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17O NMR study of LnIIIcomplexes of H4do3apOEt ligand
Svítok, Adam ; Hermann, Petr (advisor) ; Dračínský, Martin (referee)
Macrocyclic complexes of H4dota-like ligands are used in various fields, mainly in medicine. e. g. as MRI contrast agents or luminescent probes. Their applications are greatly influenced by stereochemistry. Stereoisomers of these complexes mostly interconvert with each other in solution. This interconversion can be studied by NMR spectroscopy This work is intended to test 17 O NMR spectroscopy as a tool for monitoring dynamic processes where phosphonate group in the complexes of methylphosphonate derivatives of H4dota is involved. To this end, ligand H4do3apOEt and his LnIII -complexes (Ln ≠ Pm) containing 17 O-labeled phosphonate group were synthesized. Next, 17 O NMR spectra of these complexes were measured and analysed. In an analogy with H4dota complexes, signals of both non-coordinated and coordinated oxygen atoms (except GdIII ) in the complexes could be detected. Fraction of TSA (twisted square-antiprism) and SA (square-antiprism) isomers was determined from the acquired 17 O NMR spectrum for each complex. The determined values were compared with those obtained by analysing 1 H and 31 P NMR spectra of the complexes, which were also measured. The TbIII , DyIII and YbIII complexes (because of high resolution of their 17 O NMR spectra) and CeIII complex (because of anomalous properties of its...
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Coordination Compounds as Contrast Agents for 19F-MRI
Špánek, Jiří ; Kotek, Jan (advisor) ; Vojtíšek, Pavel (referee)
Magnetic Resonance Imaging (MRI) is one of noninvasive imaging and diagnostic methods in today's medicine. The most commonly measured nucleus is H1 of the water molecules present in the human body. There are also methods that use signal saturation transfer between the contrast agent and water molecules via exchangeable H1 nuclei, or use a different nucleus like F19 . Compounds that show a high potential in this area are complexes of paramagnetic ions such as Gd3+ , Eu3+ , Co2+ , Cu2+ and Ni2+ , which can affect relaxation times and chemical shifts of other atoms due to their magnetic properties. This Master's thesis focuses on ligands L1 and L2 which were prepared in the Bachelor thesis. The main focus is on preparation of complexes with selected paramagnetic ions and subsequent study of their properties relevant for a potential use as contrast agents for F19 -MRI and CEST methods. Keywords: F19 -MRI, CEST, macrocyclic ligands, coordination chemistry
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Prion Diseases - a role of transition metal ions
Malová, Zuzana ; Lukeš, Ivan (advisor) ; Moško, Tibor (referee)
Prion diseases are widely spread diseases among mammalians. They are characterized by a change of prion protein structure PrPC (cellular, native state) to PrPSc (scrapie, structure typical for prion diseases). It is a change at secondary structure of protein from α-helical to β-sheet structure, which aggregates in brain. One possibility, why it happens is higher transitional metal ions concentration (Zn(II), Cu(II), Fe(III)) in the brain, which bind to PrPC and affects its structure. Aim of this thesis is a synthesis one of protentional drugs based on 2-aminothiazole and its modification to bind fluorescent or radiochemical markers and in future study of its possible interaction with transition metal ions. Key words: complexes; macrocyclic ligands; copper; prion diseases
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Contrast agents for hereronuclear MRI
Koucký, Filip ; Kotek, Jan (advisor) ; Havlík, Jan (referee)
In this thesis the pH dependency of the coordination modes of lanthanide complexes with macrocyclic ligands based on 1,4,7,10-tetraazacyclododecane skeleton was studied. The cyclen-based ligand structures in this work contained three acetate and one aminoethyl group with a N-alkyl-N-methylphosphonate substituent, DO3AN(R)P, where R is an alkyle substituent on the nitrogen atom of the pendant arm (R = methyl, benzyl). Lanthanide complexes of a previously studied prototype ligand DO3ANP with secondary amino group (R = H) have shown interesting properties in the field of 31 P NMR imaging because of their various coordination properties, which allow in situ pH measurement. These complexes can also be used for monitoring the kinetics of the chemical exchange of the amino group proton in 1 H NMR imaging using the chemical exchange saturation transfer (CEST NMR). In this thesis, two new derivatives DO3ANMeP and DO3ANBnP were prepared in order to better understand the coordination modes changes in this ligand series. Also, their coordination behaviour with selected lanthanide ions was studied (Eu3+ , Gd3+ , Dy3+ , Yb3+ ). Based on a series of NMR and luminescence measurements, it was found out, that in acidic conditions the complexes containing DO3ANP motif bind a water molecule in their coordination...
