REACTIVITY OF 17-ELECTRON AND 19-ELECTRON ORGANOMETALLIC COMPLEXES - FORMATION OF BENT SANDWICH 19-ELECTRON RADICAL-CATION COMPLEXES OF OSMIUM AND RUTHENIUM

Redox behavior of indenyl sandwich complexes of general formula (eta(5 )-C9H7)ML (M = Ru and L = eta(5)-C9H7 (I), eta(5)-C5H5 (II), eta(5)-C( 5)Me(5) (III); M = Os, L = eta(5)-C9H7 (IV)) has been studied by means of cyclic voltammetry at the Pt-electrode at -85-20 degrees C in THF, MeCN and CH2Cl2. The title complexes have been found to undergo rever sible one-electron oxidation to corresponding radical cations, whose s tability and reactivity depend on the nature of both a metal and the s econd aromatic pi-ligand L and nucleophilic properties of the solvent. Fast reversible interaction of the electrogenerated 17-electron radic al cations with nucleophiles yields bent sandwich 19-electron radical cations, [(eta(5)-C9H7)M(Nu)L](+.)(Nu = Cl-, MeCN, THF), the latter un dergo one-electron oxidation to corresponding 18-electron [(eta(5)-C9H 7)M(Nu)L](2+) dications.