A sulfur-rich pi-electron acceptor derived from 5,5 '-bithiazolidinylidene: charge-transfer complex vs. charge-transfer salt

Y Le Gal (1) , M Rajkumar (1) , A Vacher (1) , V Dorcet (1) , T Roisnel (1) , M Fourmigue (1) , F Barriere (1) , T Guizouarn (1) , D Lorcy (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

Novel pi-electron acceptors are still highly desirable for the formation of conducting salts or as n-dopable semiconductors. We describe here two synthetic approaches to substitute a dicyanovinylidene group, C=C(CN)(2) to a thioketone (C=S) in the recently described DEBTTT acceptor where DEBTTT stands for (E)-3,3'-diethyl-5,5'-bithiazolidinylidene-2,4,2',4'-tetrathione. These electron withdrawing groups enhance the electron accepting ability as demonstrated through electrochemical investigations, without hindering the formation of short intra-and intermolecular S center dot center dot center dot S contacts in the solid state. Association of this acceptor 1 with tetramethyltetrathiafulvalene (TMTTF) and decamethylferrocene (Fe(Cp*)(2)) afforded 1 : 1 adducts which were analyzed by single crystal X-ray diffraction. Combined with vibrational and magnetic properties, it appears that [TMTTF][1] behaves as a neutral charge-transfer complex while [Fe(Cp*)(2)][1] is an ionic salt. The concentration of the spin density on the exocyclic sulfur atoms in 1(-center dot) favors the setting of direct anti-ferromagnetic interactions in [Fe(Cp*)(2)][1]

Keywords: DITHIADIAZAFULVALENES; TETRATHIAFULVALENE; DITHIOLENE; DESIGN; SERIES; METAL

Domains: Chemical Sciences; Organic chemistry

Y Le Gal, M Rajkumar, A Vacher, V Dorcet, T Roisnel, et al.. A sulfur-rich pi-electron acceptor derived from 5,5 '-bithiazolidinylidene: charge-transfer complex vs. charge-transfer salt. CrystEngComm, 2016, 18 (21), pp.3925--3933. ⟨10.1039/c6ce00772d⟩. ⟨hal-01338503⟩