All-Thiophene-Based Double Helix: Synthesis, Crystal Structure, Chiroptical Property and Arylation.

The all-thiophene-based double helix was designed and prepared originally from the selective deprotonation of cyclooctatetrathiophene (tetra[3,4]thienylene, ) and following the Negishi coupling reaction with 3,3'-bithiophene. The X-ray crystallographic studies revealed that has a double-helical scaffold. The arylations including tetraphenylation and tetrathienylation were efficiently employed to replace the four α-protons of the central of with phenyl and thiophenyl groups via cross-coupling reactions. The chiral resolution of - was fulfilled via chiral high-performance liquid chromatography, and the chiroptical properties were characterized by circular dichroism spectra and optical rotation. Ultraviolet-visible absorption and fluorescence behaviors of and its arylation products were also characterized to describe the extended conjugated scaffold.