Structural Relations In (1:1) And (2:1) Cyanobenzene-Ethylenedithio-Ttf Radical Salts; The Role Of C N Center Dot Center Dot Center Dot H Interactions

Four salts of the dissymmetric TTF-derivative 4-cyanobenzene-ethylenedithio-tetrathiafulvalene (4-CNB-EDT-TTF) with different anions, namely (4-CNB-EDT-TTF)A with A = ClO4 (1), BF4 (2) and (4-CNB-EDT-TTF)(2)[M(mnt)(2)] with M = Ni (3) and Au (4), were obtained by electrocrystallization and characterized by single-crystal X-ray diffraction, magnetic susceptibility and electrical conductivity measurements in comparison with the analogues based on the donor 5-CNB-EDT-TTF. All the compounds present dimerization of the donor units. Compounds 1 and 2 are isomorphous with a crystal structure characterized by slipped head to tail donor dimer stacks segregated from anion columns. Compounds 3 and 4 are isostructural with a crystal structure characterized by alternated stacks of head to tail donor dimers and acceptors. In spite of the different structural types and stoichiometries, all of these compounds have C N center dot center dot center dot H pairing interactions associated with R-2(2)(8), R-4(2)(8), R-2(2)(10), and R-4(2)(10) synthons between donors in nearby dimers. 3 and 4 are semiconductors, and their magnetic susceptibility exhibits a behaviour typical of antiferromagnetically coupled spin chains with magnetic exchange values J/k = -149.9 and -60.1 K, respectively, and in the case of 3, a Curie-Weiss contribution from the paramagnetic anions [Ni(mnt)(2)](-).