Bis-ferrocene derivatives of bridged calix[4]arenes: syntheis, X-ray crystal structure and electrochemical properties

The reaction of chlorocarbonylferrocene (2) with bridged calix[4]arene macrocyclic compounds, in which two opposite para-positions are connected by an additional aliphatic chain where n = 5 (1a) or n = 8 (1b) respectively, gave the corresponding new redox-active bis-ferrocene derivatives of bridged calix[4]arenes, 3a and 3b. An X-ray diffraction study of 3a shows that the caliz[4]arene has a cone conformation in which the two ferrocene substituents are located on the phenolic units connected to each other by the aliphatic chain bridge. Cyclic voltammetric and coulometric studies in dichloromethane reveal that 3a and 3b undergo reversible two electron oxidations at + 0.90 V (versus SCE), sug…