Synthesis and Electropolymerization of Hexadecyl Functionalized Bithiophene and Thieno[3,2-b]thiophene End-Capped with EDOT and EDTT Units

The synthesis of three novel thiophene-based conjugated molecules (1−3) is presented. We report the electronic and redox properties of these compounds along with the corresponding electrochemically prepared polymers. The structures of compounds 1 and 2 have been confirmed by single-crystal X-ray diffraction studies. Noncovalent S···O interactions in 1 act to hold the molecule in a planar conformation and this is in stark contrast to the twisted nature of the 3,4-ethylenedithiothiophene (EDTT) analogue. The degree of planarity within the molecules dictates the effective conjugation length within the materials and also the packing of the molecules in the solid state. CGL-TOF studies give hole mobilities up to 4 × 10−5 cm2 V−1 s−1 for compound 1 and 1.5 × 10−5 cm2 V−1 s−1 for 2.