Decorating tetrathiafulvalene (TTF) with fluorinated phenyls through sulfur bridges: facile synthesis, properties, and aggregation through fluorine interactions.

Tetrathiafulvalene derivatives (TTF1-TTF9) bearing fluorinated phenyl groups attached through the sulfur bridges have been synthesized by employing a copper- mediated C-S coupling reaction of C6H5xFx I( x = 1, 2, 5) and a zinc-thiolate complex, (TBA)2(Zn(DMIT)2) (TBA = tetrabutyl ammonium, DMIT = 1,3-dithiole-2-thione-4,5-dithiolate), as the key step. Particularly, the selective synthesis of C6F5-sub- stituted (TTF8) and C6F4-fused (TTF9) TTFs from C6F5I is dis- closed. The physicochemical properties and crystal structures of these TTFs are fully investigated by UV/Vis absorption spectra, cyclic voltammetry, molecular orbital calculation, and single-crystal X-ray diffraction. The exchange of hydro- gen versus fluorine on the peripheral phenyl groups show a notable influence on both the electronic and crystallo- graphic natures of the resulting TTFs: 1) lowering both the HOMO and the LUMO energy levels, 2) modulating the elec- trochemical properties by regioselective and/or the degree of fluorination, 3) enhancing the driving forces of stacking by multiple fluorine interactions (F···S, CF···p/pF ,C F···FC, and CF···H). This work indicates that the decoration with fluorinated phenyls holds promise to produce functional TTFs with novel electronic and aggregation features.