Inherently Chiral Organic Semiconductors

Chirality is generally introduced in polyconjugated electroactive materials by attaching chiral pendants, invariably characterized by the presence of carbon stereocenters, to the conjugated backbone through suitable linkers. Our research is focused to develop a new class of chiral organic electroactive polymers in which chirality results from a torsion internally produced in the backbone of the polymerogenic unit 1 by the presence of a suitably substituted atropisomeric biheteroaromatic scaffold. The stereogenic core is tailored so as to conjugatively interconnect the two bithiophene termini and the C2 symmetry of the monomers assures the perfect constitutional regularity of the resulting polymers. The monomers synthesized on large scale till now are characterized by the atropisomeric scaffold of the 3,3’-bithianaphtene. In this communication two new monomers (1b and 1c), specifically designed in order to obtain soluble polymers more easily processable than (1a)1, will be presented. The synthesis, the resolution, the optical, the photophysical and the electrochemical properties of these monomers and of the corresponding polymers will be discussed.