Halogen bonding, hydrogen bonding and fluorine segregation in conducting salts of novel halogenated tetrathiafulvalenes

Two different intermolecular interactions are described and analyzed in cation radical salts of functionalized tetrathiafulvalenes. On the one hand, the electrostatic nature of the CN⋯Hal interaction is demonstrated through the observed structural modifications, (i) when halogenated TTFs such as I-EDT-TTF and I2-EDT-TTF are engaged with cyano anions where a strengthening of the interaction is noted, or (ii) when EDT-TTF-CN is engaged with halogenated anions where the CN⋯Hal interaction is totally suppressed. other hand, we took advantage of the absence of interactions experienced by aliphatic fluorinated molecules to investigate the structural and electronic properties of fluorinated tetrathiafulvalenes such as the bis(difluoropropylenedithio)tetrathiafulvalene. Its synthesis, electrochemical and structural properties will be described as well as different salts with linear (ICl2−) and complex (Mo6Cl142−) anions. Fluorine–fluorine segregation effects combined with C–H⋯Hal hydrogen bonds lead to striking layered structures with fluorinated bilayers while an organic–inorganic segregation is also retained with the conducting 4:1 salt of the unsymmetrically substituted (difluoropropylenedithio)tetrathiafulvalene with Mo6Cl142−.