Synthesis and characterization of the cyanobenzene-ethylenedithio-TTF donor

Binucleating Jäger-type {(N2O2)2}4- ligands: magnetic and electronic interactions of Fe(II), Ni(II) and Cu(II) across an in-plane TTF-bridge

The simultaneous presence of different electrophores provides an interesting playground for responsive materials. Herein, we present the incorporation of a twice-reversibly oxidizable tetrathiafulvalene (TTF) unit into a binucleating ligand, bridging two metal centers in a fully conjugated plane. A two-step synthesis scheme gave the D2h symmetric Schiff base-like ligand H4L in moderate yields from which the corresponding copper(II) [Cu2L], nickel(II) [Ni2L], [Ni2L(py)4] and iron(II) complexes [Fe2L(py)4], [Fe2L(dmap)4] and [Fe2L(bpee)2]·1 Tol could be obtained. Characterization was performed through 1H-NMR, IR, UV-vis and 57Fe-Mössbauer spectroscopy, SQUID magnetometry and cyclic voltammetry, supported by density functional theory (DFT) calculations. Single crystal X-ray analysis of [Ni2L(py)4] revealed six-coordinate paramagnetic centers, whereas [Ni2L] underwent gradual coordination induced spin state switching (CISSS) in solution. The magnetic independence of both metal centers is echoed by close-to-ideal Curie-plots of the [Cu2L] system and the gradual spin crossover of all iron(II) compounds. By contrast, cyclic voltammetry measurements in solution indicated oxidation-dependent TTF-metal interactions, as well as metal-metal interactions. The reversible TTF-borne events in H4L and [Ni2L] are overlaid with metal-borne events in the case of [Fe2L(py)4], as is corroborated by an analysis of the frontier orbital landscapes and through diagnostic spectral features upon chemical oxidation.

Bilayer conducting salts with polymeric anions

Five new salts of 5-cyanobenzene-ethylenedithio-tetrathiafulvalene (CNB-EDT-TTF), with general formula (CNB-EDT-TTF)4A, and anions A= Ag(CN)2 (1), Ag(CN)2•H2O (2), Ag2(CN)3 (3), Ag(SCN)2 (4) and Hg2(SCN)5 (5), were prepared by electrocrystallisation and characterised...

C–H⋯NC hydrogen bonding in cyanobenzene-ethylenedithio-tetrathiafulvalene compounds

The importance of C–H⋯NC interactions, which although generally considered weak, are effective in the self-assembly of crystal structures.

Structural diversity in conducting bilayer salts (CNB-EDT-TTF)4A

The family of recently described salts based on the electron donor CNB-EDT-TTF and different anions A, with general formula (CNB-EDT-TTF)₄A, constitutes an unprecedented type of molecular conductor based on a bilayer structure of the donors.

A 4-cyanobenzene-ethylenedithio-TTF electron donor and its (1 : 1) triiodide radical cation salt; isomer effects in C–N⋯H–C interactions

A new isomer of the dissymmetric TTF derivative, 4-cyanobenzene-ethylenedithio-tetrathiafulvalene (4-CNB-EDT-TTF) (1), was prepared and compared with the previously reported 5-CNB-EDT-TTF.

Structural relations in (1 : 1) and (2 : 1) cyanobenzene-ethylenedithio-TTF radical salts; the role of CN⋯H interactions

Radical cation salts of 4-CNB-EDT-TTF presenting CN⋯H pairing interactions, semiconducting properties and chains of antiferromagnetically coupled donor dimers.

Polymorphism and Superconductivity in Bilayer Molecular Metals (CNB-EDT-TTF)4I3

Electrocrystallization from solutions of the dissymmetrical ET derivative cyanobenzene-ethylenedithio-tetrathiafulvalene (CNB-EDT-TTF) in the presence of triiodide I₃^- affords two different polymorphs (β″ and κ) with the composition (CNB-EDT-TTF)₄I₃, both with a bilayer structure of the donors. These polymorphs differ in the packing patterns (β″- and κ-type) of the donor molecules in each layer, in both cases with bifurcated C-N···H interactions effectively coupling head-to-head donor molecules between layer pairs. Two β″ polymorphs can be obtained with different degrees of anionic ordering. In one disordered phase, β″_d, with a smaller unit cell, the triiodide anions are disordered over two possible positions in a channel between the donor bilayers, while in the ordered phase, β″_o, the triiodide anions occupy only one of those positions in this channel, leading to the doubling of the unit cell in the layer plane. These results for β″ phases contrast with the κ polymorph previously reported, for which weaker disorder of the triiodide anions, over two possible orientations with 94 and 6% occupation factors, was observed. While the β″ polymorphs remains metallic down to 1.5 K with a ρ_300K/ρ_4K resistivity ratio of 250, the κ polymorph presents a much smaller resistivity ratio in the range of 4-10 and superconductivity with an onset temperature of 3.5 K.

ZnO-nanorods as economical catalyst for synthesis of 4-amino-2-iminodithiole derivatives using tetramethyl thiourea in water

4-amino-2-iminodithiole derivatives were synthesised via multi-component reactions of tetramethyl thiourea, isothiocyanates and alkyl bromides in the presence of ZnO nanorods (ZnO-NR) as the catalyst in water at ambient temperature. These reactions provide low yields without catalysts. The catalyst exhibited significant reusable activity.

Bilayer Molecular Metals Based on Dissymmetrical Electron Donors

The electrocrystallization from solutions of cyanobenzene-ethylenedithio-tetrathiafulvalene (CNB-EDT-TTF) in the presence of different anions X = ClO4(-), PF6(-), and I3(-), affords a new type of 2D molecular metals with composition (CNB-EDT-TTF)4X based on an unprecedented bilayer structure of the donors induced by effective head to head interdonor interactions through the nitrile groups, which is responsible for 2D metallic systems with unusual properties such as the higher band filling, larger effective mass of carriers, and almost degenerated double Fermi surfaces.