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Acidobasic behavior of carboxymethylcellulose solutions
Teslíková, Ivana ; Kislinger, Jiří (referee) ; Janeček, Jiří (advisor)
This work concerns with the study of acidobasic behavior of solutions of sodium salts of carboxymethylcellulose (CMC-Na). This behavior was investigated using acidimetric titrations of the salt solutions with potentiometric and conductometric indications. In order to determine the content of carboxylic groups in two different samples of CMC-Na (M1=90 kDa, DS1=0.7; M2=700 kDa, DS2=0.9), we employed the method of Ray von Wandruzska, originally proposed for the determination of the acidity of humic substances. The values of the degree of substitution (DS) obtained using this method correspond to the values declared by the producer. The small differences (of the order few percentage points) can be attributed to the humidity of the samples. The acidimetric titrations were performed also for solutions with different ionic strengths. There is an apparent effect of the ionic strength on the shape of titration curves; nevertheless these data were not used for any theoretical interpretation.
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Device for measurement of electrochemical cells characteristics by the cyclic voltammetry
Kučera, Vojtěch ; Bilko, Radek (referee) ; Lábus, Radek (advisor)
The thesis deals with observation of cells parameters. One of the potential solutions for observing the characteristics of cells are utilization the electrochemical analyse called voltametry. Its fundamental consists of loading variable voltage in between two electrodes dipped in electrolytic solution and monitoring flowing current. The point of the thesis is to build up the measuring workplace, which can provide this measurement. We suggest utilization of modern laboratory technique and connection the measuring instruments with PC. The first part of the thesis deals with theoretical knowledge of used functions and describes theirs mathematics definitions. The second part deals with proceeding of workplace realization, instrument connection with PC and development application in computer’s language. Result is measuring workplace, which can provide observing cells according to entered parameters.
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Ditopic ligand based on 1,4,7-triazacyclononane
Kačmarčík, Jaroslav ; Kubíček, Vojtěch (advisor) ; Kotek, Jan (referee)
The radioisotopes 64 Cu and 68 Ga are used in radiomedicine and imaging (PET) due to their properties. The metal ion must be complexed with a suitable ligand forming a stable and kinetically inert complex. The aim of this bachelor thesis was to synthesize polydentate ligand based on the TACN macrocycle, followed by the preparation of its gallium (III) and copper (II) complexes. Based on the dependence of absorbance A on the wavelength λ, d-d transitions in the VIS (λ = 440 - 800 nm) region and CT transitions with transitions on the aromatic cycle in the UV region (λ = 220 - 380 nm) for the [Cu(L)] were also observed. The [Cu(L)] complex was studied by UV-VIS titration. The complex [Ga(L)] was also synthesized, but its further characterization and study of coordination properties were not carried out. Key words: macrocyclic ligands, complexes, stability, radiomedicine, PET
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Sensory analysis as a means to increased transparency of analytical methods used in practical chemistry education
Kocichová, Kristýna ; Rusek, Martin (advisor) ; Kolář, Karel (referee)
The theoretical part of the thesis is focused on the description of sensory analysis, its history, basic methods, principles, and procedures in the analysis of solutions. It specializes in three basic tastes: salty, sour and bitter. It then focuses on explaining the basic analytical methods whose applications can be found in practical chemistry teaching, in particular an introduction to the principles of conductometry, spectrophotometry and potentiometry. It then addresses the issues of science teaching, language and the difficulty to learn these sciences. The aim of this bachelor thesis was an attempt to increase the transparency of analytical methods in practical chemistry teaching through sensory analysis methods. Building on previous work addressing this issue, further experimental activities were designed and piloted. These activities give the possibility to increase first of all the interest and motivation of the students in chemistry, then to lead the students to think on their own, to find new solutions, to be able to work with the instruments within the analytical methods and to verify and compare the results of the measurements. The activities have been validated on chemistry teacher education students and are included in the practical part divided into sensory and instrumental parts. The...
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Trivalent and tetravalent metal complexes for radiodiagnostics
Hacaperková, Eliška ; Kubíček, Vojtěch (advisor) ; Drahoš, Bohuslav (referee) ; Polášek, Miloslav (referee)
Fluorine-18 is the most utilized nucleus for positron emission tomography (PET). In 2009, incorporation of fluorine-18 to the coordination sphere of Al(III) was introduced as a new alternative for commonly employed compounds with F-C bond. Such a radiotracer consists of two parts: a metal complex with a fluoride and a peptide or a small/part of biomolecule. Shortly after that, first clinical studies showed a promising potential of such com- pounds for clinical use. Despite a great number of papers dealing with this issue, the research is mostly application-driven and focused on the peptide part of the molecule responsible for specific accumulation within the organism. Studies oriented on a sta- bility of metal-ligand-fluorine ternary system are rather rare and only very little is known about such a three-component system from a chemical point of view in gen- eral. However, stability of F-Al bond strongly dependents on the chemical structure of other ligands in the coordination sphere. Pendant arms of a hexadentate ligand (usually used for Al(III) complexation, e.g., H3NOTA) can compete with fluoride and cause its release which leads to unspecific radioactivity accumulation. Lower ligand denticity should increase the F-Al bond stability, but can decrease the stability of the whole complex at the...
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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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Lanthanide macrocyclic complexes with phosphonate/phosphinate pendant arms
Procházková, Soňa
Imaging methods have become an integral part of diagnostic and therapeutic procedures in current medicine. Contrast agents based on metal complexes are often used to improve the final image. Complexes contain radioisotopes in nuclear medicine and gadolinium(III) ion in MRI. These complexes have to show high kinetic and thermodynamic stability and their preparation must not be time consuming. H4DOTA and its derivatives are convenient type of ligand for the formation of stable complexes. This work has focused on phosphonate and phosphinate derivatives of the ligand H4DOTA. The studied compounds can be divided into ligands containing only methylphosphinate/phosphonate (H4DO3APH, H5DO3APOH) and ligands with a second coordination center (H6DO3APIDA, H5DO3APPIN, H4DO3APAM, H8DO3APBP a H7DOTAMBP). The work has examined the possibilities of influencing the way and rate of complexation under different conditions. In order to approach the preparation conditions of radio complexes, kinetics measurements were performed not only under the metal ions excess, but also under the ligand excess. The aim was to compare the results of both types of measurements, which often showed to be different. A mechanism for the formation of various types of intermediates formed during complexation has been proposed. The...
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Study of thermodynamic stability of complexes with polydentate ligands
Böhmová, Zuzana ; Kubíček, Vojtěch (advisor) ; Vojtíšek, Pavel (referee)
Acid-base and coordination properties of macrocyclic ligand 1-oxa-4,7- diazacyclononane-4,7-bis(methylenephosphonic acid) were investigated. Protonation constants and stability constants with Ca2+ , Mg2+ , Cu2+ , Zn2+ , Mn2+ a Ga3+ metal ions were determined by potentiometry. Keywords Potentiometry, coordination chemistry, azacycles.
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Polydentate aminodiphosphinates
Böhmová, Zuzana ; Kubíček, Vojtěch (advisor) ; Vojtíšek, Pavel (referee)
Two linear aminodiphosphinates (H3L1 , H5L2 ) and one cyclic aminodiphosphinate (H2L3 ) were prepared and studied. Newly prepared compounds were characterized by NMR, MS and EA (elemental analysis). Acid-base and coordination properties of ligands were studied. Protonation constants and stability constants of complexes with Zn2+ , Ni2+ and Cu2+ metal ions were determined by potentiometry. Keywords Ligands, dissociation constants, potentiometry, phosphinates, complexes.
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