Rashba split surface states in BiTeBr

Within density functional theory, we study bulk band structure and surface states of BiTeBr. We consider both ordered and disordered phases which differ in atomic order in the Te-Br sublattice. On the basis of relativistic ab-initio calculations, we show that the ordered BiTeBr is energetically preferable as compared with the disordered one. We demonstrate that both Te- and Br-terminated surfaces of the ordered BiTeBr hold surface states with a giant spin-orbit splitting. The Te-terminated surface-state spin splitting has the Rashba-type behavior with the coupling parameter \alpha_R ~ 2 eV\AA.Comment: 8 pages, 7 figure

Many-body effects on the Rashba-type spin splitting in bulk bismuth tellurohalides

We report on many-body corrections to one-electron energy spectra of bulk bismuth tellurohalides---materials that exhibit a giant Rashba-type spin splitting of the band-gap edge states. We show that the corrections obtained in the one-shot $GW$ approximation noticeably modify the spin-orbit-induced spin splitting evaluated within density functional theory. We demonstrate that taking into account many-body effects is crucial to interpret the available experimental data.Comment: 6 pages, 1 figur

The redox transformations and nucleophilic replacements as possible metabolic reactions of the drug “Triazaverin”. The chemical modeling of the metabolic processes

As a model of metabolic transformations of antiviral drug “Triazaverin” and its analogues‑2-alkylthio‑6-nitro‑1,2,4-triazolo[5,1-c][1,2,4]triazine‑7-ones 1a-d examined the oxidation of alkylthio groups to the corresponding sulfoxides 2a-d and sulfones 3a-d, as well as the process of nucleophilic substitution sulfonyloxy group of cysteine and cysteamine with the formation of compounds 5 and 6

Tests of Scintillator Tiles for the Technological Prototype of Highly Granular Hadron Calorimeter

A new technological prototype of the highly granular hadron calorimeter for future collider experiments is being developed by the CALICE collaboration. The proposed baseline design of active elements considers scintillator tiles with a silicon photomultiplier readout. The light yield and uniformity of response of two tiles with dimple geometry from different producers were measured. The technology proposed for the ILD detector was used: each tile was individually wrapped in the reflecting foil and the SiPm was coupled directly to the dimple side of the scintillator tile. The measured response to minimum ionizing particle is almost twice better for BICRON408 scintillator than for polystyrene-based scintillator, while the estimated uniformity of response is better for the polystyrene-based scintillator tile produced by injection molding

Study of Scintillator Strip with Wavelength Shifting Fiber and Silicon Photomultiplier

The performance of the $200\times2.5\times1$ cm$^3$ plastic scintillator strip with wavelength shifting fiber read-out by two novel photodetectors called Silicon PhotoMultipliers (SiPMs) is discussed. The advantages of SiPM relative to the traditional multichannel photomultiplier are shown. Light yield and light attenuation measurements are presented. This technique can be used in muon or calorimeter systems.Comment: 9 pages, 5 figure

Non-natural nucleosides based on 1,2,4-triazolo[5,1-c][1,2,4]triazin-4(6H)- ones

Two regioselective methods for the synthesis of nucleosides in the series of 3-phenyl- and 3- ethoxycarbonyl-1,2,4-triazolo[5,1-c][1,2,4]triazin-4-ones were developed. The first route involves a Vorbrüggen glycosylation reaction. The second one is based on condensation of 1,2,4- triazolo[5,1-c][1,2, 4]triazin-4-one sodium salts with protected 1-bromo-sugar derivatives

Cyclotrimerization of 3-R-1,2,4-triazin-5(4H)-ones with cyclic ketones

New heterocyclic tetracyclic systems were synthesized. Interaction between 3-R-1,2,4-triazin-5(4H)-ones and cyclic ketones under acidic conditions leads to the formation of zwitterion derivatives of 5,6,7,8,9,10,11,12-octahydro-[1,2,4] triazino[1,6- f ]phenanthridine and 1,2,3,6,7,8-hexahydro-bicyclopenta[b,d] pyrido[1,2- f ][1,2,4]triazine. © 2010 Verlag der Zeitschrift für Naturforschung, Tübingen

Synthesis of acyclic nucleoside analogues by one-step Vorbrüggen glyco-sylation of 1,2,4-triazolo[1,5-a]pyrimidine-7-ones

New analogues of acyclovir have been prepared by reacting 1,2,4 -triazolo[1,5-a]pyrimidin-7-ones 1а-i and (2-acetoxyethoxy)methyl acetate 2 in the presence of trimethylsilyl trifluoromethanesulfonate as a catalyst. The interaction between the compounds 1а-е and 2 has led to a mixture of N3 and N4 isomers. In contrast, the reaction of compounds 1g-i and 2 proceeded selectively to form N3 isomers. In the case of compounds 1a-c the predominant product is the one with the acyclic moiety in azine ring (N4 isomer). Interaction between 1d-f and 2 has led to mixtures comprising mainly N3 isomer. It has been found that the ratio of glycosylation products 1 and 2 are thermodynamically controlled. The structure of the obtained compounds has been proved by 1Н, 13С, two-dimensional 1Н-13С NMR spectroscopy and X-ray analysis

Spin-spin coupling constants 13C-15N and 1H-15N in the investigation of azido-tetrazole tautomerism in a series of 2-azidopyrimidines

A new method was developed for the investigation of an azido-tetrazole equilibrium based on using a complex analysis of 13C-15N and 1H-15N spin-spin coupling constants. The use of this approach became possible due to the selective inclusion of 15N isotopes into the structures of 2-azidopyrimidines and their cyclic analogs tetrazolo[1,5-a]pyrimidines. © 2013 Springer Science+Business Media New York

A rational protocol for the synthesis of 1-(2-pyridyl)isoquinolines

Aza-Diels-Alder reaction between 3-(2-pyridyl)-1,2,4-triazines and 1-morpholinocyclohexene followed by aromatization of the cyclohexene moiety affords 1-(2-pyridyl)isoquinolines. Crystal structures of two tetrahydroisoquinolines were confirmed by X-ray diffraction analysis. © 2013 Mendeleev Communications. All rights reserved