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27 results on '"Spólnik, Grzegorz"'

14. Vitamin B12 Enables Consecutive Generation of Acyl and Alkyl Radicals from One Reagent.

Author

Potrząsaj, Aleksandra, Ociepa, Michał, Baka, Oskar, Spólnik, Grzegorz, and Gryko, Dorota

Subjects
ALKYL radicals, VITAMINS, CARBOXYLIC acids, VITAMIN B12, VITAMIN B2
Abstract

Co complex – Cby(OMe)7 ‐ enables consecutive generation of alkyl and acyl radicals from adequately designed carboxylic acids possessing a halogen atom in theirs structures. Mechanistic studies reveal that alkyl corrins forms at much higher rate than the respective acyl derivatives enabling selective reactions with activated olefins. [ABSTRACT FROM AUTHOR]

Published
2020
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16. Characterization of polar organosulfates in secondary organic aerosol from the unsaturated aldehydes 2-E-pentenal, 2-E-hexenal, and 3-Z-hexenal

Author

Shalamzari, Mohammad Safi, Vermeylen, Reinhilde, Blockhuys, Frank, Kleindienst, Tadeusz E, Lewandowski, Michael, Szmigielski, Rafal, Rudzinski, Krzysztof J, Spólnik, Grzegorz, Danikiewicz, Witold, Maenhaut, Willy, and Claeys, Magda

Subjects
Chemistry, ATMOSPHERIC AEROSOLS, IDENTIFICATION, Earth and Environmental Sciences, Physics, ISOPRENE, AMBIENT AEROSOL, PHOTOOXIDATION, MASS, OXIDATION, GREEN LEAF VOLATILES, KINETICS
Abstract

We show in the present study that the unsaturated aldehydes 2-E-pentenal, 2-E-hexenal, and 3-Z-hexenal are biogenic volatile organic compound (BVOC) precursors for polar organosulfates with molecular weights (MWs) 230 and 214, which are also present in ambient fine aerosol from a forested site, i.e., K-puszta, Hungary. These results complement those obtained in a previous study showing that the green leaf aldehyde 3-Z-hexenal serves as a precursor for MW 226 organosulfates. Thus, in addition to isoprene, the green leaf volatiles (GLVs) 2-E-hexenal and 3-Z-hexenal, emitted due to plant stress (mechanical wounding or insect attack), and 2-E-pentenal, a photolysis product of 3-Z-hexenal, should be taken into account for secondary organic aerosol and organosulfate formation. Polar organosulfates are of climatic relevance because of their hydrophilic properties and cloud effects. Extensive use was made of organic mass spectrometry (MS) and detailed interpretation of MS data (i.e., ion trap MS and accurate mass measurements) to elucidate the chemical structures of the MW 230, 214 and 170 organosulfates formed from 2-E-pentenal and indirectly from 2-E-hexenal and 3-Z-hexenal. In addition, quantum chemical calculations were performed to explain the different mass spectral behavior of 2,3-dihydroxypentanoic acid sulfate derivatives, where only the isomer with the sulfate group at C-3 results in the loss of SO3. The MW 214 organosulfates formed from 2-E-pentenal are explained by epoxidation of the double bond in the gas phase and sulfation of the epoxy group with sulfuric acid in the particle phase through the same pathway as that proposed for 3-sulfooxy-2-hydroxy-2-methylpropanoic acid from the isoprene-related alpha,beta-unsaturated aldehyde methacrolein in previous work (Lin et al., 2013). The MW 230 organosulfates formed from 2-E-pentenal are tentatively explained by a novel pathway, which bears features of the latter pathway but introduces an additional hydroxyl group at the C-4 position. Evidence is also presented that the MW 214 positional isomer, 2-sulfooxy-3-hydroxypentanoic acid, is unstable and decarboxylates, giving rise to 1-sulfooxy-2-hydroxybutane, a MW 170 organosulfate. Furthermore, evidence is obtained that lactic acid sulfate is generated from 2-E-pentenal. This chemistry could be important on a regional and local scale where GLV emissions such as from grasses and cereal crops are substantial.

