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293 results on '"Slanina, Tomáš"'

2. Bridging Electrochemistry and Photoelectron Spectroscopy in the Context of Birch Reduction: Detachment Energies and Redox Potentials of Electron, Dielectron, and Benzene Radical Anion in Liquid Ammonia

Author

Nemirovich, Tatiana, Kostal, Vojtech, Copko, Jakub, Schewe, H. Christian, Bohacova, Sona, Martinek, Tomas, Slanina, Tomas, and Jungwirth, Pavel

Subjects
Physics - Chemical Physics, Physics - Computational Physics
Abstract

Birch reduction is a time-proven way to hydrogenate aromatic hydrocarbons (such as benzene), which relies on the reducing power of electrons released from alkali metals into liquid ammonia. We have succeeded to characterize the key intermediates of the Birch reduction process - the solvated electron and dielectron and the benzene radical anion - using cyclic voltammetry and photoelectron spectroscopy, aided by electronic structure calculations. In this way, we not only quantify the electron binding energies of these species, which are decisive for the mechanism of the reaction but also use Birch reduction as a case study to directly connect the two seemingly unrelated experimental techniques., Comment: after revision

Published
2022
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18. Silicon‐ and Germanium‐Functionalized Perylene Diimides: Synthesis, Optoelectronic Properties, and Their Application as Non‐fullerene Acceptors in Organic Solar Cells

Author

Schlemmer, Bettina, primary, Sauermoser, Aileen, additional, Holler, Sarah, additional, Zuccalà, Elena, additional, Ehmann, Birgit, additional, Reinfelds, Matiss, additional, Fischer, Roland C., additional, Amenitsch, Heinz, additional, Marin‐Beloqui, Jose M., additional, Ludvíková, Lucie, additional, Slanina, Tomáš, additional, Haas, Michael, additional, Rath, Thomas, additional, and Trimmel, Gregor, additional

Published
2023
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22. Biogenic Elements and Heavy Metals in Hermann’s Tortoises—Testudo hermanni: Effect on Serum Biochemistry and Oxidative Status Parameters

Author

Kirchner, Róbert, primary, Kirchnerová, Soňa, additional, Tirpák, Filip, additional, Halo, Marko, additional, Slanina, Tomáš, additional, Tokárová, Katarína, additional, Kováčik, Anton, additional, Miškeje, Michal, additional, Komárňanská, Veronika, additional, Greń, Agnieszka, additional, Formicki, Grzegorz, additional, and Massányi, Peter, additional

Published
2023
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23. Bistable Aryl Azopyrazolium Ionic Photoswitches in Water

Author

Gaur, Ankit Kumar, primary, Gupta, Debapriya, additional, Mahadevan, Anjali, additional, Kumar, Pravesh, additional, Kumar, Himanshu, additional, Nampoothiry, Dhanyaj Narayanan, additional, Kaur, Navneet, additional, Thakur, Sandeep Kumar, additional, Singh, Sanjay, additional, Slanina, Tomáš, additional, and Venkataramani, Sugumar, additional

Published
2023
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25. Photochemistry Driven by Excited-State Aromaticity Gain or Antiaromaticity Relief

Author

Yan, Jiajie, Slanina, Tomáš, Bergman, Joakim, Ottosson, Henrik, Yan, Jiajie, Slanina, Tomáš, Bergman, Joakim, and Ottosson, Henrik

Abstract

Gain of aromaticity or relief of antiaromaticity along a reaction path are important factors to consider in mechanism studies. Analysis of such changes along potential energy surfaces has historically focused on reactions in the electronic ground state (S-0), but can also be used for excited states. In the lowest pi pi* states, the electron counts for aromaticity and antiaromaticity follow Baird's rule where 4n pi-electrons indicate aromaticity and 4n+2 pi-electrons antiaromaticity. Yet, there are also cases where Huckel's rule plays a role in the excited state. The electron count reversals of Baird's rule compared to Huckel's rule explain many altered physicochemical properties upon excitation of (hetero)annulene derivatives. Here we illustrate how the gain of excited-state aromaticity (ESA) and relief of excited-state antiaromaticity (ESAA) have an impact on photoreactivity and photostability. Emphasis is placed on recent findings supported by the results of quantum chemical calculations, and photoreactions in a wide variety of areas are covered.

