Comparison of the Crystal and Electronic Structures of Three 2:1 Salts of the Organic Donor Molecule BEDT-TTF with Pentafluorothiomethylsulfonate Anions SF5CH2SO3 -, SF5CHFSO3 -, and SF5CF2SO3

• Published in: Chemistry of materials Vol. 12; no. 2; pp. 343 - 351
• Main Authors: Ward, Brian H, Schlueter, John A, Geiser, Urs, Wang, H. Hau, Morales, Emilio, Parakka, James P, Thomas, Seddon Y, Williams, Jack M, Nixon, Paul G, Winter, R. W, Gard, Gary L, Koo, H.-J, Whangbo, M.-H
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 21-02-2000
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Conductivity of specific materials; Electron density of states and band structure of crystalline solids; Electron states; Electronic transport in condensed matter; Exact sciences and technology; Heterocyclic compounds; Organic compounds; Physics; Polymers and organic compounds; Polymers; organic compounds (including organic semiconductors); Structure of solids and liquids; crystallography; Structure of specific crystalline solids; Temperature dependence; Raman spectra; Band structure; Electrical conductivity; Molecular structure; Electrocrystallization; Sulfonates; XRD; Experimental study; Magnetic susceptibility; Organic anion; Sulfur heterocycle; Electronic structure; Hydrogen bonds; BEDT-TTF; Chemical preparation; Bicyclic compound; Charge transfer complexes; EPR spectra; Organic radical cation; Crystal structure
• ISSN: 0897-4756; 1520-5002
• DOI: 10.1021/cm990238q

Salts of the donor molecule, bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET), with pentafluorothiomethylsulfonate (SF5CX2SO3 -, X = H or F) anions have been prepared. Three phases, β‘ ‘-(ET)2SF5CH2SO3, β‘-(ET)2SF5CF2SO3, and β‘ ‘-(ET)2SF5CHFSO3 were obtained by electrocrystallization with the corresponding LiSF5CX2SO3 electrolytes. The structures of these salts were determined by single-crystal X-ray diffraction, and their physical properties were examined by electrical resistivity measurements as well as by ESR and Raman spectroscopy. The β‘ ‘-(ET)2SF5CH2SO3, β‘ ‘-(ET)2SF5CHFSO3 and β‘-(ET)2SF5CF2SO3 salts are considerably different in their crystal structures, physical properties, and electronic structures despite the similarity in the structures of the SF5CX2SO3 - (X = H, F) anions. The β‘ ‘-(ET)2SF5CH2SO3 salt has two kinds of ET donor molecules with considerably different charge densities. The electronic structure of β‘ ‘-(ET)2SF5CHFSO3 has both one-dimensional (1D) and two-dimensional (2D) Fermi surfaces which are similar to those found in the organic superconductor β‘ ‘-(ET)2SF5CH2CF2SO3. The ESR data for the β‘-(ET)2SF5CF2SO3 salt indicate that it opens a spin gap below 45 K. The differences in the physical properties of the three salts were analyzed by calculating the HOMO−HOMO interaction energies between nearest-neighbor ET molecules in their donor molecule layers.