Ferrocenes Bearing Highly Extended π Systems with Nitrile, Nitro, and Dimethylamino End Groups

Oligophenylene-ethynylenes are a popular class of molecular wires for molecular electronics. Replacement of some, not all, of the 1,4-phenylene units by 1,1-ferrocenylene moieties generates less rigid entities with a limited conformational flexibility. Within this concept, the syntheses of some 1,1-disubstituted ferrocenes that bear arylethynyl or 4-(arylethynyl)phenyl substituents is presented. In contrast to related compounds with sulfur end groups that were prepared previously, the versions presented here have nitrile end groups, which, according to reported precedence, may serve as points of attachment to gold surfaces. A crystal structure analysis of an unusual diferrocenylethyne derivative is included. In addition, one representative with a push-pull disubstitution that has a nitro and a dimethylamino end group is presented. Many of the prepared compounds have been characterized by cyclic voltammetry.