STUDY OF COMPOSITION FILM SYSTEM PB-SE AND CHANGE OF STRUCTURE UNDER TEMPERATURE ACTION

2018 ◽  
Vol 20 (5-6) ◽  
pp. 129-140
Author(s):  
A. G. Razina ◽  
V. A. Kazakov ◽  
A. A. Ashmarin ◽  
V. D. Kochakov
Keyword(s):  
Photoelectron Spectroscopy ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Auger Spectroscopy ◽  
Structural Features ◽  
Phase Synthesis ◽  
X Ray ◽  
Electron Auger Spectroscopy ◽  
Temperature Action ◽  
Electron Auger

The Pb-Se film systems were obtained by solid-phase synthesis and investigated by Xray diffraction and X-ray photoelectron spectroscopy, electron Auger spectroscopy. It was found that the films are heterogeneous in structure and composition. To study the structural features under the influence of temperature, Raman spectra of samples at temperatures of 300 K and 373 K were investigated.

scholarly journals Structure-Acid Lability Relationship of N-alkylated α,α-dialkylglycine Obtained via a Ugi Multicomponent Reaction

Molecules ◽  
2021 ◽  
Vol 26 (1) ◽  
pp. 197
Author(s):  
Iván Ramos-Tomillero ◽  
Marisa K. Sánchez ◽  
Hortensia Rodríguez ◽  
Fernando Albericio
Keyword(s):  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Structural Features ◽  
Amide Bond ◽  
Acidic Media ◽  
Phase Synthesis ◽  
Acyl Chains ◽  
Cyclic Compounds ◽  
Relationship Of ◽  
Fine Tune

Using the classical Ugi four-component reaction to fuse an amine, ketone, carboxylic acid, and isocyanide, here we prepared a short library of N-alkylated α,α-dialkylglycine derivatives. Due to the polyfunctionality of the dipeptidic scaffold, this highly steric hindered system shows an interesting acidolytic cleavage of the C-terminal amide. In this regard, we studied the structure-acid lability relationship of the C-terminal amide bond (cyclohexylamide) of N-alkylated α,α-dialkylglycine amides 1a–n in acidic media and, afterward, it was established that the most important structural features related to its cleavage. Then, it was demonstrated that electron-donating effects in the aromatic amines, flexible acyl chains (Gly) at the N-terminal and the introduction of cyclic compounds into dipeptide scaffolds, increased the rate of acidolysis. All these effects are related to the ease with which the oxazolonium ion intermediate forms and they promote the proximity of the central carbonyl group to the C-terminal amide, resulting in C-terminal amide cleavage. Consequently, these findings could be applied for the design of new protecting groups, handles for solid-phase synthesis, and linkers for conjugation, due to its easily modulable and the fact that it allows to fine tune its acid-lability.

scholarly journals Hydrate of 2,3:4,5-di-O-isopropylidene-β-D-arabino-hexos-2-ulo-2,6-pyranose as new crystalline reagent in the preparation of Amadori derived peptides

2010 ◽  
Vol 8 (1) ◽  
pp. 28-33 ◽  
Author(s):  
Piotr Stefanowicz ◽  
Joanna Batorska ◽  
Monika Kijewska ◽  
Hubert Bartosz-Bechowski ◽  
Zbigniew Szewczuk ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Nmr Spectroscopy ◽  
High Resolution ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Crystalline Hydrate ◽  
Phase Synthesis ◽  
X Ray ◽  
Independent Molecules ◽  
Stable Reagent

AbstractWe established, that crystalline hydrate of 2,3:4,5-di-O-isopropylidene-β-D-arabino-hexos-2-ulo-2,6-pyranose is a new, convenient and stable reagent for solid phase synthesis of peptide derived Amadori products. The structure of the title compound was studied by X-ray analysis, NMR spectroscopy, and high resolution ESI-MS. The crystal structure indicated the existence of two symmetry-independent molecules that were not connected with hydrogen bonds. A comparison with previously reported 2,3:4,5-di-O-isopropylidene-β-D-fructopyranose revealed, that these two compounds are isostructural.

scholarly journals Структура и термодинамические свойства SmGaGe-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=-

2020 ◽  
Vol 62 (2) ◽  
pp. 332
Author(s):  
Л.Т. Денисова ◽  
М.С. Молокеев ◽  
Л.А. Иртюго ◽  
В.В. Белецкий ◽  
Н.В. Белоусова ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Phase Synthesis ◽  
High Temperature Heat Capacity ◽  
X Ray ◽  
Temperature Heat

