Electrochemical activity of thiahelicenes: Structure effects and electrooligomerization ability

Thiahelicenes are polycondensed heteroaromatic molecules characterized by a chiral helix-like structure including multiple thiophene units, with a lowering effect on the oxidation potentials and a shrinking effect on the band gaps. As a consequence they can be regarded as electrochemically and optically active conducting materials, exhibiting interesting properties under electrical or magnetic polarization, and are under study for non-linear optics (NLO) applications. The present extensive investigation on 11 thiahelicenes with different chain length and functionalization (including the first example of a thiahelicene with perfluorinated alkyl chains) together with the precursor benzodithiophene provides a deep insight on the structure vs. electrochemical activity relationship within this attractive compound class, focusing on both electron transfer (ET) properties and oligomerization ability (hinging on free α positions on terminal thiophene groups).