Synthesis, Single Crystal, and Physical Properties of Asymmetrical Thiophene/Selenophene-Fused Twistacenes.

Two asymmetrical twistacenes, PyPT and PyPS, have been synthesized and characterized. Single crystal Xray analyses show that both of them have twisted structures with a torsion angle of 26.65 degrees for PyPT and 26.59 degrees for PyPS measured between plane C5-C23-C25 and plane C13-C15-C26. The thiophene/selenophene-fused acenes emit blue fluorescence with quantum yields of 0.39 for PyPT and 0.04 for PyPS in organic solvents, whereas the all-carbon molecule HBP emits green fluorescence. Meanwhile, PyPT and PyPS show a similar reversible oxide procedure with the onset potentials of 0.73 and 0.72 V, respectively. In addition, PyPT and PyPS can self-assemble to form nanoparticles in a mixture of THF/H2O through re-precipitation method.