L.I. Buravov

Resistance and magnetoresistance anomaly in a new stable organic metal (ET)2TlHg(SCN)4

Abstract A new organic metal (ET) 2 TlHg(SCN) 4 has been synthesized. The X-ray study shows the compound to be isostructural to (ET) 2 MHg(SCN) 4 salts with M = K, NH 4 and Rb. The resistance and magnetoresistance measurements show anomalous behaviour at low temperature which may be attributed to spin-density-wave instability. Shubnikov-de Haas oscillations have also been observed at low temperature.

Molecular metals based on radical cation salts of ET and some its analogues with the photochromic nitroprusside anion, [Fe(CN)5NO]2-

Abstract A series of electroconducting radical cation salts based on ET, BEDO and EDT with the photochromic nitroprusside anion has been synthesized. Their crystal structures and transport properties have been studied. The salts of the (ET) 4 M[Fe(CN) 5 NO] 2 (M=Na,K,NH 4 ,Tl,Rb,Cs) composition are isostructural and exhibit metallic behaviour down to helium temperatures.

Novel organic superconductor κ-(ET)2Cu[N(CN)2]Cl0.5Br0.5 with Tc∼11.3 K

κ-(ET)2Cu[N(CN)2]Cl0.5Br0.5, a new organic superconductor (Tc ∼ 11.3 K at ambient pressure) has been synthesized. Its X-ray study has been undertaken.

[Ni(dddt)2]3(HSO4)2, the first metal among the M(ddt)2 salts

Abstract The first metal, [Ni(dddt)2]3(HSO4)2, among the class of M(dddt)2 cation salts has been obtained. Its structure and conducting properties have been studied. [Ni(dddt)2]3(HSO4)2 has been found to be isostructural to the (ET)3(HSO4)2 salt and their conducting properties are compared. [Ni(dddt)2]3(HSO4)2 retains its metallic state to lower temperatures (∼ 25 K) than (ET)3(HSO4)2 (∼ 130 K).

Effect of electrocrystallization medium on quality, structural features, and conducting properties of single crystals of the (BEDT-TTF)4AI[FeIII(C2O4)3]·G family

A modified procedure for the electrocrystallization of organic conductors with paramagnetic anions of the (BEDT-TTF)4AI[MIII(C2O4)3]·G family has been proposed. It is found that single crystals of different phases of the family can be prepared if the electrocrystallization medium is represented by the mixture of 1,2,4-trichlorobenzene (or 1,3-dibromobenzene), 96% ethanol and different solvents (G), only the latter being included into the composition of the resulting salts as neutral guest molecules (G = benzonitrile, fluorobenzene, chlorobenzene, 1,2-dichlorobenzene, bromobenzene, nitrobenzene). Using this approach, a number of known and new BEDT-TTF salts with the tris(oxalato)ferrate anion have been synthesized. Among them, there are superconducting crystals of monoclinic β′′-series with different guest solvents (G) and their mixtures. For the first time, crystals of a triclinic phase (G = 1,2-dibromobenzene), with alternating α- and ‘pseudo-κ’ BEDT-TTF layers and metallic behaviour down to 1.5 K, were obtained. Additionally, monoclinic crystals having another stoichiometry and α-type donor packing were prepared.

Molecular metals based on Pd(dddt)2 and Ni(dddt)2 complexes

Abstract A series of electroconducting cationic salts based on the Pd(dddt) 2 and Ni(dddt) 2 complexes has been synthesized. The first stable molecular metals have been found among the M(dddt) 2 salt family.

π-Donor BETS Based Bifunctional Superconductor with Polymeric Dicyanamidomanganate(II) Anion Layer : κ-(BETS)2Mn[N(CN)2]3

Crystals of the bis(ethylenedithio)tetraselenafulvalene (BETS) radical cation salt with dicyanamidomanganate(II) anion, kappa-(BETS)2Mn[N(CN)2]3, were synthesized, which combine conducting and magnetic properties at ambient pressure and are superconducting (Tc approximately/= 5 K) at a moderate pressure of 0.3 kbar.

