Electrochemical activity of thiahelicenes: Structure effects and electrooligomerization ability

Ternary thiophene–X–thiophene semiconductor building blocks (X=fluorene, carbazole, phenothiazine): Modulating electronic properties and electropolymerization ability by tuning the X core

“…polymerization, while the CV features of the monomers in solution are nearly coincident, could be a consequence of the increasing length of the aliphatic chains resulting in (i) increasing solubility of the oligomers, and/or (ii) increasing difficulty in 3D ordering during film formation (also resulting in weaker p stacking effects), and/or (iii) decreasing probability of effective encounters between radical cations to give coupling and therefore polymerization. This is fully consistent with former observations by some of us in a comparative study on substituted thiahelicenes [70].…”

“…This is consistent with an EC mechanism (electron transfer followed by chemical reaction), resulting in a higher peak with respect to a E rev (reversible monoelectronic electron transfer) case [68], including the particular cases of oligomerization [69] and polymerization [70] . Therefore the above feature does not necessarily point to the two terminal thiophene positions being independent and, as a consequence, equivalent, which would result, of course, in a monoelectronic peak of double height.…”

Towards Molecular Design Rationalization in Branched Multi‐Thiophene Semiconductors: The 2‐Thienyl‐Persubstituted α‐Oligothiophenes

“…One possible explanation for the gradual decrease in the T'X Y polymerization ability with increasing n could be found, in principle, in the increased solubility resulting from increasing molecular branching, as observed, for example, in a recent study concerning thiahelicenes; [21] however, in the present case this explanation would not justify the reversible peak shape. In other words, in the case of formation of a soluble coupling product the irregular return peak corresponding to the redox-active film could disappear, but the oxidation peak would maintain an irreversible shape.…”

An effective multipurpose building block for 3D electropolymerisation: 2,2′-Bis(2,2′-bithiophene-5-yl)-3,3′-bithianaphthene

“…Moreover, inherently asymmetric molecules (such as, e.g. thiahelicenes [21]) open up a new strategy to prepare asymmetric superior aggregates for the nonlinear optics (NLO) applications.…”