scholarly journals Особенности электролюминесценции алюминия и его нанопористого оксида в сложных эфирах и кетонах

2021 ◽  
Vol 129 (7) ◽  
pp. 938
Author(s):  
Д.С. Oвеченко ◽  
А.П. Бойченко ◽  
Н.А. Яковенко
Keyword(s):  
Dibutyl Phthalate ◽  
Pure Aluminum ◽  
Diethyl Malonate ◽  
Dicarboxylic Acids ◽  
Nanoporous Structure ◽  
Diethyl Oxalate ◽  
Initial Structure ◽  
Carbonyl Groups ◽  
Ir And Nmr Spectroscopy ◽  
Related Compounds

On the example of esters of carboxylic and dicarboxylic acids (ethyl acetate, diethyl oxalate, diethyl malonate, diethyl phthalate and dibutyl phthalate), as well as ketones, lactams and diketones (acetone, cyclohexanone, 4-ethylpropiophenone, acetylacetone and methylpyrrolidone) studies were carried out to generate electroluminescence (EL) in them of pure aluminum (Al) and preoxidized (Al2O3) in distilled water. The absence of EL in pure Al in ethers was revealed, and the regularities of luminescence generation in them for the oxidized metal were established. It was shown that in ketones and related compounds - lactams and diketones, the appearance of EL is possible for both states of the Al anode. In this case, the EL spectra have broad bands in the range 400 - 700 nm with maxima characteristic of the carboxyl and carbonyl groups of the electrolytes used, as well as the nanoporous structure of the formed Al2O3 and carbon-containing impurities captured by it during the growth. In some ethers and ketones, the effect of transformation of the initial structure of the oxide, as well as an increase in its thickness, was found. The absence of any changes in the chemical composition of electrolytes after anodic oxidation of Al in them or transformation of Al2O3 was established by UV, IR and NMR spectroscopy.

Transformation of the Nanoporous Structure of Anodic Aluminium Oxide and its “Nonelectrolysis” Electroluminescence

2020 ◽  
Vol 312 ◽  
pp. 166-171
Author(s):  
Dmitry Ovechenko ◽  
Alexander Boychenko
Keyword(s):  
Structural Organization ◽  
Pure Aluminum ◽  
Nanoporous Structure ◽  
Geometrical Parameters ◽  
Carbonyl Groups ◽  
Lower Intensity ◽  
External Voltage ◽  
Electrolytic Oxidation ◽  
Related Compounds ◽  
Electrolysis Products

On a film of aluminum oxide (Al2O3) formed by electrolytic oxidation in distilled water (DW), the growth, transformation of its nanoporous structure, and the generation of electroluminescence (EL) in ketones and related compounds containing carbonyl groups were studied. For those contributing to the brightest EL – acetylacetone and methylpyrrolidone, it was found that the processes described in these electrolytes proceed with the highest intensity. Under the same electrolytes and conditions, similar processes, but with a lower intensity, proceed for A2O3 formed on pure aluminum. It was found that, with the external voltage, thermodynamic and geometrical parameters of the electrolytic system being constant, the brightness characteristics of the EL of the anodic Al2O3 are influenced by its structural organization and the electrophysical characteristics of the electrolyte surrounding the oxide film, which is proposed to be arbitrarily called “nonelectrolysis” because electrolysis products are not revealed in it.

scholarly journals New Substrates for the Dicarboxylate Transport System of Sinorhizobium meliloti

2000 ◽  
Vol 182 (15) ◽  
pp. 4216-4221 ◽  
Author(s):  
Svetlana Yurgel ◽  
Michael W. Mortimer ◽  
Kimberly N. Rogers ◽  
Michael L. Kahn
Keyword(s):  
Dicarboxylic Acid ◽  
Transport System ◽  
Sinorhizobium Meliloti ◽  
Monocarboxylic Acid ◽  
Dicarboxylic Acids ◽  
Carbonyl Groups ◽  
Nitrogen Fixing ◽  
Extended Conformation ◽  
Dicarboxylate Transport ◽  
Succinamic Acid

ABSTRACT The dicarboxylate transport (Dct) system of Sinorhizobium meliloti, which is essential for a functional nitrogen-fixing symbiosis, has been thought to transport only dicarboxylic acids. We show here that the permease component of the Dct system, DctA, can transport orotate, a monocarboxylic acid, with an apparentKm of 1.7 mM and a V maxof 163 nmol min−1 per mg of protein in induced cells. DctA was not induced by the presence of orotate. The transport of orotate was inhibited by several compounds, including succinamic acid and succinamide, which are not dicarboxylic acids. The dicarboxylic acid maleate (cis-butenedioic acid) was not an inhibitor of orotate transport, which suggests that it was not recognized by DctA. However, maleate was an excellent inducer of DctA expression. Our evaluation of 17 compounds as inducers and inhibitors of transport suggests that substrates recognized by S. meliloti DctA must have appropriately spaced carbonyl groups and an extended conformation, while good inducers are more likely to have a curved conformation.

