Synthesis and properties of optically active ferrocenylethylindazoles

The stereochemistry of two processes, viz., -ferrocenylalkylation of indazole with optically active S-(+)-1-ferrocenylethanol and the thermal rearrangement of S-(+)-2-N-(ferrocenylethyl)indazole into S-(+)-1-N-(ferrocenylethyl)indazole, was studied. Both reactions proceed stereoselectively.     

Hypercrosslinked polystyrene as a novel type of high-performance liquid chromatography column packing material. Mechanisms of retention

An experimental material, Chromalite 5HGN (Purolite, UK), that represents hypercrosslinked polystyrene as a new type of neutral stationary phase for HPLC was examined. The material contains no functional groups, but is compatible with any kind of nonpolar and highly polar mobile phase, and even with water. It is chemically resistant and thermally stable. When using aqueous organic mobile phases, Chromalite 5HGN works similar to standard C18 reversed-phase packings, but is characterized by much greater hydrophobicity and, sometimes, unusual selectivity. When using nonpolar mobile phases, i.e. under "quasi normal-phase" conditions, the retention is mostly governed by the interactions between pi-electronic systems of the adsorbent and adsorbate. Adding highly polar, even hydrophilic solvents into the mobile phase, leads to a shift of retention times toward the "reversed-phase" kind of chromatography, which gives an additional possibility in fine tuning the column selectivity.     

Branching Fraction Measurements of the SM Higgs with a Mass of 160 GeV at Future Linear e + e − Colliders

Assuming an integrated luminosity of 500 fb^–1 and a center-of-mass energy of 350 GeV, we examine the prospects for measuring branching fractions of a Standard Model-like Higgs boson with a mass of 160 GeV at the future linear e⁺e^–collider TESLA when the Higgs boson is produced via the Higgsstrahlung mechanism, e⁺e^– HZ. The Higgs boson mass chosen close to the W pair threshold covers a mass regime with complicated background structures. We study in detail including some detector responds the precisions achievable for the branching fractions of the Higgs boson into WW^(*), ZZ^* and , whereas the measurement of BF(H ) remains a great challenge. Expectations for the total Higgs width are discussed using either the BF(Z ZZ^*) measurement of this study and the expected error for the inclusive Higgsstrahlung cross section or in addition the precise cross section expected for the weak boson fusion process, e⁺e^– v H, or W,Z-universality.     

Physicochemical and adsorption properties of hypercross‐linked polystyrene with ultimate cross‐linking density

The paper describes unexpected properties of hypercross‐linked polystyrenes with ultimate cross‐linking degrees of 300, 400, and 500%, where three, four, or five methylene links, respectively, could bind each polystyrene phenyl ring to its spacious neighbors. The polymers exhibit a strong electron spin resonance signal, unusual spectra in IR, UV, and visible ranges, and they are not typical dielectrics. The nonfunctionalized hypercross‐linked polymers absorb significant amounts of inorganic acids, salts, and bases due to interactions of protons or other cations with electron‐donating fragments of the aromatic network with the high extent of mutual connectivity and also due to dispersion interactions of anions with the polymer matrix.     

Facile and convenient synthesis of aryl hydrazines via copper-catalyzed C–N cross-coupling of aryl halides and hydrazine hydrate

An efficient and convenient method for the synthesis of aryl hydrazines has been developed via copper-catalyzed cross-coupling of aryl bromides and hydrazine with a readily accessible ligand and water as a solvent. The multigram scale procedure is applicable to aryl bromides bearing both moderately electron-donating and electron-withdrawing substituents in the aromatic nucleus. No column chromatography is required to obtain aryl hydrazine hydrochlorides in good yields.     

Excess energy in the electroexplosive nanopowders

Research on Chemical Intermediates - The electroexplosive route for nanopowders production is a rapidly occurring nonequilibrium process under the action of high power density energy. The...     

Rheological properties of acrylonitrile—acrylamide—styrene copolymer solutions synthesized by classical and controlled radical polymerizations

Russian Chemical Bulletin - The results of a comparative study of the rheological properties of acrylonitrile copolymers solutions synthesized by classical and controlled radical polymerizations in...     

Enantio- and diastereoselective Darzens condensations

A cobalt(salen) complex has been shown to catalyse the asymmetric Darzens condensation between α-haloamides and aldehydes, allowing both the relative and absolute stereochemistry of the epoxy-amide products to be controlled. Under optimal conditions, cis-epoxides can be obtained diastereoselectively with up to 50% enantiomeric excess, whilst by changing the leaving group and base, trans-epoxides can be produced diastereoselectively with up to 43% enantiomeric excess.     

Use of the hyper-crosslinked polystyrene sorbents “Styrosorb” for solid phase extraction of phenols from water

The analytical HPLC procedure for the quantitation of trace amounts of phenol and chlorophenols in aqueous media has been supplemented with the on-line preconcentration of phenols in a sorption cartridge packed with microporous hyper-crosslinked polystyrene. The cartridge is coupled in succession with a reversed-phase analytical column, which is operated isocratically in an aqueous acetonitrile eluent (1:1, v/v). Phenol concentrations down to 0.5 μg/l can be detected using a simple 254 nm UV detector. Biporous hyper-crosslinked polystyrene-type sorbents were shown to effectively purify about 100 bed volumes of water from phenol under neutral or acidic conditions and linear flow rates up to 4 cm/min, which could be of great practical importance. Rapid and quantitative elution of sorbates from the hyper-crosslinked polystyrene materials is facilitated by the unique ability of the latter to additionally swell with organic or aqueous-organic eluents applied.