OPEN Repository

Welcome to OPEN - the Repository of Open Scientific Publications, run by the Interdisciplinary Centre for Mathematical and Computational Modelling, University of Warsaw, previously operating as the CeON Repository. The Repository enables Polish researchers from all fields to openly share their articles, books, conference materials, reports, doctoral theses, and other scientific texts.

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22799 archived items

Recent Submissions

Influence of heterochirality on the structure, dynamics, biological properties of cyclic(PFPF) tetrapeptides obtained by solvent‑free ball mill mechanosynthesis
(Nature Portfolio, 2024) Bak‑Sypien, Irena; Pawlak, Tomasz; Paluch, Piotr; Wroblewska, Aneta; Dolot, Rafał; Pawlowicz, Aleksandra; Szczesio, Małgorzata; Wielgus, Ewelina; Kaźmierski, Sławomir; Górecki, Marcin; Pawlowska, Roza; Chworos, Arkadiusz; Potrzebowski, Marek J.; Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences; Institute of Bioorganic Chemistry, Polish Academy of Sciences; Institute of General and Ecological Chemistry, Faculty of Chemistry, Łódź University of Technology; Institute of Organic Chemistry, Polish Academy of Sciences
Cyclic tetrapeptides c(Pro-Phe-Pro-Phe) obtained by the mechanosynthetic method using a ball mill were isolated in a pure stereochemical form as a homochiral system (all L-amino acids, sample A) and as a heterochiral system with D configuration at one of the stereogenic centers of Phe (sample B). The structure and stereochemistry of both samples were determined by X-ray diffraction studies of single crystals. In DMSO and acetonitrile, sample A exists as an equimolar mixture of two conformers, while only one is monitored for sample B. The conformational space and energetic preferences for possible conformers were calculated using DFT methods. The distinctly different conformational flexibility of the two samples was experimentally proven by Variable Temperature (VT) and 2D EXSY NMR measurements. Both samples were docked to histone deacetylase HDAC8. Cytotoxic studies proved that none of the tested cyclic peptide is toxic.
Strongly Polarized π-Extended 1,4-Dihydropyrrolo[3,2-b]pyrroles Fused with Tetrazolo[1,5-a]quinolines
(ACS Publications, 2024) Teimouri, Mohammad B.; Deperasińska, Irena; Rammo, Matt; Banasiewicz, Marzena; Stark, Charles W.; Dobrzycki, Łukasz; Cyrański, Michał K.; Rebane, Aleksander; Gryko, Daniel T.; Institute of Organic Chemistry, Polish Academy of Sciences; Institute of Physics, Polish Academy of Sciences; Faculty of Chemistry, Kharazmi University, Tehran, Iran; National Institute for Chemical Physics and Biophysics, Tallinn, Estonia; Faculty of Chemistry, University of Warsaw; Department of Physics, Montana State University, Montana, United States
A straightforward route to 1,4-dihydropyrrolo[3,2-b]pyrroles comprised of two electron-withdrawing quinoline or tetrazolo[1,5-a]quinoline scaffolds has been developed. The versatile multicomponent reaction affording 1,4-dihydropyrrolo[3,2-b]pyrroles combined with intramolecular direct arylation enables assembly of these products in just three steps from anilines with overall yields exceeding 30%. The planarized, ladder-type heteroacenes possess up to 14 conjugated rings. These nominally quadrupolar materials exhibit efficient fluorescence with wavelengths spanning most of the visible spectrum from green−yellow for the dyes possessing biaryl bridges and orange−red for the fully fused systems. In many cases, the fluorescence quantum yields are large, the solvatofluorochromic effects are strong, and the fluorescence is maintained even in crystalline state. Analysis of the electronic structure of these molecular architectures using quantum chemical methods suggests that the character and position of the flanking heterocycle determine the shape of HOMO and LUMO and their extension to N-aryl substituents, influencing the values of molar absorption coefficient. An experimental study of the two-photon absorption (2PA) properties has revealed that it occurs in the 700−800 nm range with apparent deviation from the Laporte parity selection rule, which may be attributed to Hertzberg−Teller contribution to vibronically allowed 2PA transition.
Access to 2‑Alkenyl-furans via a Cascade of Pd-Catalyzed Cyclization / Coupling Followed by Oxidative Aromatization with DDQ
(ACS Publications, 2024) Bisek, Bartosz; Chaładaj, Wojciech; Institute of Organic Chemistry, Polish Academy of Sciences
An unprecedented DDQ-mediated oxidative aromatization of 2-bezylidene-dihydrofurans yielding 2-alkenyl-furans is disclosed. Integration of this transformation with a prior Pd-catalyzed reaction of α-propargylic-β-ketoesters and (hetero)aryl halides into a one-pot cascade process opens a direct modular route to highly substituted 2-vinyl-furans. Experimental and computational studies reveal that the crucial step of the oxidative-aromatization involves facile hydride transfer from the dihydrofuran ring to the O-center of DDQ.
The Influence of Ligands on the Pd-Catalyzed Diarylation of Vinyl Esters
(MDPI, 2024) Brodzka, Anna; Koszelewski, Dominik; Trzeciak, Anna; Ruzik, Lena; Grela, Malgorzata; Ostaszewski, Ryszard; Institute of Organic Chemistry, Polish Academy of Sciences; Faculty of Chemistry, University of Wrocław; Faculty of Chemistry, Warsaw University of Technology
The impact of ligands on the palladium-catalyzed 1,2-diarylation reaction course is presented. The application of Pd-dmpzc as a catalyst provides an efficient, chemoselective and sustainable protocol for the synthesis of valuable 1,2-diphenylethyl acetates. The reaction is conducted in water under mild conditions. Reaction products can be easily separated from the reaction mixture and catalyst by simple extraction. What is more, the rational choice of catalyst significantly reduces the leaching of the metal into the product and its contamination (0.1 ppm). Efficient phase separation and ultralow Pd leaching enable the reuse of the water medium containing the Pd-dmpzc catalyst several times without a significant loss of activity and with even higher selectivity (from 95% to 100% in the third cycle). The recyclability of both the catalyst and the reaction medium together with high chemoselectivity and low palladium leaching reduces the amount of waste and the cost of the process, exhibiting an example of a sustainable and green methodology.
Remote control of anion binding by CH-based receptors
(Royal Society of Chemistry, 2024) Jurek, Paulina; Szymański, Marek P.; Szumna, Agnieszka; Institute of Organic Chemistry, Polish Academy of Sciences
We show that the substitution of tetra(benzimidazole)resorcin-[4]arenes with electron withdrawing groups on the upper rim enhances anion binding at the opposite edge by more than three orders of magnitude. Moreover, selective anion binding at either the OH/NH or CH binding sites is emonstrated.