Inherently Chiral Oligomers Based on Indole–Benzothiophene Core

Abstract

In recent years, transductors of chiral information based on conducting polymers have gained considerable attention. In particular, inherently chiral materials, which allow differentiation between the antipodes of a chiral analyte in terms of energetic variations, are highly desired. In this work, we successfully synthesized a novel inherently chiral oligomer based on an indole–benzothiophene core, namely, 2-([2,2′-bithiophen]-5-yl)-3-(2-([2,2′-bithiophen]-5-yl)benzo[b]thiophen-3-yl)-N-methylindole (BTIndT₄). The electrochemical characterization evidences a stabilization of electrogenerated radical cations due to the presence of the indole group, which guides the oligomerization, producing well-ordered polymeric matrices. Furthermore, the in situ electrochemical conductance analysis demonstrates a simultaneous intrachain and interchain transfer of charge carriers. Finally, the highly efficient enantiorecognition capabilities of the antipodes of the oligo-BTIndT₄ films toward the enantiomers of tryptophan and 3,4-dihydroxyphenylalanine (DOPA), as model chiral analytes, were demonstrated.