A binaphthol-substituted tetrathiafulvalene with axial chirality and its enantiopure TCNQF4 charge-transfer salts

Ali Saad (1) , Olivier Jeannin (1) , Marc Fourmigué (1)

1 ISCR - Institut des Sciences Chimiques de Rennes

A chiral tetrathiafulvalene (1) bearing a binaphtholdimethylene moiety on one side, an ethylenedithio substituent on the other side, is prepared from atropoisomeric (R)-, (S)- and racemic (R,S)-binaphthol. Its oxidation potential (0.49 V vs. SCE) allows for its oxidation with TCNQF4. Crystal structures of the neutral racemic (R,S)-1 and enantiopure (R)-1 were determined together with those of the enantiopure charge-transfer salts formulated as [(R)-1][TCNQF4]*CH2Cl2 and [(S)-1][TCNQF4]*CH2Cl2, the first enantiomeric salts of chiral TTFs with axial chirality. Despite the peculiar geometry adopted by the binaphthyl moieties in the constrained ten-membered ring in 1, stacking of the donor molecules is observed, both in the neutral state and in the TCNQF4 charge transfer salts where the (1)+˙ and (TCNQF4)−˙ radical species are associated, respectively, into [(1)2]2+ and [(TCNQF4)2]2− homodyads, both in their singlet state.

Domaines: Chimie organique

Ali Saad, Olivier Jeannin, Marc Fourmigué. A binaphthol-substituted tetrathiafulvalene with axial chirality and its enantiopure TCNQF4 charge-transfer salts. New Journal of Chemistry, 2011, 35, pp.1004-1010. ⟨10.1039/c1nj20034h⟩. ⟨hal-00615256⟩