Published
2023
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26. Spin‐Vibronic Coupling Controls the Intersystem Crossing of Iodine‐Substituted BODIPY Triplet Chromophores.

Author

Doležel, Jiří, Poryvai, Anna, Slanina, Tomáš, Filgas, Josef, and Slavíček, Petr

Subjects
VIBRONIC coupling, STAINS & staining (Microscopy), CHROMOPHORES, MOLECULAR orbitals, WAVE functions, PHOTODYNAMIC therapy
Abstract

4,4‐Difluoro‐4‐borata‐3a‐azonia‐4a‐aza‐s‐indacene (BODIPY) dyes are extensively used in various applications of their triplet states, ranging from photoredox catalysis, through triplet sensitization to photodynamic therapy. However, the rational design of BODIPY triplet chromophores by ab initio modelling is limited by their strong interactions of spin, electronic and vibrational dynamics. In particular, spin‐vibronic coupling is often overlooked when estimating intersystem crossing (ISC) rates. In this study, a combined experimental and theoretical approach using spin‐vibronic coupling to correctly describe ISC in BODIPY dyes was developed. For this purpose, seven π‐extended BODIPY derivatives with iodine atoms in different positions were examined. It was found that the heavy‐atom effect of iodine atoms is site specific, causing high triplet yields in only some positions. This site‐specific ISC was explained by El‐Sayed rules, so both the contribution and character of the molecular orbitals involved in the excitation must be considered when predicting the ISC rates. Overall, the rational design of BODIPY triplet chromophores requires using (i) the high‐quality electronic structure theory, including both static and dynamical correlations; and (ii) the two‐component wave function Hamiltonian, and rationalizing; and (iii) ISC based on the character of the molecular orbitals of heavy atoms involved in the excitation, expanding El‐Sayed rules beyond their traditional applications. [ABSTRACT FROM AUTHOR]

Published
2024
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27. Structure–property–function relationships of stabilized and persistent C- and N-based triaryl radicals.

Author

Vasievska, Anna and Slanina, Tomáš

Subjects
*RADICALS (Chemistry), *STRUCTURAL design, *RADICALS
Abstract

Structurally similar C- and N-based triaryl radicals are among the most commonly used structural motifs in stable, open-shell, organic molecules. The application of such species is associated with their stability, properties and structural design. This study summarizes the basic stabilization and persistence principles of C- and N-based triaryl radicals and highlights recent advances in design strategies of radicals tailored for specific applications. [ABSTRACT FROM AUTHOR]

Published
2024
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28. Photocatalytic Generation of Trifluoromethyl Nitrene for Alkene Aziridination.

Author

Baris, Norbert, Dračínský, Martin, Tarábek, Ján, Filgas, Josef, Slavíček, Petr, Ludvíková, Lucie, Boháčová, Soňa, Slanina, Tomáš, Klepetářová, Blanka, and Beier, Petr

Subjects
AZIRIDINATION, ALKENES, MATERIALS science, ARYL group, VISIBLE spectra, BRONSTED acids
Abstract

N‐Trifluoromethylated organics may be applied in drug design, agrochemical synthesis, and materials science, among other areas. Yet, despite recent advances in the synthesis of aliphatic, cyclic and heterocyclic N‐trifluoromethyl compounds, no strategy based on trifluoromethyl nitrene has hitherto been explored. Here we describe the formation of triplet trifluoromethyl nitrene from azidotrifluoromethane, a stable and safe‐to‐use precursor, by visible light photocatalysis. The addition of CF3N to alkenes via biradical intermediates afforded previously unknown aziridines substituted with trifluoromethyl group on the nitrogen atom. The obtained aziridines were converted into either N‐trifluoromethylimidazolines, via formal [3+2] cycloaddition with nitriles, mediated by a Lewis acid, or into N‐trifluoromethylaldimines, via ring opening and aryl group migration mediated by a strong Brønsted acid. Our findings open new opportunities for the development of novel classes of N‐CF3 compounds with possible applications in the life sciences. [ABSTRACT FROM AUTHOR]

