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161.
Marcin Rojkiewicz Piotr Ku Maria Ksiek Joachim Kusz 《Acta Crystallographica. Section C, Structural Chemistry》2022,78(1):56-62
Cathinones belong to a group of compounds of great interest in the new psychoactive substances (NPS) market. Constant changes to the chemical structure made by the producers of these compounds require a quick reaction from analytical laboratories in ascertaining their characteristics. In this article, three cathinone derivatives were characterized by X-ray crystallography. The investigated compounds were confirmed as: 1-[1-(4-methylphenyl)-1-oxohexan-2-yl]pyrrolidin-1-ium chloride ( 1 , C17H26NO+·Cl?, the hydrochloride of 4-MPHP), 1-(4-methyl-1-oxo-1-phenylpentan-2-yl)pyrrolidin-1-ium chloride ( 2 ; C16H24NO+·Cl?, the hydrochloride of α-PiHP) and methyl[1-(4-methylphenyl)-1-oxopentan-2-yl]azanium chloride ( 3 ; C13H20NO+·Cl?, the hydrochloride of 4-MPD). All the salts crystallize in a monoclinic space group: 1 and 2 in P21/c, and 3 in P21/n. To the best of our knowledge, this study provides the first detailed and comprehensive crystallographic data on salts 1 – 3 . 相似文献
162.
Prof. Dr. Antoni W. Morawski Dr. Ewelina Kusiak-Nejman Dr. Iwona Pełech Katarzyna Ćmielewska Dr. Daniel Sibera Piotr Staciwa Dr. Agnieszka Wanag Marcin Gano Dr. Ewa Ekiert Dr. Joanna Kapica-Kozar Kordian Witkowski Prof. Dr. Urszula Narkiewicz 《ChemistryOpen》2022,11(4):e202100262
A new approach to hydrogen production from water is described. This simple method is based on carbon dioxide-mediated water decomposition under UV radiation. The water contained dissolved sodium hydroxide, and the solution was saturated with gaseous carbon dioxide. During saturation, the pH decreased from about 11.5 to 7–8. The formed bicarbonate and carbonate ions acted as scavengers for hydroxyl radicals, preventing the recombination of hydroxyl and hydrogen radicals and prioritizing hydrogen gas formation. In the presented method, not yet reported in the literature, hydrogen production is combined with carbon dioxide. For the best system with alkaline water (0.2 m NaOH) saturated with CO2 under UV-C, the hydrogen production amounted to 0.6 μmol h−1 during 24 h of radiation. 相似文献
163.
Xanthophyll astaxanthin, which is commonly used in aquaculture, is one of the most expensive and important industrial pigments. It is responsible for the pink and red color of salmonid meat and shrimp. Due to having the strongest anti-oxidative properties among carotenoids and other health benefits, natural astaxanthin is used in nutraceuticals and cosmetics, and in some countries, occasionally, to fortify foods and beverages. Its use in food technology is limited due to the unknown effects of long-term consumption of synthetic astaxanthin on human health as well as few sources and the high cost of natural astaxanthin. The article characterizes the structure, health-promoting properties, commercial sources and industrial use of astaxanthin. It presents the possibilities and limitations of the use of astaxanthin in food technology, considering its costs and food safety. It also presents the possibilities of stabilizing astaxanthin and improving its bioavailability by means of micro- and nanoencapsulation. 相似文献
164.
Rafa Lewandkw Miosz Grodzicki Piotr Mazur Antoni Ciszewski 《Surface and interface analysis : SIA》2021,53(1):118-124
Al2O3 insulator layers were deposited step by step by the physical vapor deposition (PVD) method onto gallium nitride in the wurtzite form, n‐type and (0001)‐oriented. The substrate surface and the early stages of Al2O3/n‐GaN(0001) interface formation were characterized in situ under ultra‐high vacuum conditions by X‐ray and ultraviolet photoelectron spectroscopy (XPS, UPS). The electron affinity (EA) of the substrate cleaned by annealing was 3.6 eV. Binding energies of the Al 2p (76.0 eV) and the O 1s (532.9 eV) confirmed the creation of the Al2O3 compound in the deposited film for which the EA was 1.6 eV. The Al2O3 film was found to be amorphous with a bandgap of 6.9 eV determined from the O 1s loss feature. As a result, the calculated Al2O3/n‐GaN(0001) valence band offset (VBO) is ?1.3 eV and the corresponding conduction band offset (CBO) 2.2 eV. 相似文献
165.
Paola Zimmermann Crocomo Takahito Kaihara Soki Kawaguchi. Dr. Patrycja Stachelek Prof. Dr. Satoshi Minakata Prof. Dr. Piotr de Silva Prof. Dr. Przemyslaw Data Prof. Dr. Youhei Takeda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(53):13390-13398
Novel electron donor–acceptor–donor (D-A-D) compounds comprising dibenzo[a,j]phenazine as the central acceptor core and two 7-membered diarylamines (iminodibenzyl and iminostilbene) as the donors have been designed and synthesized. Investigation of their physicochemical properties revealed the impact of C2 insertion into well-known carbazole electron donors on the properties of previously reported twisted dibenzo[a,j]phenazine-core D-A-D triads. Slight structural modification caused a drastic change in conformational preference, allowing unique photophysical behavior of dual emission derived from room-temperature phosphorescence and triplet–triplet annihilation. Furthermore, electrochemical analysis suggested sigma-dimer formation and electrochemical polymerization on the electrode. Quantum chemical calculations also rationalized the experimental results. 相似文献
166.
