Bis Ethylenedithio Tetrathiafulvalene Research Articles

Reviving BVDT-TTF and EVT-TTF salts

One foot out of the grave. Forgotten BVDT-TTF and EVT-TTF organic donors are reintroduced and their conducting salts’ physical properties studied through a wide array of techniques.

Adjusting the cation and anion nature in ionic liquids used for the growth control of nanoparticles of organic conductors

Ionic liquids are used for controlling the growth of organic conductors as nanoparticles. We review the conditions of preparation of nanoparticles of conductors derived from tetrathiafulvalene (TTF), tetramethyltetraselenafulvalene (TMTSF) and bis-ethylenedithiotetrathiafulvalene (BEDT-TTF). They are prepared by electrocrystallization using an ionic liquid supporting electrolyte in which the cation plays the role of growth controller and the anion enters the composition of the expected organic conductor. Stable suspensions of nanoparticles are obtained in one case, a valuable characteristic for potential applications in electronic devices.

Metallic Bi‐ and Monolayered Radical Cation Salts Based on Bis(ethylenedithio)­tetrathiafulvalene (BEDT‐TTF) with the Tris(oxalato)gallate Anion

AbstractNew metallic triclinic (1) and monoclinic (2) crystals of the (BEDT‐TTF)4AI[MIII(C2O4)3]G family of organic molecular conductors have been prepared: α‐“pseudo‐κ”‐(BEDT‐TTF)4Kx(H3O)1–x[GaIII(C2O4)3]·1,2‐C6H4Br2 (x ≈ 0.45) (1) and β″‐(BEDT‐TTF)4Kx(H3O)1–x[GaIII(C2O4)3]·PhBr (x ≈ 0.33) (2). The triclinic crystals belong to a quite rare type of bilayered radical ion salts and contain alternating BEDT‐TTF layers with two distinct packing motifs (α‐ and “pseudo‐κ”). The monoclinic crystals contain one kind of BEDT‐TTF radical cation layers. The crystal structure, transport, and magnetotransport properties of 1 and 2 have been studied. The Shubnikov–de Haas (SdH) oscillations were found in both phases. The structure and properties of 1 and 2 are compared with another similar phase with M = FeIII.

Radical salts of TTF derivatives with the metal–metal bonded [Re 2Cl 8] 2− anion

Four new salts of the radical cations of TMTSF (tetramethyltetraselenafulvalene), TMTTF (tetramethyltetrathiafulvalene), BEDT-TTF (bisethylenedithiotetrathia-fulvalene) (ET) and o-Me 2TTF ( o-4,4′-dimethyltetrathiafulvalene) with the metal–metal bonded dianion [Re 2Cl 8] 2− were synthesized, and their structures and physical properties investigated. The structures of these semiconducting salts feature one-dimensional stacking of the donor molecules interleaved with [Re 2Cl 8] 2− anions and interstitial solvent molecules.

Raman Spectroscopy of Polymer Composites with Thin Layers of Bedt-Ttf Trihalide Salts

Conducting polycrystalline layers in polymer composites have been prepared by a two step reticulate doping technique i.e. by exposing solid solution of bis-(ethylenedithiotetrathia) fulvalene (BEDT-TTF) in the polymer matrix to vapours of solvent containing I 2 or IBr. Characterisation of trihalide anion mixtures in the obtained layers of BEDT-TTF salts was completed by low frequency Raman spectroscopy. The surface morphology and the chemical composition of the layers were investigated by means of scanning electron microscopy with energy dispersive X-ray microanalysis and atomic force microscopy.

Temperature dependence of structure and phonons of α- and β-TTF crystals

Raman phonon spectra of tetrathiafulvalene (TTF) crystals in their monoclinic (α-TTF) and triclinic (β-TTF) polymorphic modifications have been recorded as a function of temperature in the 30 to 130 cm−1 range. Along with other model potentials, the set of parameters already adopted for the study of ionic and neutral forms of bis-ethylen-dithio-tetrathiafulvalene (BEDT-TTF) has been used to compute, within a quasi-harmonic lattice dynamics framework, the crystallographic structures and the phonon frequencies of the two polymorphs as a function of temperature with good results. Introduction of the internal vibrational degrees of freedom of the TTF molecules in the crystals improves the computational approach and proves to be a valuable tool to judge the importance of the coupling between lattice phonons and intramolecular vibrations.

Neutral bis(ethylenedithio)tetrathiafulvalene at 100 K

The low-temperature crystal structure of bis­(ethyl­enedi­thio)­tetra­thia­fulvalene (BEDT-TTF), C10H8S8, is similar to its high-temperature structure. The room-temperature central bond lengths of this mol­ecule are often used as reference in empirical methods to estimate the charge carried by the (BEDT-TTF)xn+ cations in the BEDT-TTF mol­ecule-based organic conductors. We show that the method we previously reported can still be used with low-temperature BEDT-TTF salts data. Moreover, we confirm the purely thermal origin of the ordering of the ethyl­ene group.

