Influence of the regioregularity on the chiral supramolecular organization of poly(3-alkylsulfanylthiophene)s

Abstract

The manuscript investigates the influence of the regioregularity (RR) of poly(3-alkylsulfanylthiophene)s (P3AST) on their properties. Therefore, a series of P3ASTs (P1–P5) with different RR were synthesized using a combination of a “reversed McCullough method” and the GRIM method. The degree of RR was determined by ¹H NMR spectroscopy. A detailed chiroptical study in good solvent, poor solvent and film was performed, which revealed that the tendency to form chiral supramolecular aggregates clearly depends on the RR, but that the relation is not simply continuously increasing. Instead, the strongest effects were observed in P3ASTs with high, but not 100% RR. As a consequence, a similar behaviour can be expected for a regioregular and a particular irregular P3AST. This hypothesis was tested on a regioregular and an irregular P3AST that proved to have similar chiroptical properties in a previous study. Their properties in the solid state were investigated in detail using STM and AFM.