Trifluoromethylsulfonyl-based salts of BEDT-TTF: Crystal and electronic structures and physical properties

• Published in: Journal of solid state chemistry 2002-11, Vol.168 (2), p.524-534
• Main Authors: SCHLUETER, John A, GEISER, Urs, GARD, Gary L, MONTGOMERY, Lawrence K, KOO, H.-J, WHANGBO, M.-H, HAU WANG, H, KINI, Aravinda M, WARD, Brian H, PARAKKA, James P, DAUGHERTY, Roxanne G, KELLY, Margaret E, NIXON, Paul G, WINTER, Rolf W
• Format: Article
• Language: English
• Subjects: ANIONS; BEDT-TTF; CHARGE DENSITY; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Conductivity phenomena in semiconductors and insulators; ELECTRIC CONDUCTIVITY; Electron density of states and band structure of crystalline solids; ELECTRON SPIN RESONANCE; Electron states; ELECTRONIC STRUCTURE; Electronic transport in condensed matter; Exact sciences and technology; GEOMETRY; Heterocyclic compounds; Low-field transport and mobility; piezoresistance; MATERIALS SCIENCE; Organic compounds; PHYSICAL PROPERTIES; Physics; Polymers and organic compounds; SPECTROSCOPY; SPIN; Structure of solids and liquids; crystallography; Structure of specific crystalline solids; X-RAY DIFFRACTION
• ISSN: 0022-4596; 1095-726X
• DOI: 10.1006/jssc.2002.9750

Three 2 : 1 salts of the organic donor molecule bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) with trifluoromethylsulfonyl-based anions N(SO{sub 2}CF{sub 3}){sub 2}{sup -}, CH(SO{sub 2}CF{sub 3}){sub 2}{sup -} and C(SO{sub 2}CF{sub 3}){sub 3}{sup -} were prepared by electrocrystallization. These salts were characterized by single-crystal X-ray diffraction, electron spin resonance (ESR) spectroscopy, electrical resistivity measurements and electronic band structure calculations. (ET){sub 2}N(SO{sub 2}CF{sub 3}){sub 2} is a two-dimensional (2D) metal, but its ESR spin susceptibility above 150 K shows a weakly semiconducting behavior, presumably because during ESR measurements the sample cooling rate is slow hence allowing the disordered anions to readjust their positions. (ET){sub 2}N(SO{sub 2}CF{sub 3}){sub 2} is a 2D metal and undergoes a metal-to-insulator (MI) transition at 110 K due probably to a geometry change of the donor molecule layers. (ET){sub 2}N(SO{sub 2}CF{sub 3}){sub 3} is a one-dimensional (1D) metal and undergoes an MI between 180 and 240 K, which is expected to be of charge density wave type.