Mono- and Mixed-Valence Tetrathiafulvalene Semiconductors (TTF)BiI4 and (TTF)4BiI6 with 1D and OD 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 [Bi2I4/2]chains of edge-shared octahedra that are interspersed with stacks of TTF+center dot. The compound (TTF)(4)BiI6 has mixed-valence stacks of TTF and TTF+center dot and discrete molecules of TTF+center dot 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)(4)BiI6 is the significantly better electrical conductor than (TTF)BiI4, despite the discrete nature of the inorganic moiety.