Tetrathiafulvalene Research Articles

X-ray structural study of charge and anion orderings of TMTTF salts

High resolution X-ray structure analyses and electronic structure calculation revealed the condition for the charge ordering(CO) observed in the (TMTTF) 2 X (Fabre) salts. The phase diagram of the electronic states including 2k F and 4k F CO has been proposed associated with magnitudes of molecular dimerization and tetramerization.

Synthesis and Applications of Tetrathiafulvalenes and Ferrocene‐tetrathiafulvalenes and Related Compounds

AbstractFor Abstract see ChemInform Abstract in Full Text.

Tetrathiafulvalenes acting as leaving groups: a route to bithiazoles.

Tetrathiafulvalenes acting as leaving groups: a route to bithiazoles.

Tetrathiafulvalenes Acting as Leaving Groups: A Route to Bithiazoles

Man findet sie noch immer: neuartige Heterocyclen wie die abgebildete Bithiazol-Ringanordnung (N blau, S gelb). Diese Verbindung aus verbrückten bicyclischen Heterocyclen entsteht bei einer Reaktion, in der ein funktionalisiertes Tetrathiafulvalen als Abgangsgruppe wirkt. Der Mechanismus schließt unter anderem oxidative Cyclisierungen ein.

Mechanism bridging antiferromagnetism and superconductivity to the Mott insulating state in quasi-one dimensional organic conductors

The pressure dependence of the Mott, spin-density-wave and superconducting instabilities of the metallic state of the Bechgaard and Fabre salts is analyzed using weak coupling scaling theory. We show how the mechanism of quantum interference between pairings in the density-wave and superconducting channels, when combined to the influence of intrachain Umklapp scattering and inter-chain hopping under pressure, can play an essential role in the sequence of instabilities for these quasi-one dimensional metals under pressure.

Tetrathiafulvalene and Its Derivatives as π‐Electron Donating Units in Pseudorotaxanes, Rotaxanes, and Catenanes

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of a new polyfluorinated vinylogue of tetrathiafulvalene through 1,3-dipolar cycloaddition of ethyl beta-bromoperfluorodithiocrotonate with dimethyl acetylenedicarboxylate.

The ethyl ester of beta-bromoperfluorodithiocrotonic acid reacts with dimethyl acetylenedicarboxylate to give 1,4-difluoro-2,3-bis(trifluoromethyl)-but-2-ene-1,4-diylidene-2,2'-bis(4',5'-dicarbomethoxy-1',3'-dithiole) (4), a new type of vinylogue of tetrathiafulvalene. The thermal transformations of this compound lead, depending on the temperature, to the formation of the cyclization products: 11,14-difluoro-2,3,8,9-tetra(carbomethoxy)-12,13-bis(trifluoromethyl)-1,4,7,10-tetrathiadispiro[4.0.4.4]tetradeca-2,8,11,13-tetraene (8) or 5,8-difluoro-6,7-bis(trifluoromethyl)-2,3-bis(carboxymethyl)-1,4-benzodithiine (11).

Chemical modification of the superconducting β-(ET)2SF5CH2CF2SO3 structure through use of CF3CRR'SO3-anions

Discrete, organic anions provide an attractive alternative for the synthesis of molecular superconductors. We have previously prepared the first completely organic superconductor, β-(BEDT-TTF) 2 SF 5 CH 2 CF 2 SO 3 [BEDT-TTF, hereafter abbreviated ET is bis(ethylenedithio)tetrathiofulvalene]. Molecular metals which contain organic anions are essentially free of the magnetic impurities (i.e. Cu +2 ) that often plague the physical property studies of organic superconductors such as κ-(ET) 2 Cu[N(CN) 2 ]Br. We have undertaken a research effort aimed at the crystallization of conducting charge transfer salts which possess fluorinated alkylsulfonate anions as the charge compensating entities. Herein we report the extension of this work to include the synthesis and characterization of ET salts of the trifluoromethylsulfonate anions, CF 3 CRR'SO 3 - (R, R' = F, H).

X-ray observation of 2kF and 4kF charge orderings in (TMTTF)2Re04 and (TMTTF)2SCN associated with anion orderings

Electronic transfer integrals (t) and TMTTF molecular ionicities (p) in several Fabre salts were estimated using the atomic coordinates obtained by systematic X-ray structure analyses at room and low temperatures. Among these Fabre salts containing the octahedal anions, (TMTTF)2PF6 has the largest degree of 4kF bond dimerization in t, (TMTTF)2AsF6, does the middle and (TMTTF)2SbF6 has the smallest. This tendency correspondr well to the degree of 2kF spin-Peierls instability at low temperatures which had been estimated. However opposite tendency was observed between the magnitude of the 4kF, bond dimerization and the reported critical temperature of the charge disproportionation. The charge mochlation patterns and the transfer integral modulation patterns of two salts containing non centrosymmetric anions, (TMTTF)2ReO4 and (TMlTF)2SCN were compared.

The Design and Synthesis of Versatile Molecular Building Blocks: Working Towards the Controlled Self-Assembly of Novel Functional Materials

Our research goals are focused on the preparation of novel molecule-based materials that possess specifically designed properties in solution or in the solid state e.g. self-assembly, magnetism, conductivity and spin crossover phenomena. Most of our systems incorporate paramagnetic transition metal ions and the search for new molecule-based magnetic materials is a prominent theme. Specific areas of research include the preparation and study of oxalate based 2D and 3D magnets, probing the versatility of octacyanometalate building blocks as precursors for new molecular magnets, and the preparation of new tetrathiafulvalene (TIF) derivatives for applications in molecular and supramolecular chemistry.

