J. S. Zambounis

Low temperature measurements of the electrical conductivities of some charge transfer salts with the asymmetric donors MDT-TTF, EDT-TTF and EDT-DSDTF. (MDT-TTF)2AuI2, a new superconductor (Tc=3.5 K at ambient pressure)

Abstract The electrical and x-ray structural properties of the new superconductor (MDT-TTF) 2 AuI 2 with a T c of 3.5 K at ambient pressure were studied (MDT-TTF = methylenedithio-tetrathiafulvalene). Low temperature measurements of the electrical conductivities of two new metals, (EDT-TTF) 2 IBr 2 and (EDT-DSDTF) 2 AuI 2 are reported (EDT-TTF = ethylenedithio-tetrathiafulvalene, EDT-DSDTF = ethylenedithio-diselenadithiafulvalene).

A new synthesis of unsymmetrical chalcogene substituted tetrachalcogene-fulvalenes.

Abstract The synthesis of pure, substituted, unsymmetrical tetrachalcogene fulvalenes from trimethyl-silyl-ethoxymethyl (SEM) protected TTF intermediates is described.

Bis (Alkylthio) Tetrathiafulvalenes and a Few of Their Salts

Abstract Some unsymmetrical bis(alkylthio) tetrathiafulvalenes (π-donors) and a number of their charge transfer complexes and cation radical salts of the type DmXn (where D=π-donor, X=TCNQ, I3, IBr2, PF6, CIO4) have been prepared and studied.

Conducting solids based on some new unsymmetrical tetraheterofulvalenes

Abstract Some new unsymmetrical polysulfur- or pyrazino-tetraheterofulvalenes (D) and a number of their charge transfer complexes and cation radical salts of the type D n X [where D=donor, X=TCNQ, Ni(dmit) 2 , Ni(dcit) 2 , I 3 , AuI 2 , IBr 2 , SCN, C10 4 , and PF 6 ] were prepared and studied. Most of the D n X were found to be conducting solids.

Structural and Physical Properties of τ-(EDO-S,S-DMEDT-TTF)2 (AuBr2)1(AuBr2)y

Abstract The crystal structure and physical properties of τ-(EDO-S,S-DMEDT-TTF)2 (AuBr2)1(AuBr2)y (where EDO-S,S-DMEDT-TTF is ethylenedioxy-S,S-dimethylethylenedithiotetrathiafulvalene and y ≃ 0.75) showed that this is a two-dimensional metal.

Bis-(trimethylsilyl-ethoxymethyl)-dichalcogenides and their application to tetrachalcogene-fulvalenes.

Abstract The synthesis of the bis (trimethylsilyl-ethoxymethyl)-disulfide and -diselenide (SEM-X 1 -X 1 -SEM) as well as their reaction with lithiated tetrachalcogene fulvalenes (TXF; X=S, Se) is described.

A new electronic state in the variably doped two-dimensional charge transfer salt, τ-(EDO-S,S-DMEDT-TTF)2 (I3)1 (I3)y and τ-(EDO-S,S-DMEDT-TTF)2 (AuBr2)1 (AuBr2)y with y∼0.75

Abstract Two topics are presented which are remarkable in the organic charge transfer salts. First, in this two-dimensional conductor, we could achieve varying the effective doping concentration so that we could change the nature from semiconducting (dρ/dT 0) by reducing y in the titled formula. This drastic change can be interpreted as an increase in the carrier number by expanding the Fermi surface by reducing y in the I3-salt. Second, a strong negative magnetoresistance state is observed suddenly below ∼60 K. Since the magnetic response changes across this temperature, an electronic phase transition might occur. In this low temperature phase, below about 30 K, the angular dependence of the magnetoresistance becomes hysteretic, implying that this system is related to magnetism.

Some Nitrogen-Containing Tetraheterofulvalenes and a Few of Their Conductive Salts

Abstract Unsymmetrical tetraheterofulvalenes (π-Donors) having at least one pyrazino-ring and a number of their charge transfer complexes and cation radical salts have been prepared and studied.

Structural and physical properties of τ-(P-S, S- DMEDT-TTF)2(AuBr2)1(AuBr2)0.75 and τ-(EDO-S, S-DMEDT-TTF)2(AuBr2)1 (AuBr2)0.75, 2D conductors

Abstract The structural and physical properties of the title compounds (where P- S,S -DMEDT-TTF is pyrazino- S,S -dimethylethylenedithio-tetrahiafulvalene and EDO- S,S -DMEDT-TTF is ethylenedioxy- S,S -dimethylethylenedithio-tetrathiafulvalene) show that these crystals are 2D metals with unusual behaviour for temperatures lower than that of metal-insulator transition (

Conducting and superconducting salts based on BEDTTTF and on some unsymmetrical tetrachalcogenafulvalenes

Abstract The physical properties of conducting and superconducting salts based on bis(ethylenedithio) tetrathiafulvalene and on some unsymmetrical tetrathiafulvalenes (containing ethylenedithio-,ethylenedioxy-,vinylenedithio-,dimethylethylenedithio-, and pyrazino- as additional heterogroups) are reportd. β-, υ-, and τ-phases are found to be the most important.