1,1′-Diaryl-Substituted Ferrocenes: Up to Three Hinges in Oligophenyleneethynylene-Type Molecular Wires

Molecular wires of the oligophenyleneethynylene (OPE)type are potentially rigid entities, The idea of the work reported herein was to replace some, not all, of the phenylene moieties with ferrocene units, thereby introducing limited conformational flexibility with the ferrocene units acting as hinges as a consequence of the facile rotation around the Cp-Fe-Cp axis. In this context, the syntheses of a number of 1,1'-diaryl-disubstitued ferrocene building blocks are described. The new terminal diynes 22 and 24 were used to construct the first representatives of ferrocene-based molecular wires with three ferrocene hinges. The study includes an X-ray Structure analysis of the thiophene-based diyne 24 as well as cyclovaltammetric analyses of a number of the compounds prepared.