Structural properties of strongly correlated quasi-1D organic systems

Correlated quasi-1D electron gas exhibit 2kF and 4kF CDW/BOW instabilities widely observed among the organic conductors. The Bechgaard and Fabre salts exhibit mixed SDW-CDW, Anti-ferromagnetism (AF) and spin peierls (SP) ground states achieving a subtle coupling between the spin and lattice degrees of freedom. The SP and AF nature of the Fabre salts’ ground state is analyzed in relation with the presence of a high temperature 4kF CDW-ferroelectric phase transition.

The case for universality of the phase diagram of the Fabre and Bechgaard salts

We report the observation of superconductivity in the spin-Peierls Fabre salt (TMTTF)2PF6 from pressure dependent electrical transport measurements above a threshold of 4.35 GPa. The data complete the sequence of ground states of this compound in the temperature and pressure plane adducing an empirical basis to the universal character of the phase diagram of the Fabre salts and their selenide analogues, the Bechgaard salts. The structure of the phase diagram at the approach of the crossover between spin-density wave and superconducting states is compared with the results of scaling theory of the interplay between both electronic instabilities under pressure. The comparison supports the view that magnetism and superconductivity in these compounds have a common electronic origin.

Structural features of the Bechgaard salts and related compounds

We present an overview of the structural instabilities and of the structural transitions exhibited by the Bechgaard salts (TMTSF)2X, the Fabre salts (TMTTF)2X, and related compounds. In the (TMTTF)2X and (BCPTTF)zX series with centrosymmetric anions X, such as PF6, a 2k~ bond instability leads to the formation of a spin-Peierls (SP) ground state. A quantitative analysis of its one dimensional (ID) pretransitional fluctuations, previously performed in the BCPTTF series, is extended to the inorganic SP compound CuGeOs. In the (TMTSF)2X series, the 1D 2k~ charge density wave (CDW) structural fluctuations vanish at low temperature when the spin density wave correlations develop. However the detection of very weak 2k~ and 4k~ satellite reflections shows that the density wave ground state of (TMTSF)2PF6 unexpectedly presents a mixed spin-charge character. In salts with X non-centrosymmetric, the anions, disordered at room temperature, order in a superlattice upon cooling. However, because of their coupling with the organic sublattice, these ordering lead to important modifications of the electronic properties. Finally, we report a quantitative analysis of the 1D 2k~ and 4k~ CDW lattice fluctuations observed in the TTF-TCNQ family, allowing to extract the exponent K, governing the collective instabilities of the Luttinger liquid.

Lead-Selective Membrane Potentiometric Sensor Based On A Recently Synthesized Dimethyl Benzo Tetrathia Fulvalene

ABSTRACT A PVC membrane electrode for lead ion based on dimethyl benzo tetrathia fulvalene(DMBTTF)as membrane carrier was developed. The electrode exhibits a Nernstian response for Pb2− over a wide concentration range (10−2−10−5 M) with a limit of detection of 8*10−6M. It has a response time of 20s and can be used for at least 2 months without any considerable divergence in potentials. The proposed membrane sensor revealed good selectivities for Pb2− over a wide variety of other metal ions and could be used in pH range of 3.0-6.0.

Novel One-Dimensional Organic Conductor Based on Selenium-Containing Bis-Fused Tetrathiafulvalene Derivative, (TSM-TTP)(I3)5/3

Abstract A novel selenium-containing bis-fused tetrathiafulvalene donor, TSM-TTP (2,5-bis[4,5-bis(methylseleno)-1,3-dithiol-2-ylidene]-1,3,4,6-tetrathiapentalene) forms a 3 : 5 triiodide salt, (TSM-TTP)(I3)5/3. This salt has uniform one-dimensional columns of the donors, and is isostructural to the corresponding complex of the sulfur analog. This compound shows a high electrical conductivity, 200 S cm−1 at room temperature, and undergoes a metal-insulator transition around 20 K. Another insulating (σrt = 0.03 S cm−1) phase with trimerized columns is also obtained.

Temperature dependence of the electronic structure of α-(BEDT-TTF) 2MHg(SCN) 4 (M = NH 4, K, Rb)

By using the reported temperature dependence of the lattice constants for organic metals α-(BEDT-TTF) 2MHg(SCN) 4 (M = NH 4, K, Rb), where BEDT-TTF is bis(ethylenedithio)tetrathia fulvalene, the temperature dependence of the transfer integrals have been calculated. In addition the derivatives of each transfer integral with respect to each lattice constant are calculated. The transfer integrals are sensitive to the change of the lattice constants within the conducting sheet. The gap between the open and closed orbits in the momentum space is principally generated by the difference of the transfer integrals, c1 and c2; the magnitude of the intrastack dimerization the separation between the open and closed orbits. Among the various salts, the NH 4 salt shows an exceptionally large shrinkage of the lattice constant c, which gives rise to large c1 – c2, a large gap, and results in a comparatively small cross section of the closed Fermi surface.

4,4′(5′)-Disubstituted tetrathiafulvalenes and systems with extended conjugation incorporating TTF spacers

Abstract Difunctionalised tetrathiafulvalenes 2–6 have been prepared from 4,4′(5′)-bis(methoxycarbonyl)tetrathiafulvalene ( 1 ).

Tetrathiafulvalene .pi.-Stacks in Water

Tetrathiafulvalene .pi.-Stacks in Water

ChemInform Abstract: A New Route to 1,3‐Dithioles from Mesoionic 2‐Piperidino‐5‐aryl‐1,3‐ dithiolium‐4‐thiolates. Synthesis of 2‐(1,3‐Dithiolan‐2‐ylidene)‐1,3‐ dithioles and Tetrathiafulvalenes Using These New Dithioles.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Synthesis of some bis(aryl) substituted TTF:S.

The synthesis of three new bis(aryl)substituted tetrathiafulvalenes is presented together with their cyclovoltammetric behaviour.