Introducing Students to Inner Sphere Electron Transfer Concepts through Electrochemistry Studies in Diferrocene Mixed-Valence Systems

Abstract

We have designed a 4 h physical chemistry laboratory to introduce upper division students to electrochemistry concepts, including mixed valency and electron transfer (ET), using cyclic and differential pulse voltammetries. In this laboratory practice, students use a ferrocene dimer consisting of two ferrocene centers covalently bonded through a dimethylethylene bridge as a platform for the measurement of inner-sphere ET. The degree of electronic communication between the ferrocene redox centers is measured by the magnitude of the equilibrium constant of the comproportionation reaction that yields the mixed-valent ferrocene dimer. Students measure the difference in E1/2 from the electrochemistry of the ferrocene dimers and categorize these ferrocene dimers according to the Robin-Day classification. We include an interactive presentation, a student handout, and one sample quiz.