Ferrocenyl Dendrimers Based on Octasilsesquioxane Cores

Hydrosilylation reactions of two octasilsesquioxane dendritic cores containing terminal vinyl groups with bis­(ferrocenyl)­methylsilane (1) give dendrimers functionalized with 16 (G1-Fc₁₆) and 32 (G2-Fc₃₂) interacting ferrocenyl units. Characterization of the dendrimers by ¹H, ¹³C­{¹H}, and ²⁹Si­{¹H} NMR spectroscopy as well as mass spectrometry supports their assigned structures. The thermal behavior of dendrimers G1-Fc₁₆ and G2-Fc₃₂ was studied by TGA techniques. The redox activity of the ferrocenyl centers in G1-Fc₁₆ and G2-Fc₃₂ has been characterized by cyclic voltammetry and square wave voltammetry in dichloromethane containing [n-Bu₄N]­[PF₆] as electrolyte support. The solution voltammetric studies of the dendrimers G1-Fc₁₆ and G2-Fc₃₂ exhibit the pattern of communicating ferrocenyl sites with two distinct, separated oxidation waves. The dendrimers were also deposited on electrode surfaces and the electrodes investigated via CV, showing formation of electroactive films with promising results for the use of these materials in the development of biosensors.