Ferrocenyl Dendrimers Based on Octasilsesquioxane Cores

Hydrosilylation reactions of two octasilsesquioxane dendritic cores containing terminal vinyl groups with bis­(ferrocenyl)­methylsilane (<b>1</b>) give dendrimers functionalized with 16 (<b>G1-Fc</b>_<b>16</b>) and 32 (<b>G2-Fc</b>_<b>32</b>) 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 <b>G1-Fc</b>_<b>16</b> and <b>G2-Fc</b>_<b>32</b> was studied by TGA techniques. The redox activity of the ferrocenyl centers in <b>G1-Fc</b>_<b>16</b> and <b>G2-Fc</b>_<b>32</b> has been characterized by cyclic voltammetry and square wave voltammetry in dichloromethane containing [<i>n</i>-Bu₄N]­[PF₆] as electrolyte support. The solution voltammetric studies of the dendrimers <b>G1-Fc</b>_<b>16</b> and <b>G2-Fc</b>_<b>32</b> 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

Synthesis and Electrochemical Anion-Sensing Properties of a Biferrocenyl-Functionalized Dendrimer

The synthesis and electrochemical anion-sensing properties of a diaminobutane poly­(propyleneimine) dendrimer functionalized with biferrocenyl units <b>2</b> are presented. The redox activity of the ferrocenyl centers in <b>2</b> has been characterized by cyclic voltammetry. Cyclic and square wave voltammetric investigations demonstrate that tetraferrocenyl compound <b>2</b> and the reference compound <b>1</b> show electrochemical anion-sensing action: they display a cathodic shift of the ferrocene–ferrocenium redox couple with dihydrogenphosphate and hydrogensulfate anions in solution and immobilized onto electrode surfaces

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

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