Decorating Tetrathiafulvalene (TTF) with Fluorinated Phenyls through Sulfur Bridges: Facile Synthesis, Properties, and Aggregation through Fluorine Interactions

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 C6 H5-x Fx 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 C6 F5 -substituted (TTF8) and C6 F4 -fused (TTF9) TTFs from C6 F5 I 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.

Donor–acceptor type co-crystals of arylthio-substituted tetrathiafulvalenes and fullerenes

“…As reported, the π-extended TTFs (exTTF) can encapsulate fullerenes in solution, and form the inclusion complex with fullerenes as well [ 28 – 37 ]. Very recently, we have disclosed a facile approach toward the arylthio-substituted TTFs (hereafter denoted as Ar-S-TTF) [ 60 – 62 ], which bear four aryl groups on the peripheral positions of the TTF core through the sulfur bridges. The Ar-S-TTF molecules are size and shape matched for fullerenes (C 60 /C 70 ), and the peripheral aryls show large rotational freedom that could adjust their spatial alignment to adapt to the environmental variations [ 61 ].…”

Copper ion salts of arylthiotetrathiafulvalenes: synthesis, structure diversity and magnetic properties

“…The donor molecules ( 1 – 7 , Scheme 1) were synthesized according to our previous report [37–38], and their electrochemical activities as well as the crystal structures have been fully elucidated [38–39]. Since the redox potentials of TTFs are very important in the formation of complexes, particularly on the charge-transfer degree, the first ( E 1/2 1 ) and the second ( E 1/2 2 ) redox potentials of 1 – 7 are summarized in Table 1.…”

“…Recently, we have disclosed a facile approach toward Ar-S-TTFs [37]. Crystallographic investigations indicate that Ar-S-TTFs show various molecular geometries and packing structures depending on the nature of the peripheral aryls [38–39]. …”

“…Most Ar-S-TTFs possess redox potentials higher than that of bis(ethylenedithio)-TTF (BEDT-TTF) [33–39]. Consequently, the complexes of Ar-S-TTFs with electron acceptors such as fullerenes [40–41] and TCNQ [42] show a neutral ground state.…”

Organic–Inorganic Hybrid Clusters Assembled from Phosphomolybdate Anions and Thioarylated Tetrathiafulvalenes with Diversiform Electron States and Configurations

“…THF and acetonitrile (CH 3 CN) were dried with CaH 2 and stored under N 2 atmosphere. Ar‐S‐TTFs 1 – 6 were synthesized according to our previous report …”