Tetrathiahelicenes : a never-ending research

Helicenes are intrinsically chiral ortho-annulated (hetero)aromatic rings having screw-shaped structures. These curved organic systems represent an intriguing class of π-molecules that provide unique opportunities for applications in a wide range of areas, including materials sciences, chiroptical devices, and asymmetric synthesis.1 Among helicenes, thiahelicenes are unique thanks to the presence of thiophene rings, which confer special chemical, geometric, and electronic features.2 During the years, we have contributed to the set up of synthetic methodologies and functionalization of tetrathiahelicene (7-TH) derivatives (Figure 1), a class of configurationally stable heterohelicenes, potentially very interesting for applications in optoelectronics,3 catalysis,4 and biology.5 These systems can be easily functionalized at the 2 and 13 positions of the two terminal thiophene rings, allowing the modulation of the chemical and physical properties.