Resumen de Synthesis, electronic properties and applications of π-conjugated oligomers based on thiophene
π-conjugated oligomers are the shorter version of π-conjugated polymers, composed of the same scaffolds and presenting some advantages in comparation with the macromolecules. Indeed, the oligomers are smaller, more processable and they have a known structure. Their properties can be tailored by simple changes in the structure of the monomer unit that will be repeated in the chain. Finally, the properties of the whole molecule can be tailored mainly attending to the length of the molecule.
Conjugated oligomers are used as molecular wires because of their unidimensional structure and as dyes as they present good absorption in the visible part of the spectra.
Among conjugated oligomers, those composed of monomers based on thiophene units have attracted attention in the last decade. Thiophene is an electron rich molecule, available to be modified by chemical functionalization by diverse synthetic paths. Several modifications that changes the planarity, solubility or aromaticity of the molecule have been proposed. Oligothienilenevinylenes, oligocyclopentadithiophenevinylenes are a good example of this research.
In this work, we study the electronical properties of thiophene based, π-conjugated molecules, when they are act as molecular wires between electrodes, being part of dyes in acceptor-donor-acceptor triads and when they form supramolecular aggregates. The aromaticity of the thiophene is changed into non-aromatic by chemical oxidation of the sulfur is studied as well. The electronical properties of this new oligomers is compared with no oxidized ones and the effect of the aromaticity is addressed.
