Intermolecular interactions and charge transfer in the 2:1 tetrathiafulvalene bromanil complex, (TTF)2-BA

The crystal structure of the 2:1 charge-transfer complex of tetrathiafulvalene [2,2'-bis(1,3-dithiolylidene)] and bromanil (tetrabromo-1,4-benzoquinone) [(TTF)(2)-BA, (C6H4S4)(2)-C6Br4O2] has been determined by X-ray diffraction at room temperature, 100 and 25 K. No structural phase transition occurs in the temperature range studied. The crystal is made of TTF-BA-TTF sandwich trimers. A charge-transfer estimation between donor and acceptor (0.2 e) molecules is proposed in comparison to the molecular geometries of TTF-BA and TTF and BA isolated molecules. Displacement parameters of the molecules have been modeled with the TLS formalism.