We present the results of measuring the dynamic magnetic susceptibility and surface impedance of a unique layered organic superconductor κ-(BEDT-TTF) 4 Hg 2.89 Br 8 (κ-HgBr). In this material, strong electronic correlations coexist with weak doping associated with lattice incommensurability. The superconducting properties of this material are studied by several methods: the temperature dependences of the resistance across the conducting layers, the dynamic magnetic susceptibility, and the surface impedance in the conducting planes are measured. The results of measuring the resistance and dynamic magnetic susceptibility at a frequency of 100 kHz demonstrated the presence of a superconducting state at temperatures below T c = 3.1 K. The results of measuring the temperature dependence of the surface impedance Z ( T ) = R ( T ) + iX ( T ) of several samples at a frequency of 28 GHz in the temperature range from 0.5 K to 50 K turned out to be unusual. In the studied samples at T < 3 K, a sharp change in Z ( T ) is not observed, and some samples even demonstrate weak “dielectricization” at low temperatures.

The energy spectrum of C 82 fullerene (isomer no. 3 of C 2 symmetry) is calculated within the Hubbard model in the approximation of static fluctuations. Based on the energy spectrum, optical absorption spectra of this isomer in neutral and anionic states with one, two, three, and four additional electrons are simulated. The calculated optical spectra in neutral and monoanionic states are compared with known experimental spectra.

В рамках модели Хаббарда в приближении статических флуктуаций вычислен энергетический спектр фуллерена C82 (изомер N 3 симметрии C2). На основе энергетического спектра смоделированы спектры оптического поглощения данного изомера в нейтральном и анионных состояниях c одним, двумя, тремя и четырьмя дополнительными электронами. Проведено сравнение расчетных оптических спектров в нейтральном и моноанионном состояниях с известными экспериментальными спектрами. Работа выполнена при финансовой поддержке РФФИ (проекты N 14-08-00824-a, 16-03-00810-a) и гранта МарГУ N 2014-003a. DOI: 10.21883/FTT.2017.01.43974.194

The Diels-Alder reaction of C-1-C-70(CF3)(10) and butadiene sulfone yielded 82 mol% from starting material of single C-70(CF3)(10)C4H6 regioisomer. The optimization of the synthesis conditions C-70(CF3)(10)C4H6: varied concentration and ratio of reagents, synthesis time. The new compound was characterized by using H-1, 1D and 2D F-19 NMR; IR and UV-vis spectroscopy; electro-spray ionization mass spectrometry and DFT calculations. (C) 2016 Elsevier B.V. All rights reserved.

Using ESR spectroscopy, it has been found that the additional paramagnetic centers appear in the (DOEO) 4 [HgBr 4 ] · TCE crystals at temperatures of 5–70 K. The symmetry of their crystal field differs from that observed for charge carriers in a temperature range of 70–300 K. The comparison of the temperature dependences of resistivity with parameters of the ESR spectra makes it possible to assume that the carriers localize at two types of sites differing by the crystalline surrounding at 70 K.

In this work the, intrinsic properties of the ground and excited states of the DOEO0 neutral molecule and the DOEO+ cation are studied; DOEO = [(1,4-dioxane-diyl-2,3-dithio)ethylenedioxytetrathiafulvalene]. The ground-state optimised structures and energies were obtained using the density functional theory (DFT) as approximated by the various functionals (B3LYP, B3PW91, and LSDA) in restricted and unrestricted models for neutral DOEO0 and DOEO+ cation, respectively. The character and energy of the first 30 singlet-singlet electronic transitions were investigated by applying the time-dependent DFT approximations, TD-B3LYP, TD-B3PW91, and TD-LSDA, to the corresponding optimised ground-state geometries. Moreover, excites states were calculated for DOEO dimer with one hole at the TD-B3LYP/3-21 + G(d) level of theory; the initial geometry of the dimer was taken from X-ray data. A comparison is made between the different theoretical methodologies used to study the electronic ground and excited states. We also report the polarised optical conductivity spectra (500-18,000 cm(-1)) and the absorption spectra (400-47,000 cm(-1)) of (DOEO)(4)HgBr4 center dot TCE salt.