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Ligand design for medicinal applications
Paúrová, Monika ; Kotek, Jan (advisor) ; Trávníček, Zdeněk (referee) ; Řezanka, Pavel (referee)
In recent years, copper radioisotopes have been extensively studied for their suitable coordination and physical properties. Nuclides 61 Cu, 64 Cu and 67 Cu are used in nuclear medicine - in diagnostic as well as in therapeutic applications. The aim of the Thesis is a study of the coordination properties of divalent copper as a stepping stone for the next potential applications. The presented Thesis consists of two thematic parts. The first part deals with the synthesis of cyclam derivatives. Sixteen new macrocyclic ligands with different phosphorus acid coordinating pendant arms (phosphinate, phosphonate, germinal P-C-P) were prepared; an analogous ligand endowed by carboxylic acid pendant arm as well as tetramethylcyclam without coordinating arm were prepared for comparison. The influence of the nature of coordinating acid pendant arms on selectivity and on the rate of copper(II) complexation was studied in detail. The protonation constants of the free ligands and the stability constants of the complexes with selected transition metal ions were determined by potentiometric titrations and by 1 H and 31 P NMR spectroscopy. Kinetic properties - i.e. studies of the formation rate and kinetic inertness of the copper(II) complexes - were performed by UV-Vis spectroscopy. The formation kinetics of the selected...
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Coordination properties of TACN ethylphosphonic derivative
Poláková, Zuzana ; Kubíček, Vojtěch (advisor) ; Schulz, Jiří (referee)
Ligand NOTPOEt was synthesized. Protonation constants and stability constants of Cu(II), Zn(II), Ni(II) and Ga(III) complexes were determined by potentiometric titrations. Cu(II) complex was characterized by UV-VIS spectroscopy and formation of Ga(III) complex was studied by NMR spectroscopy. The work was aimed at characterisation of the ligand with respect to potential application in biomedical imaging techniques.
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MRI contrast agents for angiography
Urbanovský, Peter ; Kotek, Jan (advisor) ; Vojtíšek, Pavel (referee)
Modern diagnostic method magnetic resonance imaging (MRI) usually uses contrast agents T1-type, which are based on Gd3+ complexes. Due to severe toxicity of free Gd3+ , it is desired to have thermodynamically stable and kinetically inert complexes with fast elimination from the body. This work summarizes information about a novel contrast agent based on ligand DO3AP (1,4,7,10-tetraazacyclododecane-1-methyl(alkyl)phosphinic-4,7,10- triacetic acid) with pendant hydrophobic dibenzylamino group which is able to interact hydrophobically with the macromolecule of serum albumin. The stability of supracomplex is dependent on pH value, i.e. on the protonation of the pendant amino group of the complex (pKA = 5.6) and this interaction was confirmed from 1 H-NMRD profile and fluorescent analysis. The compound was tested for its angiographic properties in vivo on rat model. Furthermore, other complexes of the ligand with trivalent lanthanides (Nd3+ , Eu3+ , Tb3+ , Dy3+ , Er3+ ) were characterized by various methods (XRD, luminescence, UV-VIS, 1 H-, 17 O- and 31 P-NMR). The cleavage of the benzyl groups affords ligand whose Ln3+ complexes possess pH dependent PARACEST effect. These complexes were characterized by XRD, luminescence and 1 H- and 31 P-NMR. Moreover, the novel ligands with modified length of pendant...
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New ligands for magnetic resonance imaging - pH-resposive contrast agents
Urbanovský, Peter ; Kotek, Jan (advisor) ; Vojtíšek, Pavel (referee)
Fast spread of MRI technique has brought new demands for MRI contrast agents. They are required to be nontoxic, kinetically inert, thermodynamically stable, biologically inactive complexes Gd(III) with high relaxivity (the ability of magnetic compounds to increase the relaxation rates of the surrounding water proton spins), removable from body in unchanged form. This bachelor thesis resumes basic theory for contrast agents, synthesis of new ligand and its Gd(III) complex coordinating one molecule of water and with ability of the non-covalent interaction of benzylic group with serum albumine resulting in increase in relaxivity. Luminiscence were measured for Eu(III) and Tb(III) complexes and relaxivity of Gd(III) complex in and without the presence of bovine serum albumine in vitro. The novel contrast agent was tested in vivo on rat model. Keywords MRI, gadolinium, macrocyclic ligands, macrocyclic complexes
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The design and synthesis of selective copper(II) chelators
Havlík, Jan ; Kotek, Jan (advisor) ; Holzhauser, Petr (referee)
Title: Design and synthesis of selective copper(II) chelators Author: Jan Havlík Department: Department of Inorganic Chemistry, Faculty of Science Supervisor: assoc. prof. RNDr. Jan Kotek, Ph.D. Supervisor's e-mail address: modrej@natur.cuni.cz The aim of this work was to prepare selective copper(II) chelators. Within the frame of this thesis were synthesized 13 compounds, from which 7 are new. All compounds were fully characterized by NMR spectroscopy and mass spectrometry. Copper(II) complex of synthesized ligand 1,11-bis(methylphosphinic acid)cyclam, (1,11-dipin), was studied in thermodynamic and formation/decomplexation studies. For 1,11-dipin-copper(II) complex were determined values of rate constants and activation parameters. Keywords: selective chelator, copper, cyclam derivatives, macrocyclic ligands, methylphosphonate, methylphosphinate
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