Ferrocene

Electrochemical experiments were carried out in a nitrogen-filled glove box. Tetra(n-butylammonium) hexafluorophosphate (0.10 M; Sigma-Aldrich; electrochemical grade) in acetonitrile served as the supporting electrolyte. Measurements were made with a Gamry Reference 600 Plus Potentiostat/ Galvanostat using a standard three-electrode configuration. The working electrode was the basal plane of highly oriented pyrolytic graphite (HOPG, GraphiteStore.com, Buffalo Grove, Ill.; surface area: 0.09 cm²), the counter electrode was a platinum wire (Kurt J. Lesker, Jefferson Hills, PA; 99.99%, 0.5 mm diameter), and a silver wire immersed in electrolyte served as a pseudo-reference electrode (CH Instruments). The reference was separated from the working solution by a Vycor frit (Bioanalytical Systems, Inc.). Ferrocene (Sigma Aldrich; twice-sublimed) was added to the electrolyte solution at the conclusion of each experiment (~1 mM); the midpoint potential of the ferrocenium/Ferrocene couple (denoted as Fc^+/0) served as an external standard for comparison of the recorded potentials. Concentrations of analyte for cyclic voltammetry were typically 2 mM.

Electrochemical experiments were carried out in a nitrogen-filled glove box (in the dark for Mn-containing samples). 0.10 M tetra(n-butylammonium) hexafluorophosphate (Sigma-Aldrich; electrochemical grade) in acetonitrile served as the supporting electrolyte. Measurements were made with a Gamry Reference 600 Plus Potentiostat/ Galvanostat using a standard three-electrode configuration. The working electrode was the basal plane of highly oriented pyrolytic graphite (HOPG, GraphiteStore.com, Buffalo Grove, Ill.; surface area: 0.09 cm²), the counter electrode was a platinum wire (Kurt J. Lesker, Jefferson Hills, PA; 99.99%, 0.5 mm diameter), and a silver wire immersed in electrolyte served as a pseudo-reference electrode (CH Instruments). The reference was separated from the working solution by a Vycor frit (Bioanalytical Systems, Inc.). Ferrocene (Sigma Aldrich; twice-sublimed) was added to the electrolyte solution at the conclusion of each experiment (~1 mM); the midpoint potential of the ferrocenium/Ferrocene couple (denoted as Fc^+/0) served as an external standard for comparison of the recorded potentials. Concentrations of analyte for cyclic voltammetry were typically 1 mM.

Electrochemical experiments were carried out in a nitrogen-filled glove box. 0.10 M tetra(n-butylammonium)hexafluorophosphate (Sigma-Aldrich; electrochemical grade) in THF served as the supporting electrolyte. Measurements were made with a Gamry Reference 600 Plus Potentiostat/Galvanostat using a standard three-electrode configuration. The working electrode was the basal plane of highly oriented pyrolytic graphite (HOPG) (GraphiteStore.com, Buffalo Grove, Ill.; surface area: 0.09 cm²), the counter electrode was a platinum wire (Kurt J. Lesker, Jefferson Hills, PA; 99.99%, 0.5 mm diameter), and a silver wire immersed in electrolyte served as a pseudo-reference electrode (CH Instruments). The reference was separated from the working solution by a Vycor frit (Bioanalytical Systems, Inc.). Ferrocene (Sigma Aldrich; twice-sublimed) was added to the electrolyte solution at the conclusion of each experiment (~1 mM); the midpoint potential of the ferrocenium/Ferrocene couple (denoted as Fc^+/0) served as an external standard for comparison of the recorded potentials. Concentrations of analyte for cyclic voltammetry were typically 2 mM.