0000000000803040
AUTHOR
Radek Marek
showing 22 related works from this author
Hexagonal Microparticles from Hierarchical Self-Organization of Chiral Trigonal Pd3L6 Macrotetracycles
2021
Construction of structurally complex architectures using inherently chiral, asymmetric, or multi-heterotopic ligands is a major challenge in metallosupramolecular chemistry. Moreover, the hierarchical self-organization of such complexes is unique. Here, we introduce a water-soluble, facially amphiphilic, amphoteric, chiral, asymmetric, and hetero-tritopic ligand derived from natural bile acid, ursodeoxycholic acid. We show that via the supramolecular transmetalation reaction, using nitrates of Cu(II) or Fe(III), and subsequently Pd(II), a superchiral Pd3L6 complex can be obtained. Even though several possible constitutional isomers of Pd3L6 could be formed, because of the ligand asymmetry a…
Anion Recognition by a Bioactive Diureidodecalin Anionophore: Solid-State, Solution, and Computational Studies
2018
Recent work has identified a bis-(p-nitrophenyl)ureidodecalin anion carrier as a promising candidate for biomedical applications, showing good activity for chloride transport in cells yet almost no cytotoxicity. To underpin further development of this and related compounds, a detailed structural and binding investigation is reported. Crystal structures of the transporter as five solvates confirm the diaxial positioning of urea groups while revealing a degree of conformational flexibility. Structures of complexes with Cl−, Br−, NO3 −, SO4 2− and AcO−, supported by computational studies, show how the binding site can adapt to accommodate these anions. 1H NMR binding studies revealed exception…
NMR Quantification of Tautomeric Populations in Biogenic Purine Bases
2009
Purine bases such as purine, adenine, hypoxanthine, and mercaptopurine are known to exist in several tautomeric forms. Characterization of their tautomeric equilibria is important not only for predicting the regioselectivity of their N-alkylation reactions but also for gaining knowledge of the patterns with which these compounds of significant biological activity form hydrogen bonds with their biological targets. Low-temperature 1H- and 13C-NMR spectroscopy were used to investigate the tautomeric equilibria for purine and some purine derivatives in methanol and N,N-dimethylformamide solutions. The N(7)H and N(9)H tautomeric forms were quantified by integrating the individual 1H NMR signals …
Direct determination of tautomerism in purine derivatives by low-temperature NMR spectroscopy
2004
An investigation of the purine derivatives N,N-dimethyl-N'-(7(9)-H-purin-6-yl)-formamidine, 6-chloropurine and 6-methoxy purine at low temperatures by NMR spectroscopy has been carried out. Low temperature enabled us in two cases to detect the separate NMR signals of N7-H and N9-H tautomers.
Heads or Tails? Sandwich-Type Metallo Complexes of Hexakis(2,3-di-O-methyl)-α-cyclodextrin
2020
Native and synthetically modified cyclodextrins (CDs) are useful building blocks in the construction of large coordination complexes and porous materials with various applications. Sandwich-type co...
Structural studies of homoisoflavonoids: NMR spectroscopy, X-ray diffraction, and theoretical calculations
2010
Abstract In this article we present a detailed structural investigation for five homoisoflavonoids, molecules important from the pharmacological point of view. For studying the electron distribution as well as its influence on the physicochemical properties, NMR spectroscopy, X-ray diffraction, and theoretical calculations have been used. Nuclear magnetic shieldings obtained by using DFT calculations for optimized molecular geometries are correlated with the experimentally determined chemical shifts. The theoretical data are well in agreement with the experimental values. The single crystal X-ray structures of homoisoflavonoid derivatives 1, 3, and 4 have been solved. The molecular geometri…
Heads or Tails? Sandwich-Type Metallocomplexes of Hexakis(2,3-di-O-methyl)-α-cyclodextrin
2020
