Synthesis and properties of oligo(2,5-thienylene-ethynylene)s

Abstract

Oligo(2,5-thienylene-ethynylene)s [OTE] are a class of conjugated oligomers with a high shape- persistence as rigid rods, which give these "molecular wires"interesting properties in materials science. The synthetic approach to OTEs is based on iterative Sonogashira-Hagihara reactions and possible end-cappings with certain functional groups or sub-structures. Special attention is focused on systems with terminal donor-acceptor substitution DAOTEs which exhibit an unusual absorption behavior. Increasing numbers of repeating units lead in OTEs to a convergent bathochromic effect; on the contrary, hypsochromic shifts can be observed for DAOTEs with a strong push-pull effect.