Crystals of a new radical-cation salt (DOEO)4[HgBr4] · TCE (I) (DOEO = (1,4-dioxanediyl-2,3-dithio)ethylenedioxotetrathiafulvalene, TCE = 1,1,2-trichloroethane) were synthesized by electrocrystallization method at constant current (i=5×10−6 A/cm2). Crystal structure was studied at room (293 K) and low (30 K) temperatures and was found to consist of the radical-cation layers alternating along the z-axis with tetrahedral HgBr 4 2− anions and TCE molecules. The anion is disordered over three positions at room and over two positions at low temperatures with occupancy factors 87, 11, 2 and 98, 2%, respectively. The poorly occupied positions of the anion are overlapped with positions of the TCE molecule disordered over two equally occupied positions. The DOEO ethylene groups disordered at 293 K were found ordered at 30 K. The conductivity of I exhibits the following peculiarity: in a temperature interval of 120–140 K, the temperature dependence of resistivity has a pronounced maximum.

A new radical-cation salt β-(DOET) 4 CuBr 4 ·PhCl (DOET = (1,4-dioxanediyl-2,3-dithio)ethylene-dithiotetrathiafulvalene) is synthesized by electrocrystallization in the dc mode ( I = 0.12 μA), and its structure is studied. In the structure of the salt, the DOET radical cations are packed in layers parallel to ab . The average charge on DOET is equal to +0.5. The dioxane rings and ethylene groups of DOET, the tetrahedral CuBr 4 2− -anion, and the chlorobenzene molecules are each disordered over two positions with a 50% probability, and the chlorine atoms of chlorobenzene are disordered over four positions with a 25% probability. The salt has semiconducting properties ( E a = 55 meV).

A new charge transfer (DOEO)4HgBr4·TCE salt based on [(1,4-dioxane-diyl-2,3-ditio)ethylenedioxytetrathiafulvalene] (DOEO) and [HgBr4]2− anion was synthesized and characterized by spectral analysis. The structure consists of alternating organic and inorganic layers. The inorganic layers are formed by [HgBr4]2− anions and 1,1,2-trichloroethan (TCE) solvent molecules. The organic layers are built of dimerized DOEO stacks. Polarized reflectance (from 500 to 18,000cm−1) and Raman spectra of single crystals were studied down to the liquid helium temperature. An electronic dispersion in IR spectra was analyzed in terms of the Lorentz model and optical transport parameters were determined. The proposed assignment of vibrational features of (DOEO)4HgBr4·TCE salt was based on ab initio calculations of the normal modes of DOEO0, DOEO+, and TCE molecules. The analysis of the spectra in terms of the isolated dimer model yields reliable estimates of DOEO electron–molecular vibration (e–mv) coupling constants.

A new radical-cation salt beta-(DOET)(4)CuBr4 center dot PhCl(DOET = (1,4-dioxanediyl-2,3-dithio) ethylene-dithiotetrathiafulvalene) is synthesized by electrocrystallization in the dc mode (I = 0.12 mu A), and its structure is studied. In the structure of the salt, the DOET radical cations are packed in layers parallel to ab. The average charge on DOET is equal to +0.5. The dioxane rings and ethylene groups of DOET, the tetrahedral CuBr42 -anion, and the chlorobenzene molecules are each disordered over two positions with a 50% probability, and the chlorine atoms of chlorobenzene are disordered over four positions with a 25% probability. The salt has semiconducting properties (E-a = 55 meV).

An organic metal β-(DOET) 2 FSO 3 · H 2 O based on a novel donor DOET (DOET is (1,4-dioxane-2,3-diyldithio)ethylenedithiotetrathiafulvalene) was synthesized and structurally characterized. Single crystals were prepared by electrochemical oxidation of DOET in the d.c. mode. The salt has a layered structure with the DOET 1/2+ radical cation layers parallel to the ab plane. The FSO 3 − anion is equiprobably disordered over two positions relative to the center of symmetry (1/2, 0, 0). The temperature behavior of conductivity is characteristic of metals in the temperature range from 293 down to 96 K; below 96 K, an increase in resistance is observed.

The stable metal β″-(DOEO)2HSeO4 · H2O I) based on a new donor compound, 3,4-(1,4-dioxanediyl-2,3-dithio)-3′,4′-ethylenedioxo-2,5,2′,5′-tetrathiafulvalene] (DOEO), is synthesized and structurally characterized for the first time. The synthesis is performed by the electrocrystallization technique (direct current density j = 2 × 10−6 A/cm2). The crystals are triclinic, and the unit cell parameters are as follows: a = 5.495(1) Å, b = 9.715(2) Å, c = 16.878(3) Å, α = 83.52(3)°, β = 82.54(3)°, γ = 73.51(3)°, Z = 1, and space group \(P\bar 1\). The salt has a layered structure. The DOEO1/2+ radical cation layers are aligned parallel to the ab planes. The HSeO 4 − · H2O solvated anions are located in channels along the a axis and are disordered over two positions near the center of symmetry (1/2 0 0) with a probability of 50%. The conductivity of the salt is equal to 300–400 Ω−1 cm−1 at room temperature and increases upon cooling to the boiling point of liquid helium (4.2 K) by a factor of 100–200 depending on the sample.

