Inherently chiral thiophene-based electrode surfaces

The general strategy followed for “chiralizing” electroactive materials is to hang chiral pendants to the polyconjugated chain which assumes a form of chirality which is somewhat “reflected” from outside. The consequences of the diastereomeric interactions of this kind of materials with chiral species are generally modest, even though some exceptions are present in the chemical literature. In this context, we are currently developing electroactive materials in which the conducting polyconjugated chain is chiral by itself (inherently chiral), with no help from external chiral decorations, since chirality results from a tailored torsion internally produced in the oligothiophene backbone. It is expected that the enantiorecognition process directly effected by the chiral chain could be followed by relevant conformational modifications, in turn associated with significant variations in its electronic and electric properties. In particular we have recently developed and studied a purposedly non-planar, inherently chiral multithiophene-based monomer showing an intrinsically high ability for fast and regular electropolymerisation, and performing outstandingly as a 3D promoter building block in copolymerizations. The racemate of the new oligomer was resolved, the CD spectra of the antipodes being perfect mirror images. This allowed us to perform preliminary experiments of enantiopure TX electropolymerizations, followed by characterization of the resulting conducting films. The solid-state dichroism measurements point to the solid-state films fully retaining the dissimmetry of enantiopure monomers. The preliminary tests on this innovative surfaces will be reported and discussed.