A. Hountas

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).

Crystal structures and properties of some cation radi EDOMDTTTF, EDOVDTTTF, EDOBTTF, EDOPDSDTF, EDODMPTTF, BEDTTTF and BMDTTTF

Abstract Some cation radical salts based on ethylenedioxyethylenedithio-tetrathia fulvalene (EDOEDTTTF), ethylenedioxymethylenedithiotetra-thiafulvalene (EDOMDTTTF), ethylenedioxyvinylenedithiotetrathia-fulvalene (EDOVDTTTF), ethylenedioxybenzotetrathiafulvalene (EDOBTTF), ethylenedioxypyrazinodiselenadithiafulvalene (EDOPDSDTF), ethylene-dioxymethylpyrazinotetrathiafulvalene (EDODMPTTF), bis(ethylene-dithio) tetrathiafulvalene (BEDTTTF) and bis(methylenedithio) tetra-thiafulvalene (BMDTTTF) п-donor molecules were studied.

Structural and electrical properties of some cation radical salts based on EDTTTF, PEDTTTF, and similar π-donors

Abstract The X-ray structural and electrical properties of some cation radical salts of the type D n X [where D=ethylenedithiotetrathiafulvalene (EDTTTF), pyrazinoethylenedithiotetrathiafulvalene (PEDTTTF), methylenedithiotetrathiafulvalene (MDTTTF), pyrazinoethylenedithiodiselenadithiafulvalene (PEDTDSDTF), ethylenedithiodiselenadithiafulvalene (EDTDSDTF), [4,5-b] pyridinodithiotetrathiafulvalene ([4,5-b]PEDTTTF), dimethylethylenedithiotetrathiafulvalene (DMEDTTTF), bis(ethylenedithio) tetrathiafulvalene (BEDTTTF); X=I 3 , IBr 2 , AuI 2 , BF 4 , ClO 4 , PF 6 , etc; n=1,2…] were studied.

Conducting and Superconducting Salts Based on Some Symmetrical and Unsymmetrical Donors

Conducting and superconducting salts based on bis(ethylenedithio)tetrathiafulvalene, ehtylenedithioselenatrithiafulvalene, ethylenedioxyethylenedithiotetrathiafulvalene, and ethylenedioxyvinylenedithiotetrathiafulvalene were prepared and studied.

Crystal structures, electrical and optical properties of (BPTTF)mXn, (PEDTTTF)mXn (X=BF4, I3) and similar salts

Abstract The main feature in the crystal structures of the compounds (BPTTF)mXn [where BPTTF=bis (pyrazino) tetrathiafulvalene] and (PEDTTTF)mXn [where PEDTTTF=pyrazino-ethylenedithiotetrathiafulvalene] is the interstack S⋯N and S⋯S contacts, in which the S⋯N and S⋯S distances are shorter than the corresponding van der Waals distances (3.35 and 3.70 A, respectively). The dc conductivity in single crystals is of the order 10−2 and 40Ω−1cm−1, for (BPTTF)mXn and (PEDTTTF)mXn, respectively, at room temperature. The reflectance spectra show bands in the UV-visible spectral region and an upward slope from 1500 and 2500 nm, respectively, to longer wavelengths. Similar results are obtained from (DMPEDTTTF)3-I3 [where DMPEDTTTF=dimethylpyrazinoethylenedithiotetrathiafulvalene]. The compounds α-(PEDTTTF)3I3, β-(PEDTTTF)3I3 and β-(DMPEDTTTF)3I3 exhibit metal-insulator transition below the room temperature.

Synthesis and structure of black (EDTTTF)2IBr2: A structural analogue of β-(BEDTTTF)2X organic superconductors

Abstract Crystals of the black form of (EDTTTF)2IBr2 [where EDTTTF is ethylenedithiotetrathiafulvalene] were prepared by the electro crystallization method. The structure belongs to space group P-1 with Z = 1. It is made up of “corrugated sheet” networks of S…S interstack interactions [ d s…s A ], separated by networks of IBr2 anions with Br…Br interactions [ d Br…Br = 4.013(1) A ]. Both the anions and ethylene groups are ordered. The crystals satisfy the structural criteria of the β-form of (BEDTTTF)-superconductors.