Oligophenylene ethynylene

It has been reported that the electrical properties of single molecules incorporating redox groups (e.g. viologens [114, 119, 120, 123, 124], oligophenylene ethynylenes [122, 123], porphyrins [111, 126], oligo-anilines and thiophenes [116, 127], metal transition complexes [118,128-132], carotenes [133], ferrocenes [134,135],perylene tetracarboxylic bisimide [93, 136, 137] and redox-active proteins [138-143]), can be switched electrochemically. Such experiments, typically performed by STM on redox-active molecules tethered via Au-S bonds between a gold substrate and a tip under potential control, allow the possibility to examine directly the correlation between redox state and the conductance of individual molecules. 

T. Gu, D. Tsamouras, C. Melzer, V. Krasnikov, P. Gisselbrecht, M. Gross, G. Hadziioannou, J.-F. Nierengarten, Photovoltaic devices from fullerene oligophenylene ethynylene conjugates, Chem Phys Chem, vol. 3, pp. 124-127, 2002. 

A system analogous to the amphiphilic polythiophenes is based on oligophenylene ethynylene, which is turned into a facial amphiphilic polymer by the attachment of ammonium groups on one face and aliphatic tails on the... 

This modular methology involves the repetition of directed protection/cyclo-addition/deprotection steps, and allows for the synthesis of monodisperse dendritic oligophenylenes of the first (46a, 22 benzene rings) and second (46b, 62 benzene rings) generation [60]. Within the synthetic sequence, the authors made use of the different reactivities of protected and deprotected ethynylene functions within the key cycloadditon step. 

---