SmGaGe2O7 has been prepared by solid-phase synthesis in air at temperatures from 1273 to 1473 K using the Sm2O3, Ga2O3, and GeO2 oxides as starting materials. The structure of the studied germanate was determined by X-ray diffraction (space group P2_1 / c; a = 7.18610(9) Angstrem, b = 6.57935(8) Angstrem, c = 12.7932(2) Angstrem). Its high-temperature heat capacity has been measured by differential scanning calorimetry. The obtained experimental dependence C_p = f (T) has been used to evaluate the thermodynamic properties of the compound.

scholarly journals FORMATION OF MG2SI THIN FILMS ON SI (111) AND THEIR RESEARCH BY EOS AND EELS

2021 ◽  
pp. 30-34
Author(s):  
DMITRIY VLADIMIROVICH FOMIN ◽  
◽  
NIKITA SERGEEVICH NOVGORODTSEV ◽  
DMITRIY OLEGOVICH STRUKOV ◽  
ALEXEY VYACHESLAVOVICH POLYAKOV ◽  
...  
Keyword(s):  
Thin Film ◽  
Vacuum Chamber ◽  
Solid Phase ◽  
Auger Spectroscopy ◽  
Magnesium Silicide ◽  
Characteristic Energy ◽  
Electron Auger Spectroscopy ◽  
High Vapor ◽  
Electron Auger

The paper presents information on the results of the formation of a thin Mg2Si film on a silicon substrate by solid-phase epitaxy in an ultrahigh-vacuum chamber of the PHI model 590 device. There are a number of difficulties in the formation of magnesium silicide films due to the low condensation coefficient and high vapor pressure. Effective methods for the formation of Mg2Si are currently being sought. As a result of our experiment, a thin film was obtained, which was studied in-situ by the method of electron Auger spectroscopy and spectroscopy of characteristic energy losses by electrons. Analysis of the Auger electron spectrum showed the presence of magnesium and silicon atoms in the composition of the formed film. From the analysis of the EELS spectra, it was found that a thin film of silicide magnesium was formed.

Solid-Phase Synthesis of KNaSO4 in a Thermal X-Ray Machine Followed by a Study of the Synthesis Product during Cooling

2021 ◽  
Vol 47 (2) ◽  
pp. 181-185
Author(s):  
O. Yu. Shorets ◽  
S. K. Filatov ◽  
V. A. Firsova ◽  
R. S. Bubnova
Keyword(s):  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Synthesis Product ◽  
Phase Synthesis ◽  
X Ray

scholarly journals Using of mechanoactivation for preparation of cerium-containing solid solutions based on zircon

2021 ◽  
Vol 12 (2-2021) ◽  
pp. 66-71
Author(s):  
V. Yu. Vinogradov ◽  
◽  
A. M. Kalinkin ◽  
V. Ya. Kuznetsov ◽  
◽  
...  
Keyword(s):  
Solid Solutions ◽  
Zirconium Oxide ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Planetary Mill ◽  
Molar Ratio ◽  
Phase Synthesis ◽  
X Ray ◽  
Cerium Content ◽  
Zircon Structure

Solid-phase synthesis of cerium-containing solid solutions based on ZrSiO4 was described. The synthesis was carried out using mechanical activation of a mixture consisting of zirconium oxide and hydrated amorphous silica with the addition of cerium oxide at a molar ratio of ZrО2:SiО2:CeО2 equal to 0.95:1.00:0.05. The mechanically activated in a centrifugal planetary mill mixture of reagents was calcined in the temperature range of 1200–1600 °C for 3 hours, which was accompanied by the essentially complete synthesis of zircon. The cerium content in the zircon structure was calculated from X-ray powder diffraction data.

Qualitative Analysis of Solid Phase Synthesis Reaction Products by X-ray Spectrometry

1997 ◽  
Vol 3 (6) ◽  
pp. 520-529 ◽  
Author(s):  
Robert A. Carlton ◽  
Edward Orton ◽  
Charles E. Lyman ◽  
James E. Roberts
Keyword(s):  
Qualitative Analysis ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Analytical Techniques ◽  
Parallel Synthesis ◽  
Specimen Preparation ◽  
Reaction Products ◽  
Phase Synthesis ◽  
X Ray ◽  
Synthetic Transformation

