp2TiCl2-. As to the electron acceptor, the inner-sphere character increases, going from benzyl chloride to benzaldehyde, and it is suggested that the chlorine atom in benzyl chloride and the oxygen atom in benzaldehyde may function as bridges between the reactants in the transition state.