Let R be a finitely generated algebra over a field of characteristic 0 with a locally nilpotent derivation δ ≠ 0. We show that if {ie313-1}, where the invariants {ie313-2} are prime and satisfy a polynomial identity, then {ie313-3}. Furthermore, when R is a domain, the same conclusion holds without the assumption that R is finitely generated. This enables us to obtain a result on skew polynomial rings. These results extend work of Bell and Smoktunowicz on domains with GK dimension in the interval [2, 3). 相似文献
167.
Alina T. Dubis Piotr Stasiewicz Katarzyna Pogorzelec‐Glaser Andrzej Łapiński 《Journal of Physical Organic Chemistry》2015,28(10):652-662
The formation of intramolecular hydrogen bonding by certain N‐substituted 2‐acylpyrroles has been demonstrated by B3LYP/aug‐cc‐pVDZ calculations, the quantum theory of atoms in molecules, and the natural bond orbital method. Total electron energy densities HBCP at the bond critical point of the H?O bond were applied to analyze the strength of these interactions. The relations between quantum theory of atoms in molecules, carbonyl stretching vibrational modes νC = O, and natural bond orbital parameters associated with the formation of the C–H?O interaction have been established. The short contacts were found experimentally in the crystal structure of a new 2‐acylpyrrole derivative 5‐chloro‐2‐oxopentyl‐1‐(5‐chloro‐2‐oxopentyl)pyrrolo‐2‐carboxylate. The influence of 2‐ and N‐substitution of 2‐acylpyrroles on C‐H?O interaction energy is discussed. It was found that the methylene group may act as a proton donor leading to a red‐shift or blue‐shift phenomenon of the νC–H stretching mode. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
168.
Piotr Łyżwa Marian Mikołajczyk 《Phosphorus, sulfur, and silicon and the related elements》2014,189(7-8):1174-1192
AbstractAminophosphonic acids have become important in different fields of chemistry, medicine and agriculture. In this review article, we highlight a new strategy developed in the author's laboratory of asymmetric synthesis of enantiomeric aminophosphonic acid that users chiral sulfinimines as reagents. A key reaction in the synthesis of enantiopure α-, β- and γ-aminophosphonic acids is a highly or fully diastereoselective addition of trivalent phosphorus nucleophiles and α-phosphonate carbanions to enantiopure sulfinimines. The steric course of these addition reactions is rationalized. The usefulness of the sulfinimine methodology is demonstrated by the synthesis of biologically active enantiopure 2-amino-3-phosphonopropanoic acid (AP3), 2-amino-4-phosphonobutanoic acid (AP4) and phosphoemeriamine. 相似文献
169.
Monika Kijewska Adam Kuc Alicja Kluczyk Mateusz Waliczek Aleksandra Man-Kupisinska Jolanta Lukasiewicz Piotr Stefanowicz Zbigniew Szewczuk 《Journal of the American Society for Mass Spectrometry》2014,25(6):966-976
We present new tags based on the derivatives of phenylboronic acid and apply them for the selective detection of sugars and peptide-sugar conjugates in mass spectrometry. We investigated the binding of phenylboronic acid and its quaternary ammonium salt (QAS) derivatives to carbohydrates and peptide-derived Amadori products by HR-MS and MS/MS experiments. The formation of complexes between sugar or sugar-peptide conjugates and synthetic tags was confirmed on the basis of the unique isotopic distribution resulting from the presence of boron atom. Moreover, incorporation of a quaternary ammonium salt dramatically improved the efficiency of ionization in mass spectrometry. It was found that the formation of a complex with phenylboronic acid stabilizes the sugar moiety in glycated peptides, resulting in simplification of the fragmentation pattern of peptide-derived Amadori products. The obtained results suggest that derivatization of phenylboronic acid as QAS is a promising method for sensitive ESI-MS detection of carbohydrates and their conjugates formed by non-enzymatic glycation or glycosylation. Figure
? 相似文献
170.
Electrospray ionization mass spectrometry (MS) has been widely used to detect noncovalent interactions in supramolecular compounds, especially in biological systems. In our work, we present the application of the electrospray ionization MS technique to characterize the metallamacrocycles, known as metallacrowns. This project involves investigations of the aminohydroxamic acids structure and chirality influence on formation of ternary 12‐metallacrown‐4 complexes. For our experiments, we used a series of β‐aminohydroxamic acids and derivatives of histidinehydroxamic acid. A high stability of the studied supramolecular systems in the gas phase was confirmed by MS/MS experiments. We also proposed the fragmentation pathways for the studied compounds. Obtained results reveal that the ternary 12‐metallacrown‐4 formation process is not selective, and ligands of various structures and chiralities can be incorporated into these systems. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献