Published
2024
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34. Pharmacokinetics of Intramuscularly Administered Thermoresponsive Polymers (Adv. Healthcare Mater. 22/2022)

Author

Groborz, Ondřej, primary, Kolouchová, Kristýna, additional, Pankrác, Jan, additional, Keša, Peter, additional, Kadlec, Jan, additional, Krunclová, Tereza, additional, Pierzynová, Aneta, additional, Šrámek, Jaromír, additional, Hovořáková, Mária, additional, Dalecká, Linda, additional, Pavlíková, Zuzana, additional, Matouš, Petr, additional, Páral, Petr, additional, Loukotová, Lenka, additional, Švec, Pavel, additional, Beneš, Hynek, additional, Štěpánek, Lubomír, additional, Dunlop, David, additional, Melo, Carlos V., additional, Šefc, Luděk, additional, Slanina, Tomáš, additional, Beneš, Jiří, additional, Van Vlierberghe, Sandra, additional, Hoogenboom, Richard, additional, and Hrubý, Martin, additional

Published
2022
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38. Sperm Quality Affected by Naturally Occurring Chemical Elements in Bull Seminal Plasma

Author

Tirpák, Filip, primary, Halo, Marko, additional, Tomka, Marián, additional, Slanina, Tomáš, additional, Tokárová, Katarína, additional, Błaszczyk-Altman, Martyna, additional, Dianová, Lucia, additional, Ivanič, Peter, additional, Kirchner, Róbert, additional, Greń, Agnieszka, additional, Lukáč, Norbert, additional, and Massányi, Peter, additional

Published
2022
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47. Curcumin Attenuates Damage to Rooster Spermatozoa Exposed to Selected Uropathogens.

Author

Tvrdá, Eva, Petrovičová, Michaela, Benko, Filip, Ďuračka, Michal, Galovičová, Lucia, Slanina, Tomáš, and Kačániová, Miroslava

Subjects
SPERMATOZOA, ROOSTERS, SALMONELLA enterica, CURCUMIN, BACTERIAL contamination, SALMONELLA, SEMEN analysis, SEMEN
Abstract

Artificial insemination, as an essential pillar of the modern poultry industry, primarily depends on the quality of semen collected from stud roosters. Since the collection and storage of ejaculates is not a sterile process, antimicrobial agents have become essential supplements to semen extenders. While the use of traditional antibiotics has been challenged because of rising bacterial resistance, natural biomolecules represent an appealing alternative because of their antibacterial and antioxidant properties. As such, this study strived to compare the effects of 50 μmol/L curcumin (CUR) with 31.2 µg/mL kanamycin (KAN) as a conventional antibiotic on rooster sperm quality in the presence of Salmonella enterica, Escherichia coli and Pseudomonas aeruginosa. Changes in sperm structural integrity and functional activity were monitored at 2 and 24 h of culture. Computer-assisted semen analysis revealed significant sperm motility preservation following treatment with KAN, particularly in the case of Salmonella enterica and Pseudomonas aeruginosa (p < 0.001) after 24 h. On the other hand, CUR was more effective in opposing ROS overproduction by all bacteria (p < 0.05), as determined by luminol-based luminometry, and maintained sperm mitochondrial activity (p < 0.001 in the case of Salmonella enterica; p < 0.05 with respect to Escherichia coli and Pseudomonas aeruginosa), as assessed by the fluorometric JC-1 assay. The TUNEL assay revealed that CUR readily preserved the DNA integrity of rooster sperm exposed to Salmonella enterica (p < 0.01) and Escherichia coli (p < 0.001). The bacteriological analysis showed higher efficiency of KAN in preventing the growth of all selected bacterial species (p < 0.0001) as opposed to CUR. In conclusion, CUR provided protection to rooster spermatozoa against alterations caused by uropathogens, most likely through its antioxidant activity. Hence, CUR supplementation to poultry semen extenders in combination with properly selected antibacterial substances may become an interesting strategy in the management of bacterial contamination during semen storage. [ABSTRACT FROM AUTHOR]

Published
2023
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