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Complexes of 1,4,7-triazacyclononane phosphinate derivatives
Lebruška, Viktor ; Kubíček, Vojtěch (advisor) ; Štěpnička, Petr (referee)
Phosphorus pendant arms accelerate the complexation of gallium(III) ions with macrocyclic chelators, which is crucial parameter in labelling by the radioisotope 68 Ga and their use in positron emission tomography (PET). In this thesis, new chelators for the selective complexation of gallium(III) ions were designed. Two chelators derived from the TACN macrocycle were prepared, namely: 1,4,7-triazacyclononane-1-methyl-methylene- bis(phosphinic) acid (H2L1 ) and 1,4,7-triazacyclononane-1-methyl-methylene- bis(phosphinato)-4,7-bis(methyl-phosphinic) (H4L2 ). The acidobase properties of the H2L1 were investigated using potentiometric and NMR titrations. Complexes of H2L1 with Ni(II), Cu(II), Zn(II) and Ga(III) were investigated using potentiometric titrations, which showed the high stability of these complexes. The solid-state structures of the Cu-L1 and Zn-L1 complexes were determined by X-ray diffraction. Complexation of the radioisotope 68 Ga(III) was studied for chelators H2L1 , H4L2 and for several related chelators with phosphorus pendant arms. The complexation study showed that chelators with the methylene-bis(phosphinate) pendant arm and some other phosphorus chelators derived from the TACN macrocycle accelerate complexation of gallium(III) ions. Using Dynamic PET scanning and ex-vivo...
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Dimer macrocyclic complexes
Rys, Jan ; Kubíček, Vojtěch (advisor) ; Vojtíšek, Pavel (referee)
This thesis is focused on dimer macrocyclic ligands and their complexes. Two dimer macrocyclic ligands based on ligand DO3A, linked with xylyl linker were prepared (BDO3A-p-X a BDO3A-m-X). Both synthetized ligands were characterized using NMR, MS, EA and in the case of BDO3A-p-X by X-ray crystallography. Data for calculating pseudo-first order reaction rates for complexations with Ce3+ metal ion and their pH dependency were obtained by use of UV/VIS spectrophotometry. Obtained data were compared to structurally close monomer ligand BnDO3A. Dimer ligands display different coordination properties based on proximity and position of coordinating cavities. Both prepared ligands behave differently than structurally close monomer ligand BnDO3A.
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Complexes of polydentate ligands
Sedláčková, Simona ; Kubíček, Vojtěch (advisor) ; Kotek, Jan (referee)
Polydentate ligands are useful in many industries, mainly because of their ability to form complexes. The aim of this thesis is to study acid-base and coordination properties of polydentate ligands from the group of polyaminopolyphosphonates DTPMP and HMDTMP. The protonation constants of ligands as well as stability constants of complexes with biologically relevant ions Cu2+ , Zn2+ , Ni2+ , Mg2+ , Ca2+ , Co2+ , K+ and Na+ were determined by potentiometric titration. 31 P-NMR titration was used to determine pKa on nitrogen atoms, which could not be measured by potenciometric titration. Seven pKa for HMDTMP ligand and nine for DTPMP were obtained. The stability constants show that the HMDTMP ligand forms less stable complexes than the DTPMP ligand.
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Complexes of 1,4,7-triazacyclonane for nuclear medicine
Lebruška, Viktor ; Kubíček, Vojtěch (advisor) ; Schulz, Jiří (referee)
The use of metal isotopes for the study of tissues in the field of nuclear medicine is currently being developed. Metal isotopes are accumulated non-specifically in the body. Therefore, it is necessary for diagnosis and therapy to use suitable ligands, which form a thermodynamically stable and kinetically inert complex with the given metal ion, which can be attached to a suitable targeting group. Isotopes of gallium and copper are suitable for imaging od therapy. The cavity of the 1,4,7-triazacyclononane is suitable for the complexation of gallium, copper and some other metals with a small radius. However, the macrocycle itself does not form thermodynamically stable complexes, so the nitrogen atoms must be substituted by proper pendant arms, such as carboxylates. In recent years organic residues of phosphoric acids are also used. This work deals with substances that are derivatives of 1,4,7-triazacyclononane and contain phosphorus arms, which were studied in recent years. Keywords complexes, ligands, dissociation constants, stability constants
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Potential contrast agents for MRI based on manganese(II) complexes
Drahoš, Bohuslav ; Lukeš, Ivan (advisor) ; Geraldes, Carlos F. G. C. (referee) ; Toth, Imre (referee)
The thesis is focused on the synthesis and characterization of novel Mn2+ complexes as alternative to Gd3+ chelates which are wide-spread contrast agents in Magnetic Resonance Imaging (MRI). In the perspective to find suitable chelators of Mn2+ , three groups of pentadentate ligands with different size of macrocylic cavity, different donor atoms and number of pendant arms containing various functional groups have been investigated. Coordination numbers of 6 or 7 were found in the crystal structure of the Mn2+ complexes enabling binding of one or two water molecules in the first coordination sphere. The direct water coordination causes a decrease in the complex stability and thus, the thermodynamic stability of investigated chelates is lower than that of polyaminocarboxylate complexes and their dissociation is very fast in comparison to [Mn(nota)] and [Mn(dota)]2- . The studied Mn2+ complexes do not undergo oxidation in air except for complexes with 12-membered ligands which are oxidized to Mn3+ species. The proton relaxivities of the bishydrated complexes are two times higher than those for monohydrated complexes and are comparable to those of commercial contrast agents based on Gd3+ complexes. Variable-temperature 17 O NMR data revealed that the water exchange varies from slow to intermediate or...
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