Chiral Bis(tetrathiafulvalene)-1,2-cyclohexane-diamides

Chiral bis(TTF) diamides have been obtained in good yields (54-74%) from 1,2-cyclohexane-diamine and the corresponding TTF acyl chlorides. The (R,R)-1 and (S,S)-1 enantiomers have been characterized by circular dichroism and the racemic form by single-crystal X-ray diffraction. The neutral racemic bis(TTF)-diamide shows the formation of a pincer-like framework in the solid state, thanks to the intramolecular S···S interactions. The chemical oxidation in a solution using FeCl₃ provides stable oxidized species, while the electrocrystallization experiments provided radical cation salts. In particular, single-crystal resistivity measurements on the racemic donor with AsF₆^- as a counterion demonstrate semiconductor behavior in this material. The DFT and TD-DFT calculations support the structural and chiroptical features of these new chiral TTF donors.