A new radical cation salt based on 4,5-(1,4-dioxanediyl-2,3-dithio)-4′,5′-ethylenedithiotetrathiafulvalene (DOET) with the photochromic anion [Fe(CN)5NO]2−, namely, (DOET)4[Fe(CN)5 NO]1.25(C6H5Cl)0.75, is synthesized. Single crystals of this salt are studied using X-ray diffraction [a = 10.398(2) Å, b = 11.168(2) Å, c = 18.499(4) Å, α = 103.14(3)°, β = 92.80(3)°, γ = 106.02(3)°, V = 1996.3(7) Å3, space group \(P\bar 1\), and Z = 1]. In the structure, radical cation layers alternate with anion layers along the c axis. The centrosymmetric dimers are formed by DOET radical cations in the donor layer with packing of the β type. Like the vast majority of DOET-based salts, the new salt possesses semiconductor properties.

The structures of organic metals (DOET) 4 [Hg 2 Cl 6 ] ( 1 ) and (DOET) 4 [Hg 2 Br 6 ] ( 2 ), where DOET is (1,4-dioxanediyl-2,3-dithio)ethylenedithiotetrathiafulvalene, were established by X-ray diffraction analysis. Compounds 1 and 2 are isostructural, and their crystals have layered structures. The conducting layers formed by the stacked DOET 1/2+ cations alternate with the layers of the [Hg 2 X 6 ] 2– anions (X = Cl, Br). The temperature dependence of the conductivity of salt 1 shows a metallic character in the range of 300—4 K. Compound 2 undergoes the metal—semiconductor phase transition (T M—I ) at 100 K.

The research of supramolecular organisation of organic molecules into nano-or micro-dimensional assemblies is of high relevance for design of new materials for versatile applications and for understanding of the organisation of matter in general.Macroscopic manifestation of self-aggregation can result in ordered gels that include entraped solvent molecules.It is recognised that gelation is based on self -assembly of gelators in solution, leading to supramolecular arrays of specific non-covalent interactions: hydrogen bonds, van der Waals interactions and metal coordination.It is a chalenge to predict gelation on the basis of the constitutional and conformational characteristics of an organic molecule and the properties of the liquid to be gelled.Recently we have shown that chiral bis(amino acid) oxalamides represent a rare group of gelators capable to gel water and various lipophilic organic solvents (Makarevic et al., Chem.Eur.J. 2001, 7, 3328), whereas our new results are related to chiral bis(leucinol)oxalamides exhibiting gelating properties.The crystal structures of both, SS-and rac-bis(leucinol)oxalamide reveal two-dimensional hydrogen bonded networks through oxalamide and alcohol functionalities.X-ray powder diffraction was used to identify an appearance of crystalline phases in gels and xerogels of enantiomeric and racemic samples.In all cases the monoclinic crystalline phase identical to the crystals of SS-enantiomer was found.The high gelating properties of racemic compound might be related by van der Waals interactions between enantiomeric fibres of oposite chirality, whereas molecular organisation in fibres is governed by hydrogen bonds.

A new radical cation salt based on bis(ethylenedithio)tetrathiafulvalene ( BEDT-TTF ) with the tetrahedral anion GaCl 4 − , namely, ( BEDT-TTF ) 4 (GaCl 4 ) 2 · C 6 H 5 CH 3 , has been synthesized. The crystal structure of this salt is determined by X-ray diffraction analysis [ a = 31.757(2) Å, b = 6.8063(3) Å, c = 34.879(2) Å, β = 90.453(4)°, V = 7538.8(7) Å 3 , space group I 2/ c , and Z = 4]. In the structure, the radical cation layers alternate with the anion layers along the c -axis. The anion layers consist of the GaCl 4 − tetrahedra and solvent molecules. The packing of BEDT-TTF molecules in the radical cation layer differs from that in the structure of the known salt ( BEDT-TTF ) 2 GaCl 4 , even though both compounds exhibit semiconductor properties.

A new molecular semiconductor, (Doet) 2 ReO 4 (Doet is (1,4-dioxanediyl-2,3-dithio)ethylenedithiotetrathiafulvalene), is synthesized and examined by X-ray diffraction analysis. The crystal structure of (Doet) 2 ReO 4 is formed by [Doet] +1/2 layers with isle [ReO 4 ] – anions located between them. The Doet radical cations from the adjacent layers are linked by intermolecular hydrogen interactions of the O···H type.