1,2-Bis(1-aryl-3-alkyltriazen-3-yl)ethanes and related compounds

1998 ◽  
Vol 76 (1) ◽  
pp. 125-135 ◽  
Author(s):  
Donald L Hooper ◽  
Ian R Pottie ◽  
Marc Vacheresse ◽  
Keith Vaughan
Keyword(s):  
Nmr Spectroscopy ◽  
Line Broadening ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Ir And Nmr Spectroscopy ◽  
Diazonium Coupling ◽  
Significant Line ◽  
Related Compounds ◽  
C Nmr

A series of novel bistriazenes, the 1,2-bis(1-aryl-3-methyltriazen-3-yl)ethanes, Ar-N T N-NMe-CH2CH2-NMe-N T N-Ar, have been synthesized by diazonium coupling with N,N'-dimethylethylenediamine. These bistriazenes are stable crystalline compounds and have been unequivocally characterized by IR and NMR spectroscopy (1H and 13C), and elemental analysis. The structures of two compounds in the series have been confirmed by X-ray crystallography. The 1H NMR spectra show significant line broadening of the N-methyl resonances arising from the restricted rotation around the N2-N3 bond of the triazene units. The presence of strongly electron-withdrawing groups on the aryl ring restricts the rotation to the point where the N-methyl signals of the rotamers are distinct even at room temperature; four resonances of the N-methyl signal are clearly evident and these can be assigned to the anti-anti, syn-syn, and syn-anti conformations of the bistriazene. Diazonium coupling with N,N'-diethylethylenediamine affords the N,N'-diethyl homologues of the bistriazenes, which have been similarly characterized. As model compounds to assist in spectroscopic analysis, a series of related triazenes, the 1-(1-aryl-3-methyltriazen-3-yl)-N,N-dimethyl-2-ethanamines, were prepared by diazonium coupling with N,N,N'-trimethylethylenediamine. These dialkyltriazenes exist mainly as oils, but characterization was achieved by IR, 1H NMR, and 13C NMR spectroscopy, also showing the presence of two rotamers in solution when strongly electron-withdrawing substituents are bonded to the aryl moiety.Key words: triazene, bistriazene, diazonium, ethylenediamine, molecular dynamics, NMR.

scholarly journals Molecular distributions of dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in biomass burning aerosols: implications for photochemical production and degradation in smoke layers

2010 ◽  
Vol 10 (5) ◽  
pp. 2209-2225 ◽  
Author(s):  
S. Kundu ◽  
K. Kawamura ◽  
T. W. Andreae ◽  
A. Hoffer ◽  
M. O. Andreae
Keyword(s):  
Mass Spectrometry ◽  
Oxalic Acid ◽  
Biomass Burning ◽  
Large Scale ◽  
Dicarboxylic Acids ◽  
Size Class ◽  
The Other ◽  
Polluted Environment ◽  
Photochemical Production ◽  
Related Compounds

Abstract. Aerosols in the size class <2.5 μm (6 daytime and 9 nighttime samples) were collected at a pasture site in Rondônia, Brazil, during the intensive biomass burning period of 16–26 September 2002 as part of the Large-Scale Biosphere-Atmosphere Experiment in Amazonia – Smoke, Aerosols, Clouds, Rainfall and Climate (LBA-SMOCC). Homologous series of dicarboxylic acids (C2–C11) and related compounds (ketocarboxylic acids and α-dicarbonyls) were identified using gas chromatography (GC) and GC/mass spectrometry (GC/MS). Among the species detected, oxalic acid was found to be the most abundant, followed by succinic, malonic and glyoxylic acids. Average concentrations of total dicarboxylic acids, ketocarboxylic acids and α-dicarbonyls in the aerosol samples were 2180, 167 and 56 ng m−3, respectively. These are 2–8, 3–11 and 2–16 times higher, respectively, than those reported in urban aerosols, such as in 14 Chinese megacities. Higher ratios of dicarboxylic acids and related compounds to biomass burning tracers (levoglucosan and K+) were found in the daytime than in the nighttime, suggesting the importance of photochemical production. On the other hand, higher ratios of oxalic acid to other dicarboxylic acids and related compounds normalized to biomass burning tracers (levoglucosan and K+) in the daytime provide evidence for the possible degradation of dicarboxylic acids (≥C3) in this smoke-polluted environment. Assuming that these and related compounds are photo-chemically oxidized to oxalic acid in the daytime, and given their linear relationship, they could account for, on average, 77% of the formation of oxalic acid. The remaining portion of oxalic acid may have been directly emitted from biomass burning as suggested by a good correlation with the biomass burning tracers (K+, CO and ECa) and organic carbon (OC). However, photochemical production from other precursors could not be excluded.

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