Charge transfer complexes and radical cation salts of chiral methylated organosulfur donors

International audienceThe single crystal X-ray structure of the all-axial conformer of the (R, R, R, R) enantiomer of the chiral donor tetramethyl-BEDT-TTF (TM-BEDT-TTF) was described and compared to the all-equatorial conformer. (S, S, S, S)-Tetramethyl-BEDT-TTF formed crystalline 1 : 1 complexes with TCNQ and TCNQ-F-4, as well as a THF solvate of the TCNQ complex. Donors bis((2S, 4S)-pentane-2,4-dithio) tetrathiafulvalene and (ethylenedithio)((2S, 4S)-pentane-2,4-dithio) tetrathiafulvalene, which contain seven-membered rings bearing chirally oriented methyl groups, only formed complexes with TCNQ-F4. The TCNQ-F4 complexes contain planar organosulfur systems, in contrast to the TCNQ complexes in which there is minimal charge transfer. A variety of crystal packing modes were observed. Electrocrystallization experiments with both enantiomers and the racemic form of tetramethyl-BEDT-TTF afforded mixed valence radical cation salts with the AsF6 and SbF6 anions formulated as (TM-BEDT-TTF)(2)XF6 (X = As, Sb). Electrical conductivity was only found in one charge transfer complex, while the radical cation salts are all semiconducting