Current Students

Ben Gerroll

Research Assistant


Chemistry A162B
800 E. Kirkwood Ave.
Bloomington, Indiana
47405 U.S.A.

Previous Education

B.S. Biology

Indiana University (2012)

Research Information

Cadmium Oxide: A Novel Electrode Coating for Metalloprotein Redox Measurement

Biological redox reactions are generally mediated by proteins that contain one or more metal cations. These metals are either coordinated directly to amino acid-residues, or incorporated as organometallic cofactors. Metalloproteins can be found across all domains of life and are involved in, but not limited to, electron-transfer reactions, the thermodynamics (redox potentials) of which are intimately linked to the metal’s coordination sphere. Cyclic voltammetry (CV) is a powerful tool for measuring redox potentials; however proteins tend to adsorb to conventional electrodes, altering protein structure and subsequently hindering further electron transfer. Thus, measurement of heterogeneous electron transfer between metalloproteins in solution and a working electrode proves difficult. Development of electrode chemical modifications paved the way for a bloom in research into the direct measurement of metalloprotein redox potentials. Cyclic voltammograms recorded at electrode surfaces modified with semiconducting materials, such as indium oxide or cadmium stannate (Cd2SnO4), have, in previous publications, displayed quasi-reversible to nearly reversible electron transfers with proteins. In the present work, cadmium oxide (CdO) prepared by electrodeposition onto tin-doped indium oxide glass slides, has been investigated as an electrode modification to provide a suitable surface for metalloprotein redox measurement. CdO electrodes have been successful in measuring redox potentials of small model systems and exhibited limited success with metalloproteins. In addition to redox measurements of metalloproteins, two organometallic catalysts were investigated as a precursor to possible future investigations into halogenated pollutant remediation via electrochemical catalysis. Catalytic reductions of cyclohexyl bromide and iodide by electrogenerated Ni(I) salen and Co(I) salen have been found to proceed through overall one electron processes to yield cyclohexane, cyclohexene, and small amounts of bicyclohexyl. Mechanistic schemes are proposed on the basis of product distributions arising from bulk electrolyses in addition to data collected voltammetrically.