INVESTIGATION OF THE ELECTROCHEMICAL PROPERTIES OF SUBSTITUTED TITANOCENE DICHLORIDES

The electrochemical properties of(eta(5)-C(5)Me(5))(2)TiCl2, (eta(5)-C(5)H(4)Me)(2)TiCl2, (eta(5)-C5H4Cl)(2)TiCl2, (eta(5)-C(5)H(4)CO(2)Me)(2)TiCl2, and (eta(5)-C5H5)(2)TiCl2 were examined in THF. All five species undergo two reduction processes. The first reduction processes of (eta(5)-C(5)H(4)Me)(2)TiCl2, (eta(5)-C5H4Cl)(2)TiCl2 and (eta(5)-C5H5)(2)TiCl2 are characterized as one-electron reversible reductions. The other two compounds have one-electron reduction followed by the loss of a chloride in a slow chemical reaction tie EC mechanism). Steric bulk of the pentamethyl derivative and the possibility of chelation in the carbomethoxy derivative enhance the loss of a chloride ion. An E(1/2) range of 550 mV was obtained for the five titanocenes and E(1/2)decreased to more negative values in the order: C(5)H(4)CO(2)Me > C5H4Cl > C5H5 > C(5)H(4)Me > C(5)Me(5).