New Soluble Bis[nona-, octa-, and pentamethylferrocenes] as “Molecular Wires” with a Metal-to-Metal Distance of up to 40 Å

Abstract

Methylated ferrocenes are useful building blocks for novel materials in molecular electronics with advantageous properties in comparison to normal ferrocene derivatives. The presence of nine, eight, or five methyl substituents leads to (i) a decrease in oxidation potential, (ii) amplified donor capacity with correspondingly increased stability of the ferrocenium salts, and, most significantly, (iii) increased solubility. A modular synthetic approach based on standard Wittig chemistry affords π-conjugated soluble nona-, octa-, and pentamethylated biferrocenes, bridged by up to five vinylene−phenylene subunits. These biferrocenes with spacers are “molecular wires” with a metal-to-metal distance of up to 40 Å and an effective conjugation pathway of up to 50 Å.