A binaphthol-substituted tetrathiafulvalene with axial chirality and its enantiopure TCNQF4 charge-transfer salts
作者:Ali Saad、Olivier Jeannin、Marc Fourmigué
DOI:10.1039/c1nj20034h
日期:——
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.
Mixed‐valence dyadic [(TTF)2]+. (TTF=tetrathiafulvalene) species—the elementary building blocks of organic conductors—are usually too weakly associated to be observed in solution, unless covalently bound in dimers or physically constrained into a cage structure. We demonstrate here that a novel chiral tetrathiafulvalene functionalised with two 1,1′‐binaphthol units (1) is able to associate in solution