Synthesis and Supramolecular Organization of Regioregular Polythiophene Block Oligomers

The self-assembly of functional polythiophenes was studied by a bottom-up approach from molecule to polymer. The synthesis and the X-ray structure of 2,5-dibromo-3-styryl and 3-2',3',4',5',6'-pentafluorostyryl-thiophenes revealed a supramolecular arrangement controlled by pi-pi interactions between the aromatic rings. A [2 + 2] photocyclization reaction in the solid state of (E)-1-2',5'-dibromo-3'-thienyl-2-phentafluorophenylethene triggers the formation of a rare cycloadduct comparing thiophene rings. The X-ray analysis confirmed its re11 stereochemistry. The synthesis of P3HT-b-P3ST and P3HT-b-P3STF block oligomers was acheived by a GRIM method in good yields. An indirect proof of well-defined nanostruactured organization was provided by the partial photocyclization of pendant styryl moieties under UV irradiation.