Ferrocenyl Dendrimers with Ionic Tethers and Dendrons

Whereas covalently constructed dendrimers are very numerous, there are only a few examples of dendrimers based on ionic bonds with tethers or dendrons. Here such constructions were designed in order to examine their physicochemical consequences: in particular, the electrochemical and redox properties. Two series of secondary polyamine dendrimers containing ferrocenyl and octamethylferrocenyl were synthesized by condensation of polyamine dendrimers, obtained by reduction of the polyazide dendrimers by LiAlH4 or NaBH4 with ferrocenyl aldehyde or octamethylferrocenyl aldehyde, followed by reduction of the resulting polyimine dendrimers. Primary and secondary ferrocenyl polyammonium dendrimer salts have been synthesized by quaternization of the dendritic amines including ferrocenyl secondary polyamines by reaction with a triferrocenyl dendron containing a carboxylic acid as the focal point. Cyclic voltammetry data show the electrostatic effect of the intradendritic secondary ammonium groups and the distinction between intradendritic and peripheral ferrocenyl groups.