Electrochemistry of bis(indenyl)dimethylzirconium complex - the precursor of the olefin polymerization catalyst

The reduction in. THF and oxidation in CH2Cl2 of the bent-sandwich complex (eta(5)-Ind)(2)ZrMe2 (1) (Ind = C9H7, indenyl) were studied by cyclic volta mmetry. Complex 1 in THF undergoes one-electron reduction to radical anion 1(.-), which partially decomposes with the liberation of the Ind(-) anion. Even at -45 degrees C the one-electron oxidation leads to the formation of an unstable 15-electron radical cation undergoing fast heterolytic decompos ition to the Me-. radical and (eta(5)-Ind)(2)ZrMe+ cation, which is the key reaction center in the catalytic polymerization of olefins. Comparative an alysis of electron-transfer-induced transformations of bent-sandwich dimeth yl and dichloride zirconocenes of the general formula L2ZrX2 (L = eta(5)-In d, eta(5)-Cp; X = Cl, Me) was performed.