Stabilizing Radical Cation and Dication of a Tetrathiafulvalene Derivative by a Weakly Coordinating Anion

After
the chemical oxidation of the neutral tetrakis­(methylthio)­tetrathiafulvalene
(TMT-TTF, 1) by specific oxidation agents with weakly
coordinating anion, [Al­(ORF)4]− [ORF = OC­(CF3)3], the radical cation
TMT-TTF•+ (1•+) and dication TMT-TTF2+ (12+) were successfully stabilized and isolated. All the
compounds are well-soluble in some solvents and have been systematically
investigated by absorption spectra, 1H NMR, electron paramagnetic
resonance (EPR) measurements. Their crystal structures and electronic
properties have been studied in conjunction with theoretical calculation.
The synthetic approach for chemical oxidation by specific salts of
weakly coordinating anions is useful for stable radical cations of
tetrathiafulvalene (TTF) and its derivatives in both solution and
solid state, which will extend the further research, including structure–property
relations on stable radicals for TTF derivatives and new functional
materials based on them.