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

Abstract

Two new compounds containing tetrathiafulvalene (TTF) cations with extended and discrete anions based on Bi and I are reported. The compound (TTF)BiI₄ comprises [BiI₂I_4/2]^- 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.