Optical properties of new organic conductors based on the BEDT-TSeF molecule (the κ-(BETS)4Hg2.84Br8 superconductor and κ-(BETS)4Hg3Cl8 Metal) in the range 300–15 K

Polarized reflectance and optical conductivity spectra of single crystals of two new isostructural organic conductors based on the BEDT-TSeF molecule, namely, the κ-(BETS)₄Hg_2.84Br₈ superconductor (T _c =2 K) and the κ-(BETS)₄Hg₃Cl₈ metal, which undergoes a smooth transition to the dielectric state near 35 K, have been obtained in the spectral region 700–6500 cm⁻¹ at temperatures of 300–15 K. At 300 K, the spectra of both compounds are nearly identical and differ from the Drude spectrum characteristic of metals. The nature of the observed difference is discussed, and the spectra are described in terms of a cluster approach with inclusion of electron-electron correlations in the Hubbard approximation combined with the Drude model. The parameters of the theory were determined, including the electron transfer integrals between molecules in a cluster. The spectra in the conducting plane of the crystals were found to be essentially anisotropic, which should be assigned to specific features of in-plane interaction between molecules. The spectra of the superconductor and the metal become increasingly different as the temperature is lowered. The spectra of the metal obtained for T<150 K exhibit splitting of the broad electronic maximum in the mid-IR region into two bands, which is accompanied by a splitting of a vibronic feature deriving from electron interaction with intramolecular BETS vibrations of ν₃(A _g ) symmetry. No such splitting is observed in the superconductor spectra with decreasing temperature. __________ Translated from Fizika Tverdogo Tela, Vol. 46, No. 11, 2004, pp. 1921–1929. Original Russian Text Copyright ? 2004 by Vlasova, Drichko, Petrov, Semkin, Zhilyaeva, Lyubovskaya, Olejniczak, A. Kobayashi, H. Kobayashi.     

The catalytic reactions of triethyl- and triethoxy-silane with unsaturated sulphides

The hydrosilylation of mono- and di-alkenyl sulphides of the type RS(CH₂)_nCH=CH₂ (R = C₂H₅, CH₂=CH, CH₂=CHCH₂, C₃H₇, n = 0, 1 and 4) by triethyl- and triethoxy-silane, catalyzed by H₂PtCl₆·6 H₂O, (Ph₃P)₃RhCl and (PhCN)₂PdCl₂·Ph₃P, has been studied. The addition of hydrosilane to the double bond of alkenyl sulphide leads to a mixture of two isomeric monoadducts. The hydrosilane can cleave the C---S bond of the initial sulphides giving the corresponding derivatives of thiosilanes, X₃SiS(CH₂)_nCH=CH₂ (X = C₂H₅, C₂H₅O). Hydrosilylation of alkenyl sulphides is accompanied by some side reactions such as dehydrocondensation, reduction and polymerization. The effect of the catalyst nature, the structure of hydrosilane and alkenyl sulphide on the reaction route has been investigated.     

Structure,tautomerism, and transformations of β-(3-nitro-2-pyridyl)- and β-(3-nitro-4-pyridyl)pyruvic acid esters

It was shown by means of IR, UV, and PMR spectra that -(3-nitro-2-pyridyl)pyruvic acid esters are practically completely enolized in the crystal state and in solution; ethyl -(3-nitro-4-pyridyl)pyruvate has an enol structure in the crystalline state and in pyridine solution but exists as a mixture of keto and enol forms in low-polarity solvents.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 389–393, March, 1974.     

Convergence of series with respect to generalized Haar systems

. . . . , L _p[0, l], 1 >p <, .     

Immobilization of proteolytic enzymes trypsin and α-chymotrypsin to cellulose matrix

Trypsin and α-chymotrypsin were immobilized on a microcrystalline cellulose matrix by adsorption interaction with cellulose. The adsorption of enzymes was determined as a function of their concentration and the pH of solutions. Mechanisms of enzyme binding to functional groups of cellulose were suggested.     

Reaction of ethylene oxide with n-phenylated isomers of 1,2,4-triazoline-3-thione and 1-phenyltetrazoline-5-thione

It is demonstrated that ethylene oxide forms N--hydroxyethyl derivatives of the corresponding triazolin-3-ones in the reaction with 1-phenyl- and 4-phenyl-1,2,4-triazolin-3-thiones and with 3--hydroxyethylthio derivatives of 1-phenyl- and 4-phenyl-1,2,4-triazole in acetic acid. 1-Phenyltetrazolin-5-thione reacts similarly with ethylene oxide. Under the influence of ethylene oxide, 2-methyl-4-phenyl-1,2,4-triazolin-3-thione is converted to 2-methyl-4-phenyl-1,2,4-triazolin-3-one.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 700–703, May, 1971.     

Synthesis and properties of low-molecular-weight copolymers of acrylamide with 2-acrylamido-2-methylpropanesulfonic acid,as potential drug carriers

Nontoxic water-soluble low-molecular-weight (MW 14 000–36 000 Da) copolymers of acrylamide with 2-acrylamido-2-methylpropanesulfonic acid, containing from 17.3 to 37.6 mol % sulfonate-containing monomeric units, were synthesized by heterophase radical polymerization in isopropanol or ethanol at 50°C with azobis(isobutyronitrile) as an initiator. Original Russian Text M.V. Solovskii, M.Yu. Eropkin, E.M. Eropkina, A.V. Slita, M.Yu. Smirnova, E.N. Vlasova, E.B. Tarabukina, A.I. Amirova, 2007, published in Zhurnal Prikladnoi Khimii, 2007, Vol. 80, No. 10, pp. 1674–1678.     

Clathrate formation and phase transitions in β-hydroquinone

Clathrate thermodynamic stability conditions and the phase transitions associated with either the orientational ordering of the guest molecules or with the condensation of the guest molecules in the host lattice are investigated by means of the common microscopic model. The theory proposed describes the thermodynamic properties of -hydroquinone (Q ) clathrates. The dielectric constant (T) was measured experimentally inQ ·CH₃OH andQ ·SO₂ in the temperature range from 4.2 to 300 K and the phase transitions were found. It is shown that the theory qualitatively explains the experimental data obtained.Dedicated to Professor H. M. Powell.     

Pyrylia[2,3-d]pyrimidine salts

The condensation of 2-amino- and 2-methylthio-4, 6-dihydroxypyrimidines and barbituric and thiobarbituric acids with -diketones in strong acids leads to pyrylia[2,3-d]pyrimidine salts, which on treatment with ammonia or aniline are converted to pyrido[2,3-d]pyrimidines or to 8-phenylpyrido[2,3-d]pyrimidinium salts, respectively.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1484–1486, November, 1977.