US EPA

2880819 

Journal Article 

Metallocenes as references for the determination of redox potentials by cyclic voltammetry - Permethylated iron and cobalt sandwich complexes, inhibition by polyamine dendrimers, and the role of hydroxy-containing ferrocenes 

Aranzaes, JR; Daniel, MC; Astruc, D 

2006 

Yes 

Canadian Journal of Chemistry
ISSN: 0008-4042
EISSN: 1480-3291 

84 

2 

288-299 

10.1139/V05-262 

WOS:000237417600027 

Measurement of the redox potentials (E-1/2) of ferrocene (1), decamethylferrocene (2), decamethylcobaltocene (3), and [(FeCp)-Cp-I*(eta(6)-C6Me6)] (4) (Cp* = eta(5)-C5Me5) in DMF, CH3CN, THF, DME, CH2Cl2, and DMSO were recorded vs. the saturated calomel electrode (SCE), showing that the E-1/2 value of 1 was more solvent dependent than those of 2-4, and that the difference in E-1/2 values among 2-4 was solvent independent, unlike those found between 1 and 2-4. This shows that 2-4 are much more reliable internal references for determining redox potentials than 1, but using data from this article, one can convert the literature values reported vs. 1 into values vs. 2, 3, or 4. The electrochemistry of 1 and 2 is all the more inhibited by polyamine dendrimers as the dendrimer generation is higher. On the other hand, ferrocenes or other iron sandwich compounds containing hydroxy groups can reestablish reversible cyclic voltammograms. It is shown, using a tetra(ferrocenylmethylamine), that this phenomenon is due to hydrogen bonding between the amido and phenol groups rather than bonding of hydroxy groups to the electrode surface. 

ferrocene; reference; electrochemistry; metallocene; sandwich complex; iron; dendrimer; passivation; hydrogen bond