Mono- and Mixed-Valence Tetrathiafulvalene Semiconductors (TTF)BiI4 and (TTF)4BiI6 with 1D and 0D Bismuth-Iodide Networks

Two new compounds containing tetrathiafulvalene (TTF) cations with extended and discrete anions based on Bi and I are reported. The compound (TTF)­BiI4 comprises [BiI2I4/2]− chains of edge-shared octahedra that are interspersed with stacks of TTF+•. The compound (TTF)4BiI6 has mixed-valence stacks of TTF and TTF+• and discrete molecules of TTF+• separated by discrete [BiI6]−3 anions. The optical and electrical transport properties of these compounds are reported. Due to the mixed-valence stacks of TTF, (TTF)4BiI6 is the significantly better electrical conductor than (TTF)­BiI4, despite the discrete nature of the inorganic moiety.