Search Results - "Raczyńska, Ewa D."

Enhanced Basicity of Push–Pull Nitrogen Bases in the Gas Phase by Raczyńska, Ewa D, Gal, Jean-François, Maria, Pierre-Charles

“…Nitrogen bases containing one or more pushing amino-group(s) directly linked to a pulling cyano, imino, or phosphoimino group, as well as those in which the…”
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Effects of Positive and Negative Ionization on Prototropy in Pyrimidine Bases: An Unusual Case of Isocytosine by Raczyńska, Ewa D, Makowski, Mariusz

“…Intramolecular proton-transfers (prototropic conversions) have been studied for the guanine building block isocytosine (iC), and effects of positive…”
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Nitriles with High Gas-Phase Basicity—Part II Transmission of the Push–Pull Effect through Methylenecyclopropene and Cyclopropenimine Scaffolds Intercalated between Different Electron Donor(s) and the Cyano N-Protonation Site by Raczyńska, Ewa, Gal, Jean-François, Maria, Pierre-Charles, Sakhawat, Ghulam, Fahim, Mohammad, Saeidian, Hamid

“…This work extends our earlier quantum chemical studies on the gas-phase basicity of very strong N-bases to two series of nitriles containing the…”
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Purine tautomeric preferences and bond-length alternation in relation with protonation-deprotonation and alkali metal cationization by Raczyńska, Ewa D., Gal, Jean-François, Maria, Pierre-Charles, Kamińska, Beata, Igielska, Małgorzata, Kurpiewski, Julian, Juras, Weronika

“…Quantum chemical calculations were carried out for deprotonated ( P − ) and protonated purine ( PH + ) and for adducts with one alkali metal cation ( P − M +…”
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Tautomeric Equilibria and Pi Electron Delocalization for Some MonohydroxyarenesQuantum Chemical Studies by Ośmiałowski, Borys, Raczyńska, Ewa D, Krygowski, Tadeusz M

“…Keto−enol tautomeric interconversions and variations of the π-electron distribution were studied for 11 isolated monohydroxyarenes at the…”
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On Analogies in Proton-Transfers for Pyrimidine Bases in the Gas Phase (Apolar Environment)—Cytosine Versus Isocytosine by Raczyńska, Ewa D.

“…Inter- and intra-molecular proton-transfers between functional groups in nucleobases play a principal role in their interactions (pairing) in nucleic acids…”
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Change of the favored routes of EI MS fragmentation when proceeding from N¹, N¹-dimethyl-N²-arylformamidines to 1,1,3,3-tetraalkyl-2-arylguanidines: substituent effects by Raczyńska, Ewa D, Makowski, Mariusz, Gal, Jean-François, Maria, Pierre-Charles

“…Although series of N¹, N¹-dimethyl-N²-arylformamidines and of 1,1,3,3-tetraalkyl-2-arylguanidines are structurally analogous and similar electron-ionization…”
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Application of the Extended HOMED (Harmonic Oscillator Model of Aromaticity) Index to Simple and Tautomeric Five-Membered Heteroaromatic Cycles with C, N, O, P, and S Atoms by Raczyńska, Ewa

“…The geometry-based HOMA (Harmonic Oscillator Model of Aromaticity) descriptor, based on the reference compounds of different delocalizations of n- and…”
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Quantum-Chemical Studies on the Favored and Rare Tautomers of Neutral and Redox Adenine by Raczyńska, Ewa D, Makowski, Mariusz, Zientara-Rytter, Katarzyna, Kolczyńska, Katarzyna, Stępniewski, Tomasz M, Hallmann, Małgorzata

“…All possible twenty-three prototropic tautomers of neutral and redox adenine (nine amine and fourteen imine forms, including geometric isomerism of the exo NH…”
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Symmetry in Acid-Base Chemistry by Raczyńska, Ewa D.