Syntheses, structures, and electroconductivity of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and bis(methylenedithio)tetrathiafulvalene (BMDT-TTF) salts with cobalt 8,8′-dichloro-3,3′-bis(1,2-dicarbollide)

Radical cation salts of bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) and bis(methylenedithio)tetrathiafulvalene (BMDT-TTF) with the 8,8′-dichloro derivative of cobalt bis(1,2-dicarbollide) (BEDT-TTF)2[8,8′-Cl2-3,3′-Co(1,2-C2B9H10)2] (1) and (BMDT-TTF)4[8,8′-Cl2-3,3′-Co(1,2-C2B9H10)2] (2) were synthesized and their crystal structures and electrocon-ducting properties were determined. The synthesized radical cation salts are semiconductors with the conductivity σ293 = 1.5 and 2.0 Ohm−1 cm−1, respectively. A decrease in the size of the substituent in a series of (BEDT-TTF)2[8,8′-X2-3,3′-Co(1,2-C2B9H10)2] and (BMDT-TTF)4[8,8′-X2-3,3′-Co(1,2-C2B9H10)2] (X = I, Br, Cl) results in the compression of the anion sublattice of the crystal and compaction of the radical cation packing of the conducting layer, which, in turn, increases the conductivity of the crystals.

Structure and magnetotransport properties of the new quasi-two-dimensional molecular metal β″-(BEDT-TTF)4H3O[Fe(C2O4)3] · C6H4Cl2

The β″-(BEDT-TTF)4AI[MIII(C2O4)3] · G(AI=NH4+, H3O+, K+, Rb+; MIII=Fe, Cr; G = “guest” solvent molecule) family of layered molecular conductors with magnetic metal oxalate anions exhibits a pronounced dependence of the conducting properties on the type of neutral solvent molecules introduced into the complex anion layer. A new organic dichlorobenzene (C6H4Cl2)-containing conductor of this family, namely, β″-(BEDT-TTF)4H3O[Fe(C2O4)3] · C6H4Cl2, is synthesized. The structure of the synthesized single crystals studied by X-ray diffraction is characterized by the following parameters: a = 10.421(1) Å, b= 19.991(2) Å, c= 35.441(3) Å, β = 92.87(1)°, V= 7374(1) Å3, space groupC2/c, and Z = 4. In the temperature range 0.5&2-300 K, the conductivity of the crystals is metallic without changing into a superconducting state. The magnetotransport properties of the crystals are examined in magnetic fields up to 17 T at T = 0.5 K. In fields higher than 10 T, Shubnikov-de Haas oscillations are detected, and the Fourier spectrum of these oscillations contains two frequencies with maximum amplitudes of about 80 and 375 T. The experimental results are compared with the related data obtained for other phases of this family. The possible structural mechanisms of the effect of a guest solvent molecule on the transport properties of the β″-(BEDT-TTF)4AI[MIII(C2O4)3] · G crystals are analyzed.

Structure and magnetotransport properties of the new quasi-two-dimensional molecular metal {beta} Double-Prime -(BEDT-TTF){sub 4}H{sub 3}O[Fe(C{sub 2}O{sub 4}){sub 3}] {center_dot} C{sub 6}H{sub 4}Cl{sub 2}

The β″-(BEDT-TTF)4AI[MIII(C2O4)3] · G(AI=NH4+, H3O+, K+, Rb+; MIII=Fe, Cr; G = “guest” solvent molecule) family of layered molecular conductors with magnetic metal oxalate anions exhibits a pronounced dependence of the conducting properties on the type of neutral solvent molecules introduced into the complex anion layer. A new organic dichlorobenzene (C6H4Cl2)-containing conductor of this family, namely, β″-(BEDT-TTF)4H3O[Fe(C2O4)3] · C6H4Cl2, is synthesized. The structure of the synthesized single crystals studied by X-ray diffraction is characterized by the following parameters: a = 10.421(1) Å, b= 19.991(2) Å, c= 35.441(3) Å, β = 92.87(1)°, V= 7374(1) Å3, space groupC2/c, and Z = 4. In the temperature range 0.5&2-300 K, the conductivity of the crystals is metallic without changing into a superconducting state. The magnetotransport properties of the crystals are examined in magnetic fields up to 17 T at T = 0.5 K. In fields higher than 10 T, Shubnikov-de Haas oscillations are detected, and the Fourier spectrum of these oscillations contains two frequencies with maximum amplitudes of about 80 and 375 T. The experimental results are compared with the related data obtained for other phases of this family. The possible structural mechanisms of the effect of a guest solvent molecule on the transport properties of the β″-(BEDT-TTF)4AI[MIII(C2O4)3] · G crystals are analyzed.