Synthesis and oxidation of two ferrocene-capped cobalt clathrochelates in methylene chloride

Abstract

The synthesis and oxidation of two new ferrocene-caped cobalt clathrochelates are described. The compounds Co(nox) 3 (B-(cp)Fe(cp)) 2 and Co(dmg) 3 (B(cp)Fe(cp)) 2 (nox is 1,2-cyclohexanedione dioximate (2-), dmg is dimethylglyoximate (2-), and cp is cyclopentadienide) can each proceed through a total of six species when a three-electron oxidation of the fully reduced forms occurs. A thermodynamic scheme has been developed to describe the oxidation process. The observed spectrophotometric behavior upon oxidation cannot be adequately explained by assigning one reduction potential to cobalt and one to the two iron centers. Instead, a minimum of three potentials is required. Reduction potentials for the six species, relative to ferrocene, are presented. These potentials show only slight temperature and added salt dependencies. Possible modes of interaction between the metal sites are discussed