Inter-layer charge disproportionation in the dual-layer organic metal (tTTF-I)2ClO4 with unsymmetrical I···O halogen bond interactions.

摘要: A mixed-valence salt of tTTF-I with ClO4−, formulated as (tTTF-I)2ClO4, is characterized by the presence two crystallographically independent donor molecules, segregated in different layers and linked together through I⋯O interactions ClO4− anion disordered at room temperature. The molecule was prepared metallation tTTF (trimethylene tetrathiafulvalene) followed reaction iodine to afford mono diiodo derivatives tTTFI2, respectively. crystal structure latter neutral tTTFI2 shows occurrence strong type II, I⋯I halogen bond interactions. Band calculations dual-layer 2 : 1 (tTTF-I)2ClO4 show co-existence both 1D open 2D closed Fermi surfaces. undergoes a metal–insulator phase transition TMI = 90 K, associated an electronic dimensionality decrease, since already 100 part surface transforms into corrugated planes. High resolution X-ray investigations performed combined multipolar refinements, indicate approximately equivalent +0.5e charge also deduced from intramolecular distances. On other hand, Raman spectroscopic that ambient temperature actually distributed non-uniformly conducting identification molecules charges +1, +0.5, 0e, while low distribution becomes essentially uniform (+0.5e), confirmed high data. These apparently contradictory behaviors are consequence partial electron transfer between slabs reach common level metallic phase.