Voltammetric Studies on Decaphenylferrocene, Substituted Decaphenylferrocenes, and Their Oxidized Forms in Dichloromethane and Ionic Liquids

Cyclic voltammetric studies have been undertaken on highly insoluble decaphenylferrocene (DPFc), on substituted forms of the compound [methyl (Me(2)DPFc, Me(6)DPFc, and Me(10)DPFc), bromide (Br(2)DPFc), and ethynyl (Ethin(2)DPFc)], and on their more soluble one-electron-oxidized DPFc(+) forms. Studies with DPFc(+) and its derivatives dissolved in dichloromethane (DCM) enable the reversible potentials (E-0') of one-electron reduction processes, DPFc(+)(DCM) + e(-) reversible arrow DPFc(DCM), to be established. E-0' values obtained from these measurements exhibit the expected substituent dependence. Voltammetric studies with arrays of insoluble DPFc microparticles adhered to an electrode surface in contact with DCM (0.1 M Bu4NPF6) or ionic liquids are connected to the oxidized solid or dissolved forms of DPFc(+) via a range of pathways that are determined by the kinetics and thermodynamics of dissolution and reprecipitation processes. Comparative data obtained with more soluble ferrocene, ferricinium, and decamethylferrocene microparticles support the hypothesis that dissolution processes play an important role in determining the nature of the voltammetric response of adhered microparticles.