Decorating Tetrathiafulvalene (TTF) with Fluorinated Phenyls through Sulfur Bridges: Facile Synthesis, Properties, and Aggregation through Fluorine Interactions. Issue 31 (30th June 2014) - Lu, Xiaofeng
Abstract 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 C6H5−xFxI (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‐substituted (TTF8) and C6F4‐fused (TTF9) TTFs from C6F5I is disclosed. 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 hydrogen versus fluorine on the peripheral phenyl groups show a notable influence on both the electronic and crystallographic natures of the resulting TTFs: 1) lowering both the HOMO and the LUMO energy levels, 2) modulating the electrochemical properties by regioselective and/or the degree of fluorination, 3) enhancing the driving forces of stacking by multiple fluorine interactions (F⋅⋅⋅S, CF⋅⋅⋅π/πF, CF⋅⋅⋅FC, and CF⋅⋅⋅H). This work indicates that the decoration with fluorinated phenyls holds promise to produce functional TTFs with novel electronic and aggregation features.