Native and synthetically modified cyclodextrins (CDs) are useful building blocks in construction of large coordination complexes and porous materials with various applications. Sandwich-type complexes (STCs) are one of the important groups in this area. Usually, coordination of secondary hydroxyls or the “head” portal of native CD molecules to a notional multinuclear ring of metal cations leads to formation of head-to-head STCs. Our study introduces a new CD-ligand, hexakis(2,3-di-O-methyl)-α-cyclodextrin, which enables formation of intriguing head-to-head, but also novel tail-to-tail STCs. Homometallic silver-based head-to-head STCs, AgPF6-STC and AgClO4-STC, were obtained by coordination …
CCDC 1953708: Experimental Crystal Structure Determination
2021
Related Article: Ondřej Jurček, Nonappa, Elina Kalenius, Pia Jurček, Juha M. Linnanto, Rakesh Puttreddy, Hennie Valkenier, Nikolay Houbenov, Michal Babiak, Miroslav Peterek, Anthony P. Davis, Radek Marek, Kari Rissanen|2021|Cell Reports Physical Science|2|100303|doi:10.1016/j.xcrp.2020.100303
CCDC 1818063: Experimental Crystal Structure Determination
2018
Related Article: Ondřej Jurček, Hennie Valkenier, Rakesh Puttreddy, Martin Novák, Hazel A. Sparkes, Radek Marek, Kari Rissanen, Anthony P. Davis|2018|Chem.-Eur.J.|24|8178|doi:10.1002/chem.201800537
CCDC 1899328: Experimental Crystal Structure Determination
2020
Related Article: Ondřej Jurček, Rakesh Puttreddy, Filip Topić, Pia Jurček, Pezhman Zarabadi-Poor, Hendrik V. Schröder, Radek Marek, Kari Rissanen|2020|Cryst.Growth Des.|20|4193|doi:10.1021/acs.cgd.0c00532
CCDC 1817835: Experimental Crystal Structure Determination
2018
Related Article: Ondřej Jurček, Hennie Valkenier, Rakesh Puttreddy, Martin Novák, Hazel A. Sparkes, Radek Marek, Kari Rissanen, Anthony P. Davis|2018|Chem.-Eur.J.|24|8178|doi:10.1002/chem.201800537
CCDC 1817833: Experimental Crystal Structure Determination
2018
Related Article: Ondřej Jurček, Hennie Valkenier, Rakesh Puttreddy, Martin Novák, Hazel A. Sparkes, Radek Marek, Kari Rissanen, Anthony P. Davis|2018|Chem.-Eur.J.|24|8178|doi:10.1002/chem.201800537
CCDC 1817831: Experimental Crystal Structure Determination
2018
Related Article: Ondřej Jurček, Hennie Valkenier, Rakesh Puttreddy, Martin Novák, Hazel A. Sparkes, Radek Marek, Kari Rissanen, Anthony P. Davis|2018|Chem.-Eur.J.|24|8178|doi:10.1002/chem.201800537
CCDC 1817830: Experimental Crystal Structure Determination
2018
Related Article: Ondřej Jurček, Hennie Valkenier, Rakesh Puttreddy, Martin Novák, Hazel A. Sparkes, Radek Marek, Kari Rissanen, Anthony P. Davis|2018|Chem.-Eur.J.|24|8178|doi:10.1002/chem.201800537
CCDC 1959539: Experimental Crystal Structure Determination
2020
Related Article: Ondřej Jurček, Rakesh Puttreddy, Filip Topić, Pia Jurček, Pezhman Zarabadi-Poor, Hendrik V. Schröder, Radek Marek, Kari Rissanen|2020|Cryst.Growth Des.|20|4193|doi:10.1021/acs.cgd.0c00532
CCDC 1899329: Experimental Crystal Structure Determination
2020
Related Article: Ondřej Jurček, Rakesh Puttreddy, Filip Topić, Pia Jurček, Pezhman Zarabadi-Poor, Hendrik V. Schröder, Radek Marek, Kari Rissanen|2020|Cryst.Growth Des.|20|4193|doi:10.1021/acs.cgd.0c00532
CCDC 1817834: Experimental Crystal Structure Determination
2018
Related Article: Ondřej Jurček, Hennie Valkenier, Rakesh Puttreddy, Martin Novák, Hazel A. Sparkes, Radek Marek, Kari Rissanen, Anthony P. Davis|2018|Chem.-Eur.J.|24|8178|doi:10.1002/chem.201800537
CCDC 1899330: Experimental Crystal Structure Determination
2020
Related Article: Ondřej Jurček, Rakesh Puttreddy, Filip Topić, Pia Jurček, Pezhman Zarabadi-Poor, Hendrik V. Schröder, Radek Marek, Kari Rissanen|2020|Cryst.Growth Des.|20|4193|doi:10.1021/acs.cgd.0c00532
CCDC 1899331: Experimental Crystal Structure Determination
2020
Related Article: Ondřej Jurček, Rakesh Puttreddy, Filip Topić, Pia Jurček, Pezhman Zarabadi-Poor, Hendrik V. Schröder, Radek Marek, Kari Rissanen|2020|Cryst.Growth Des.|20|4193|doi:10.1021/acs.cgd.0c00532
CCDC 1817832: Experimental Crystal Structure Determination
2018
Related Article: Ondřej Jurček, Hennie Valkenier, Rakesh Puttreddy, Martin Novák, Hazel A. Sparkes, Radek Marek, Kari Rissanen, Anthony P. Davis|2018|Chem.-Eur.J.|24|8178|doi:10.1002/chem.201800537
CCDC 1586249: Experimental Crystal Structure Determination
2018
Related Article: Ondřej Jurček, Hennie Valkenier, Rakesh Puttreddy, Martin Novák, Hazel A. Sparkes, Radek Marek, Kari Rissanen, Anthony P. Davis|2018|Chem.-Eur.J.|24|8178|doi:10.1002/chem.201800537
CCDC 1586251: Experimental Crystal Structure Determination
2018
Related Article: Ondřej Jurček, Hennie Valkenier, Rakesh Puttreddy, Martin Novák, Hazel A. Sparkes, Radek Marek, Kari Rissanen, Anthony P. Davis|2018|Chem.-Eur.J.|24|8178|doi:10.1002/chem.201800537