Structure and electrochemistry of a tetrakis(ferrocenecarboxylato)diruthenium(II,III) diadduct: evidence for ferrocenyl–ferrocenyl communication

1-Propanol and ethanol adducts of tetrakis(ferrocenecarboxylato)diruthenium(II,III) hexafluorophosphate have been synthesized and the 1-propanol diadduct has been characterized by X-ray crystallography. The cyclopentadienyl rings of all four ferrocenyl groups showed on average a 13° deviation from the eclipsed conformation. Cyclic voltammetry measurements in 1,2-dichloroethane show an irreversible RuIIIRuII/RuIIRuII reduction and four partially superimposed one-electron ferrocenyl-centred electron transfer processes. The existence of ferrocenyl-based mixed-valent intermediate states posessing FeIII and FeII sites are implied by the splitting of the ferrocenyl wave into two observable cathodic and anodic peaks. The first cathodic wave shows typical desorption behaviour. Osteryoung Square Wave Voltammetry (OSWV) supports the above findings.