Synthesis and Electrochemistry of ((Diferrocenylsilyl)propyl)- and ((Triferrocenylsilyl)propyl)triethoxysilanes

Triferrocenylsilane 2 was synthesized. Hydrosilylation reactions employing allyltriethoxysilane and diferrocenylmethylsilane (1) and triferrocenylsilane (2) yielded new ferrocenyltriethoxysilane compounds functionalized with two (3) and three (4) interacting ferrocenyl units, respectively. Characterization of 2 and the ethoxysilane derivatives 3 and 4 by elemental analysis, 1H, 13C­{1H}, and 29Si­{1H} NMR spectroscopy, and mass spectrometry supports their assigned structures. The crystal structure of 2 has been determined by a single-crystal X-ray diffraction study. The redox activity of the ferrocenyl centers in 2–4 has been characterized by cyclic voltammetry and square wave voltammetry in dichloromethane containing [n-Bu4N]­[PF6] or [n-Bu4N]­[B­(C6F5)4] as electrolyte support. Voltammetric studies of 2–4 in solution exhibit the pattern of communicating ferrocenyl sites with two or three distinct, separated oxidation waves. Platinum oxide surfaces are covalently modified by redox-active 3 and 4.