“…Most organic molecules, including natural products, drugs, and toxicants, contain functional groups that display acid-base properties [...]…”
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Exceptionally High Proton and Lithium Cation Gas-Phase Basicity of the Anti-Diabetic Drug Metformin by Raczyńska, Ewa D, Gal, Jean-François, Maria, Pierre-Charles, Michalec, Piotr, Zalewski, Marcin

“…Substituted biguanides are known for their biological effect, and a few of them are used as drugs, the most prominent example being metformin…”
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Quantum-Chemical Search for Keto Tautomers of Azulenols in Vacuo and Aqueous Solution by Raczyńska, Ewa D.

“…Keto-enol prototropic conversions for carbonyl compounds and phenols have been extensively studied, and many interesting review articles and even books…”
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Consequences of proton transfer in guanidine by Raczyńska, Ewa D., Cyrański, Michał K., Gutowski, Maciej, Rak, Janusz, Gal, Jean-François, Maria, Pierre-Charles, Darowska, Małgorzata, Duczmal, Kinga

“…Consequences of proton‐transfer reactions in guanidine in the solid state, solution and gas phase are discussed. Y‐delocalization, resonance and symmetry…”
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Push–Pull Effect on the Gas-Phase Basicity of Nitriles: Transmission of the Resonance Effects by Methylenecyclopropene and Cyclopropenimine π-Systems Substituted by Two Identical Strong Electron Donors by Raczyńska, Ewa D., Gal, Jean-François, Maria, Pierre-Charles, Saeidian, Hamid

“…The gas-phase basicity of nitriles can be enhanced by a push–pull effect. The role of the intercalated scaffold between the pushing group (electron-donor) and…”
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Experimental and Theoretical Evidence of Basic Site Preference in Polyfunctional Superbasic Amidinazine:  N 1,N 1-Dimethyl-N 2-β-(2-pyridylethyl)formamidine by Raczyńska, Ewa D, Darowska, Małgorzata, Da̧bkowska, Iwona, Decouzon, Michèle, Gal, Jean-François, Maria, Pierre-Charles, Poliart, Christine Dubin

“…The gas-phase basicity (GB) of the flexible polyfunctional N 1,N 1-dimethyl-N 2-β-(2-pyridylethyl)formamidine (1) containing two potential basic sites (the…”
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Can Nitriles Be Stronger Bases Than Proton Sponges in the Gas Phase? A Computational Analysis by Raczyńska, Ewa D, Makowski, Mariusz, Maria, Pierre-Charles, Gal, Jean-François

“…DFT calculations have been performed for a series of push–pull nitriles [(R2N) n (XY) i CN, where i = 0, 1, or 2, n = 1, 2, or 3, R2N = H2N, Me2N, or C4H8N,…”
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Drug-like properties and complete physicochemical profile of pyrazine‑2‑amidoxime: A combined multi-experimental and computational studies by Chylewska, Agnieszka, Biedulska, Małgorzata, Głębocka, Angelika, Raczyńska, Ewa D., Makowski, Mariusz

“…Pyrazine‑2‑amidoxime (PAOX) is a prototypical sp2-hybridized amidoxime. Although, we described first time in details PAOX structure in solid state, the profile…”
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Variations of the tautomeric preferences and π-electron delocalization for the neutral and redox forms of purine when proceeding from the gas phase (DFT) to water (PCM) by Raczyńska, Ewa D., Kamińska, Beata

“…Quantum-chemical calculations were performed for all possible nine neutral tautomers of purine and their oxidized and reduced forms in water…”
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FT-IR spectroscopic, AM1 and PM3 computational studies of conformation of natural products: cytisine by GORNICKA, Elzbieta, RACZYNSKA, Ewa D

“…Infrared spectra were recorded for cytisine ( 1) and its model compounds: N-methyl-2-pyridone ( 2) and piperidine ( 3) in solution. Eight solvents of different…”
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Effects of ionization on stability of 1-methylcytosine — DFT and PCM studies by Raczyńska, Ewa D., Michalec, Piotr, Zalewski, Marcin, Sapuła, Mariusz

“…Consequences of ionization were studied by quantum-chemical methods (DFT and PCM) for 1-methylcytosine ( MC )—a model of the nucleobase cytosine ( C )…”
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