New cation-anion interaction motifs, electronic band structure, and electrical behavior in. beta. -(ET)/sup 2/X salts (X = ICl/sub 2/. pi. and BrICl/sup -/). [. beta. -bis(ethylenedithio)tetrathiafulvalene]

Journal Article · Wed Feb 19 04:00:00 EST 1986 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00264a020· OSTI ID:5896844

Emge, T J; Wang, H H; Leung, P C.W.; Rust, P R; Cook, J D; Jackson, P L; Carlson, K D; Williams, J M; Whangbo, M H; Venturini, E L; Schirber, J E

Two new organic metals, ..beta..-(ET)/sub 2/ICl/sub 2/ and ..beta..-(ET)/sub 2/BrICl, were synthesized, and their structures and electronic properties were characterized via X-ray diffraction, ESR studies, and band electronic structure calculations. BEDT-TTF, abbreviated ET, is bis(ethylenedithio)tetrathiafulvalene, C/sub 10/S/sub 8/H/sub 8/. The packing of the ET molecules within the sheetlike network of these two isostructural salts is significantly different from that of the two-dimensional metals ..beta..-(ET)/sub 2/X with the larger anions X/sup -/ = I/sub 3//sup -/, I/sub 2/Br/sup -/, IBr/sub 2//sup -/, and AuI/sub 2//sup -/, where all but X/sup -/ = I/sub 2/Br/sup -/ are ambient-pressure superconductors. The ESR studies for the ..beta..-(ET)/sub 2/ICl/sub 2/ salt show that it is metallic down to approx. 22 K, at which temperature a metal-insulator transition is observed. The band electronic structures calculated for ..beta..-(ET)/sub 2/ICl/sub 2/ and ..beta..-(ET)/sub 2/BrICl reveal that these salts are one-dimensional metals. Comparison of the structures and electronic properties of the ..beta..-(ET)/sub 2/X salts with large linear anions (e.g., X/sup -/ = I/sub 3//sup -/, I/sub 2/Br/sup -/, IBr/sub 2//sup -/, and AuI/sub 2//sup -/) vs. those with the small symmetric (Cl-I-Cl)/sup -/ and asymmetric (Br-I-Cl)/sup -/ anions leads us to conclude that the nature of the interactions between ET molecules within a given sheetlike network, and hence the dimensionality of electrical properties, is strongly governed by the packing motif of ET molecules around a particular X/sup -/ anion. 42 references, 5 figures, 6 tables.

• Research Organization: Argonne National Lab., IL
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5896844
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 108:4; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
CHEMICAL PREPARATION
COHERENT SCATTERING
CRYSTAL STRUCTURE
DATA
DIFFRACTION
ELECTRON SPIN RESONANCE
ELECTRONIC STRUCTURE
EXPERIMENTAL DATA
INFORMATION
LATTICE PARAMETERS
LOW TEMPERATURE
MAGNETIC RESONANCE
MEDIUM TEMPERATURE
NUMERICAL DATA
ORGANIC BROMINE COMPOUNDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
ORGANIC SULFUR COMPOUNDS
RESONANCE
SCATTERING
SYNTHESIS
TEMPERATURE DEPENDENCE
VERY LOW TEMPERATURE
X-RAY DIFFRACTION