Published
2016

18. Characterization of polar organosulfates in secondary organic aerosol from the unsaturated aldehydes 2-<i>E</i>-pentenal, 2-<i>E</i>-hexenal, and 3-<i>Z</i>-hexenal

Author

Shalamzari, Mohammad Safi, primary, Vermeylen, Reinhilde, additional, Blockhuys, Frank, additional, Kleindienst, Tadeusz E., additional, Lewandowski, Michael, additional, Szmigielski, Rafal, additional, Rudzinski, Krzysztof J., additional, Spólnik, Grzegorz, additional, Danikiewicz, Witold, additional, Maenhaut, Willy, additional, and Claeys, Magda, additional

Published
2016
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20. Radiodegradation of nadolol in the solid state and identification of its radiolysis products by UHPLC–MS method.

Author

Ogrodowczyk, Magdalena, Dettlaff, Katarzyna, Bednarski, Waldemar, Ćwiertnia, Barbara, Stawny, Maciej, Spólnik, Grzegorz, Adamski, Juliusz, and Danikiewicz, Witold

Abstract

Nadolol ((2R*,3S*)-5-{[(2R*)-3-(tert-butylamino)-2-hydroxypropyl]oxy}-1,2,3,4 tetrahydronaphthalene-2,3-diol) in substantia was exposed to ionizing radiation generated by a beam of high-energy electrons in an accelerator, in the standard sterilisation dose of 25 kGy and in higher doses of 50 − 400 kGy. The irradiated and non-irradiated (control) samples were analysed by the infrared spectrophotometry, electron paramagnetic resonance, differential scanning calorimetry (DSC) and ultra-high performance liquid chromatography coupled with mass spectrometry (UHPLC–MS). The irradiated samples were found to contain free radicals in concentrations much higher than that observed for the other irradiated β-blockers. On the basis of UHPLC–MS results, it was possible to establish structures of 11 compounds of the impurities and/or products of nadolol decomposition. The main product of radiodegradation was concluded to be formed as a result of abstraction of the hydroxyl group and aromatization of the tetrahydronaphthalene ring. The results of DSC measurements confirmed the presence of radiolysis products in the irradiated samples of nadolol. A shift of the endothermic peak corresponding to melting towards lower temperatures (by 4.4 °C at the dose of 400 kGy) was directly proportional to the doses of radiation used, which permits concluding that this method is sensitive and suitable for evaluation of radiodegradation of nadolol in solid phase. [ABSTRACT FROM AUTHOR]

Published
2018
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22. Ruthenium–Amido Complexes: Synthesis, Structure, and Catalytic Activity in Olefin Metathesis

Author

Pietraszuk, Cezary, primary, Rogalski, Szymon, additional, Powała, Beata, additional, Miętkiewski, Miłosz, additional, Kubicki, Maciej, additional, Spólnik, Grzegorz, additional, Danikiewicz, Witold, additional, Woźniak, Krzysztof, additional, Pazio, Aleksandra, additional, Szadkowska, Anna, additional, Kozłowska, Anna, additional, and Grela, Karol, additional

Published
2012
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23. Synthesis, Structure, and Explosive Properties of a New Trinitrate Derivative of an Unexpected Condensation Product of Nitromethane with Glyoxal

Author

Cudziło, Stanisław, primary, Nita, Marcin, additional, Chołuj, Artur, additional, Szala, Mateusz, additional, Danikiewicz, Witod, additional, Spólnik, Grzegorz, additional, Krompiec, Stanisław, additional, Michalik, Sławomir, additional, Krompiec, Michał, additional, and Świtlicka, Anna, additional

Published
2012
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26. Efficient Functionalisation of Cubic Monovinylsilsesquioxanes viaCrossMetathesis and Silylative Coupling with Olefins in the Presence of Ruthenium Complexes

Author

ak, Patrycja, Pietraszuk, Cezary, Marciniec, Bogdan, Spólnik, Grzegorz, and Danikiewicz, Witold

Abstract

Monovinylheptaisobutylsilsesquioxane undergoes efficient crossmetathesis and silylative coupling with styrenes. Allyl derivatives were successfully tested in crossmetathesis in the presence of first generation Grubbs’ catalyst, while heteroatomsubstituted vinyl derivatives vinyl ethers, 9vinylcarbazole efficiently undergo silylative coupling catalysed by ruthenium hydride complexes. Both reactions proceed highly stereoselectively and lead to nearly quantitative formation of Eisomers. Only when vinyl ethers are used does the reaction lead to a mixture of stereoisomers. Atmospheric pressure photoionisation has been successfully used for recording mass spectra of the functionalised silsesquioxanes.

Published
2009
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