Intramolecular electronic interactions in conjugated ferrocene-pi-extended-tetrathiafulvalene donor-pi-donor molecular hybrids

The synthesis of new hybrid ferrocene and pi -extended tetrathiafulvalene ( TTF) donor(1)-pi -donor(2) molecular assemblies 16a-c has been carried out by a Wittig-Horner reaction of the respective phosphonate esters 15a-c with 2-(2-ferrocenylvinyl)-9,10-anthraquinone (18) prepared by olefination of f errocenecarboxaldehyde (14) and the anthraquinone phosphonium salt 17. Elec trochemical studies show that the D-1-pi -D-2 (D = donor) molecular assembl ies 16a-c essentially retain the redox characteristics of both ferrocene an d the pi -extended TTF components and the effects of solvent, temperature, scan rate, and working electrode are significant. Most importantly, pronoun ced intramolecular electronic interactions between the two donor moieties w ere observed by cyclic voltammetry and Osteryoung square wave voltammetry i n both the ground and charged states. Semiempirical calculations support th e electrochemical observations.