Neutral bis(ethylenedithio)tetrathiafulvalene at 100 K

The low-temperature crystal structure of bis­(ethyl­enedi­thio)­tetra­thia­fulvalene (BEDT-TTF), C10H8S8, is similar to its high-temperature structure. The room-temperature central bond lengths of this mol­ecule are often used as reference in empirical methods to estimate the charge carried by the (BEDT-TTF)xn+ cations in the BEDT-TTF mol­ecule-based organic conductors. We show that the method we previously reported can still be used with low-temperature BEDT-TTF salts data. Moreover, we confirm the purely thermal origin of the ordering of the ethyl­ene group.

Crystallography in four and five dimensions as applied to multi-sublattice (composite) structures

Composite structures, containing two or more sublattices in one crystal, are of importance in the search for new materials. They are classified in terms of the interlattice matrix relating the sublattices, and by the use of chemical criteria The use of superspace to interpret the diffraction pattern and perform calculations on electronic structure and lattice energy is referred to. The composite low-dimensional conductors (BEDT-TTF)Hg 0.776 (SCN) 2 and (BEDT-TTF) 4 Hg 2.88 Br 8 (BEDT-TTF = bisethylene dithiotetrathiafulvalene) are discussed as examples. Of particular interest are the interaction between the sublattices and the change of structure and properties as a function of temperature.

A facile synthesis of bis(ethylenedithio)tetrathiafulvalene and related donors for synthetic metals

Summary form only given. Bis(ethylene)dithiotetrathiafulvalene (BEDT-TTF), bis(oxybis(methylenethio))tetrathiafulvalene (BOBMT-TTF) and bis-(thiobis(methylenethio))tetrathiafulvalene (BTBMT-TTF) and related donors were prepared in two steps starting from 1,3,4,6-tetrathiapentalene-2,5-dione (thiapendione) via the intermediate 4,5-dimercapto-1,3-dithiol-2-one. The reaction conditions for and the mechanism of the basic cleavage of thiapendione are briefly discussed.

Coexistence of Mobile and Localized Electrons in Bis(ethylene)dithiotetrathiafulvalene (BEDT‐TTF) Radical Salts with Paramagnetic Polyoxometalates: Synthesis and Physical Properties of (BEDT‐TTF)8[CoW12O40]· 5.5 H2O

Alternating layers of radicals of the π-electron donor 1 and of polyoxonions [CoW12O40]6− (2, polyhedral representation) are contained in the title compound. Thus, organic charge carriers and inorganic electron-acceptor components lie next to each other. Since the polyoxometalates can accommodate different metal ions at specific sites, such anions are attractive precursors for the preparation of radical cation salts with new electrical and magnetic properties.

Structure—reactivity relationship in Langmuir—Blodgett films of bisethylenedithio-tetrathiafulvalene (BEDT-TTF) derivatives

BEDT-TTF (bisethylenediothio-tetrathiafulvalene) derivatives, labeled 1a and 1b, are used to build Langmuir—Blodgett films. In the first step, oxidation by iodine vapor leads in both cases to the formation of radical cation dimers: ( 1a ·+) 2 and ( b ·+) 2. However, the subsequent behavior of films strongly depends on the way the aliphatic substituents are grafted onto the electroactive nucleus. Built up films of 1b go back reversibly to their initial insulating state and those of 1a undergo a solid state reorganization leading to a permanent conducting phase. These differences are explained in terms of steric hindrance. Spectroscopical arguments are used to derive the stoichiometry of the conducting films of 1a which is likely to be that of conducting bulk crystals of (BEDT-TTF) 2I 3 −.

New cation-radical salts of BEDT-TTF with the octahedral metal complex anions PtCl 62−, PtBr 62−, TeCl 62− and SnCl 62−. Synthesis, structure and properties

A new series of isostructural cation-radical salts of bis(ethylene)dithiotetrathiafulvalene (BEDT-TTF) with the octahedral metal complex dianions PtCl 6 2−, PtBr 6 2−, TeCl 6 2− and SnCl 6 2− have been obtained. The crystal structure of the (BEDT-TTF) 4PtCl 6C 6H 5CN salt has been determined. Although it should be attributed to the k-type of BEDT-TTF metallic salts due to the packing arrangement of the BEDT-TTF molecules, it undergoes a first-order transition into the insulating state at 250 K. Application of a pressure higher than 6 kbar results in a new conducting state. The complexes of (BEDT-TTF) with the anions PtBr 6 2−, TeCl 6 2− and SnCl 6 2− exhibit semiconducting properties.