Search results for "Tetrathiafulvalene"
showing 10 items of 159 documents
Synthesis and radical coupling of pyridine-bridged π-extended tetrathiafulvalene (TTF)-type donors and push–pull analogues
2007
A new family of pi-extended TTF analogues (3a-c) and D-pi-A chromophores (5a-c), in which the electroactive units (1,3-dithiole rings and 2,2-dicyanovinyl groups) are connected through a pyridine bridge with a meta substitution pattern, is reported. The redox behavior of these compounds has been investigated by cyclic voltammetry and theoretical calculations performed at the B3P86/6-31G** level. Unlike many pi-extended TTF derivatives, the 1,3-dithiole rings in compounds 3a-c do not behave independently and two oxidation processes are observed with an anodic separation ranging from 50 to 150 mV. Calculations show that electrons are equally extracted from both dithiole rings. A biradical str…
Tetramethyl-Bis(ethylenedithio)-Tetrathiafulvalene (TM-BEDT-TTF) Revisited: Crystal Structures, Chiroptical Properties, Theoretical Calculations, and…
2013
The (S,S,S,S) and (R,R,R,R) enantiomers of tetramethyl-bis(ethylenedithio)-tetrathiafulvalene (TM-BEDT-TTF) show equatorial conformation for the four methyl groups in the solid state, according to the single-crystal X-ray analyses. Theoretical calculations at the Density Functional Theory (DFT) and time-dependent (TD) DFT levels indicate higher gas phase stability for the axial conformer than the equatorial one by 1.25kcal center dot mole-1 and allow the assignment of the UV-vis and circular dichroism transitions. A complete series of radical cation salts of 1:1 stoichiometry with the triiodide anion I3- was obtained by electrocrystallization of both enantiopure and racemic forms of the don…
Computational modeling of single-versus double-anchoring modes in di-branched organic sensitizers on TiO2 surfaces: structural and electronic propert…
2014
We present a first-principles DFT investigation of the adsorption geometry on the anatase (101) surface of a prototypical di-branched organic dye based on the extended tetrathiafulvalene moiety, incorporating two anchoring cyanoacrylic acid units. Reduced model systems with one and two anchoring groups have been initially studied to investigate the vibrational frequencies related to TiO2 dye adsorption. Our calculations confirm that the reduced systems can be used as reliable models to study the anchoring modes and that the conclusions extracted from the reduced systems can be extrapolated to the entire molecule. A series of molecular structures have been investigated to simulate the anchor…
π conjugation across the tetrathiafulvalene core: Synthesis of extended tetrathiafulvalene derivatives and theoretical analysis of their unusual elec…
2000
A series of extended tetrathiafulvalene (TTF) derivatives bearing one or two 1,4-dithiafulven-6-yl substitutents has been prepared. The new compounds present remarkable electrochemical singularities compared with other TTF derivatives, which are strongly affected by the nature of the substitution on the lateral heterocycle(s). This unusual electrochemical behaviour follows a square-scheme sequence and is attributed to structural changes upon oxidation of the pi-donating molecules. Digital simulations of the electrochemical data have been used to reach the values of the kinetic and thermodynamic constants involved in the square scheme. Theoretical calculations establish an important contribu…
Electronic spectra of tetrathiafulvalene and its radical cation: analysis of the performance of the time-dependent DFT approach
2002
Abstract The electronic spectra of tetrathiafulvalene and its radical cation have been studied within the framework of the time-dependent density functional theory by using a conventional hybrid functional. The behaviour of the method has been analyzed through the computed vertical excitation energies for the low-lying electronic excited states. Although the procedure provides a correct description of many of the features of the spectra, deviations in the range 0.4–0.7 eV have been obtained for several transitions, from which one can conclude misleading assignments.
Thermodynamic and electrochemical study of tailor-made crown ethers for redox-switchable (pseudo)rotaxanes
2020
Crown ethers are common building blocks in supramolecular chemistry and are frequently applied as cation sensors or as subunits in synthetic molecular machines. Developing switchable and specifically designed crown ethers enables the implementation of function into molecular assemblies. Seven tailor-made redox-active crown ethers incorporating tetrathiafulvalene (TTF) or naphthalene diimide (NDI) as redox-switchable building blocks are described with regard to their potential to form redox-switchable rotaxanes. A combination of isothermal titration calorimetry and voltammetric techniques reveals correlations between the binding energies and redox-switching properties of the corresponding ps…
A highly stable and hierarchical tetrathiafulvalene-based metal organic framework with improved performance as a solid catalyst
2018
[EN] Herein we report the synthesis of a tetrathiafulvalene (TTF)-based MOF, namely MUV-2, which shows a non-interpenetrated hierarchical crystal structure with mesoporous one-dimensional channels of ca. 3 nm and orthogonal microporous channels of ca. 1 nm. This highly stable MOF (aqueous solution with pH values ranging from 2 to 11 and different organic solvents), which possesses the well-known [Fe3(¿3-O)(COO)6] secondary building unit, has proven to be an efficient catalyst for the aerobic oxidation of dibenzothiophenes.
Charge transfer salts of tetrathiafulvalene derivatives with magnetic iron(III) oxalate complexes: [TTF]7[Fe(ox)3]2·4H2O, [TTF]5[Fe2(ox)5]·2PhMe·2H2O…
2000
Three novel TTF (tetrathiafulvalene) and TMTTF (tetramethyltetrathiafulvalene) radical salts of monomeric and dimeric iron(III) oxalate magnetic complexes, [TTF]7[Fe(ox)3]2·4H2O 1, [TTF]5[Fe2(ox)5]·2PhMe·2H2O 2 and [TMTTF]4[Fe2(ox)5]·PhCN·4H2O 3, have been synthesized, and their structures and physical properties investigated. The structures for these semiconducting salts feature monodimensional stackings of the radical cations interleaved by the complexes [Fe(ox)3]3− and [Fe2(ox)5]4−, and solvent molecules. For the novel dinuclear complex [Fe2(ox)5]4− antiferromagnetic exchange between the two iron atoms through the oxalate bridge was found.
CCDC 820755: Experimental Crystal Structure Determination
2011
Related Article: F.Riobe, F.Piron, C.Rethore, A.M.Madalan, C.J.Gomez-Garcia, J.Lacour, J.D.Wallis, N.Avarvari|2011|New J.Chem.|35|2279|doi:10.1039/c1nj20310j
CCDC 926041: Experimental Crystal Structure Determination
2013
Related Article: Flavia Pop, Steeve Laroussi, Thomas Cauchy, Carlos J. Gomez-Garcia, John D. Wallis,Narcis Avarvari|2013|Chirality|25|466|doi:10.1002/chir.22210