NEW SOLUBLE BIS[NONA-METHYLFERROCENES, OCTA-METHYLFERROCENES, AND PENTAMETHYLFERROCENES] AS MOLECULAR WIRES WITH A METAL-TO-METAL DISTANCE OF UP TO 40-ANGSTROM

Methylated ferrocenes are useful building blocks for navel materials i n molecular electronics with advantageous properties in comparison to normal ferrocene derivatives. The presence of nine, eight, or five met hyl substituents leads to (i) a decrease in oxidation potential, (ii) amplified donor capacity with correspondingly increased stability of t he ferrocenium salts, and, most significantly, (iii) increased solubil ity. A modular synthetic approach based on standard Wittig chemistry a ffords pi-conjugated soluble nona-, octa-, and pentamethylated biferro cenes, bridged by up to five vinylene-phenylene subunits. These biferr ocenes with spacers are ''molecular wires'' with a metal-to-metal dist ance of up to 40 Angstrom and an effective conjugation pathway of up t o 50 Angstrom.