Effects of Structural Factors on the π-Dimerization and/or Disproportionation of the Cation Radical of Extended TTF Containing Thiophene-Based π-Conjugated Spacers

Chalcogen-bond driven molecular recognition at work

“…For instance, the X-ray structure analysis of 69 revealed the presence of intramolecular O…S and S…S EBIs (dO…S = 2.914 Å; dS…S = 3.098 Å, Figure 29c), which forced the π-conjugated rings to lye coplanar. [119] This locking effect has also been used in ifferent systems, including radical cation salts, [120][121][122] tetrathiafulvalene-bithiophene hybrid conjugated systems, [123,124] and small molecules constituted by thiadiazole and thiophene moieties. [125][126][127] Thin films containing the fibres have been also investigated by small angle reflection of X-ray.…”

Extended benzodifuran–thiophene systems connected with azomethine junctions: synthesis and electronic properties

“…For 1b-d, the DE p values are smaller than 60 mV expected for a mono-electronic process and we can stipulate that the oxidation of compounds 1b-d gives directly the dication state. 28,29 By comparison with the diamino benzodifuran derivatives, the lengthening of the conjugated chain with the azomethine junctions isoelectronic of ethylenic bonds 17 leads to a large electronic delocalization. 30,31 Thus thiophene-imine-benzodifuran-imine-thiophene systems correspond to a large extended conjugated system favouring the access to the dication state.…”

Delocalization tunable by ligand substitution in [L2Al]n−complexes highlights a mechanism for strong electronic coupling

“…7,8 For example, triarylamine compounds are only synthesized with R ¼ OMe protecting groups in the para position to avoid coupling of the two cationic radicals tail to tail, 7,9 and dithiafulvenyl compounds undergo dimerization of the MV radical cations when substituted with EW groups. 10,11 Disproportionation of the MV state has been observed for MV naphthidines with ED groups, whereas EW groups, such as uorine favored formation of the oxidized dications. 12 Although limited by synthetic challenges in many instances, the effect of ED or EW substitution on organic MV systems including phenylenediamine, 13 bis(triarylamine), 14 or naphthidine radical cations, 12 has been explored: in all cases the MV states are strongly coupled "charge resonance" compounds and the coupling is not signicantly affected by substitution of ED and EW substituents on the end-groups.…”