Abstract: A novel method for the synthesis of polypeptides using polystyrene/divinylbenzene copolymers as solid supports has drawn the attention of medicinal, pharmaceutical, and agricultural chemists because of its utility in combinatorial chemistry and parallel synthesis. In this method, arrays of solid-phase organic synthesis experiments are conducted simultaneously thereby enabling the preparation of large numbers of novel compounds over a short time period. The analysis of organic compounds attached to polymer supports presents unique challenges to chemists. This study presents some results of the application of energy-dispersive X-ray spectrometry (EDS) in the environmental scanning electron microscope (ESEM) to this problem. EDS in the ESEM has the advantages of minimal sample size, speed, and simplicity because the analyses are performed without special specimen preparation. The progress of a two-step synthetic transformation was followed using EDS-ESEM by the presence of a sulfur peak in the first synthetic step and by a bromine peak in the second step. The synthetic products were also evaluated by infrared spectroscopy and by elemental analysis (ion chromatography). The agreement of the qualitative analysis among all three techniques was good. Analysis by EDS-ESEM not only complements current analytical techniques in solid phase synthesis; it also provides insight into the details of the synthetic transformation.

scholarly journals Impedance Spectroscopy of Nickel-Containing Solid Solutions of CaCu3Ti4O12

2020 ◽  
pp. 499-510
Author(s):  
Nikolay A. Sekushin ◽  
Maria M. Ignatova ◽  
Nadezhda A. Zhuk
Keyword(s):  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Synthesis Method ◽  
Impurity Phase ◽  
Chemical Bonds ◽  
Variable Electric Field ◽  
Phase Synthesis ◽  
Direct Electric Current ◽  
X Ray ◽  
Concentration Interval

Samples of CaCu3Ti4-4хNi4хO12-δ. were obtained by solid phase synthesis method. X-ray diagrams of all preparations show trace amounts of the impurity phase of copper oxide(II), at x ≥ 0.04 the impurity CaTiO3 reflexes are shown. Admixtures of nickel-containing phases in samples in all investigated concentration interval by X-ray analysis and electronic scanning microscopy are not fixed. It is established that the polarization processes in the samples are carried out at different speeds by two mechanisms. As a result of modeling using two equivalent schemes, it was found that the homogeneity of samples with growth x decreases, in the sample CaCu3Ti4-4хNi4хO12-δ (х = 0.03) polarization proceeds three times faster than in x = 0.06. The sample CaCu3Ti3.88Ni0.12O12-δ conducts direct electric current better and polarizes faster in a variable electric field than x = 0.06. The activation energy of the samples is practically the same: 0.491 (x = 0.03) and 0.499 eV (x = 0.06). After 350 °C the homogeneity of the material deteriorates, which indicates a possible disorder of the structure or a break in the chemical bonds

scholarly journals Solid-phase synthesis and structural characterisation of phosphoroselenolate-modified DNA: a backbone analogue which does not impose conformational bias and facilitates SAD X-ray crystallography

2019 ◽  
Vol 10 (47) ◽  
pp. 10948-10957 ◽  
Author(s):  
Patrick F. Conlon ◽  
Olga Eguaogie ◽  
Jordan J. Wilson ◽  
Jamie S. T. Sweet ◽  
Julian Steinhoegl ◽  
...  
Keyword(s):  
Solid Phase Synthesis ◽  
Tertiary Structure ◽  
Solid Phase ◽  
Phase Synthesis ◽  
X Ray ◽  
Structural Characterisation ◽  
X Ray Crystallography ◽  
Modified Dna

Stable selenium-modified DNA which maintains the native tertiary structure has been prepared under automated conditions enabling SAD X-ray crystallography.

scholarly journals Синтез, структура и теплофизические свойства апатитов Pb-=SUB=-1-x-=/SUB=-Bi-=SUB=-x-=/SUB=-(GeO-=SUB=-4-=/SUB=-)-=SUB=-2+x-=/SUB=-VO-=SUB=-4-=/SUB=-)-=SUB=-4-x-=/SUB=- (x=0-3) в области 350-950 K

2020 ◽  
Vol 62 (11) ◽  
pp. 1828
Author(s):  
Л.Т. Денисова ◽  
М.С. Молокеев ◽  
В.М. Денисов ◽  
Е.О. Голубева ◽  
Н.А. Галиахметова
Keyword(s):  
Experimental Data ◽  
Differential Scanning Calorimetry ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Phase Synthesis ◽  
Influence Of Temperature ◽  
X Ray ◽  
Influence Of Temperature On

The compounds Pb10 ‒ xBix(GeO4)2+x(VO4)4-x (x = 0-3) with an aatite structure were first synthesized from the initial oxides of PbO, Bi2O3, GeO2 and V2O5 by solid ‒ phase synthesis with annealing in air in the temperature range of 773-1073 K. Their structure was determined using x-ray diffraction analysis. The influence of temperature on the heat capacity of synthesized compounds was studied using differential scanning calorimetry. Using the experimental data on Cp = f(T), the thermodynamic properties of the compound have been calculated.

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