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Study of derivatization reactions for ESI-MS analysis of hardly ionizable rhenium aryl chlorocomplexes
Vlk, Mikuláš ; Štícha, Martin (advisor) ; Kozlík, Petr (referee)
Mass spectrometry with electrospray ionization is an excellent method for structural analysis of coordination compounds with outstanding sensitivity and selectivity. However, it fails to detect some low-polar rhenium complexes. This master thesis describes derivatization method of non-ionizable rhenium complexes with 1,2-dihydroxybenzene and 2,3- dihydroxytoluenene. Fragmentation mechanisms and structure of prepared complexes was studied using high resolution mass spectrometry and collision-induced dissociation (CID). Furthermore, density functional theory (DFT) computational method was used for prediction of bond cleavage based on bond lengthening.
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Chemical treatment of weakly ionizable uncharged complexes of rhenium for the possible identification by ESI-HRMS
Málková, Nikola ; Štícha, Martin (advisor) ; Kozlík, Petr (referee)
Detailed characterization of rhenium complexes is necessary for the potential use in clinical practice and nuclear medicine. For structure characterization and quantification of coordination compounds, mass spectrometry exceeds other analytical methods in sensitivity and selectivity. The advantage of this method for coordination chemistry is the possibility of determination of the analyte directly in the reaction mixture. The compounds need to be ionized to get relevant mass spectra. The ionization of these compounds is often very difficult and it is necessary to develop a special derivatization procedures. Complexes of rhenium with 1,2-dihydroxybenzene and 4-methyl-1,2-dihydroxybenzene and it's derivatives with p- chloroaniline and p- bromoaniline have been prepared and characterized by ESI-HRMS. The fragmentation mechanisms of these complexes have been studied using a mass spectrometry technique collision-induced dissociation (CID). Keywords Rhenium complexes, rhenium, 1,2-dihydroxybenzen, 4-methyl-1,2-dihydroxybenzen, mass spektrometry, derivatization, ESI-MS, CID
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Analytical study of reduction of ammonium perrhenate using selected reduction agents
Lišková, Jana ; Jelínek, Ivan (advisor) ; Dian, Juraj (referee)
This thesis is focused on analysis of reduction of ammonium perrhenate using less frequent reducing agents. Ascorbic acid and acetylhydrazine were chosen as less common reducing agents. Reductions were observed leveraging capillary zone electrophoresis and UV/Vis spectroscopy. Measurements were carried out both in acidic and in basic environments. Reduction of peak area of ammonium perrhenate was observed using capillary zone electrophoresis after addition of reducing agent. Rate of absorption of ammonium perrhenate was monitored with UV/Vis spectroscopy. Furthermore, the possibility of shifting the equilibrium of the reaction to the benefit of the reduction products was monitored by the addition of the complexing agent. Py- rogallol (benzene-1,2,3-triol) was used as the ligand and acetylhydrazine was selected as the reducing agent. The reduction was monitored by capillary zone electrophoresis. The identity of the resulting complex was confirmed with ESI/MS. Keywords rhenium, rhenium complexes, ascorbic acid, acetylhydrazine, capillary zone electrophore- sis, UV/Vis spectroscopy, mass spectrometry
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Utilization of mass spectrometry and other analytical techniques for analysis of rhenium complexes
Vaňátková, Petra ; Jelínek, Ivan (advisor) ; Smrček, Stanislav (referee)
Rhenium complexes coordinated with suitable organic ligand gain increased interest in radiopharmaceutical medicine. Besides suitable radiological properties given by a metal ion itself, detailed knowledge of overall chemical properties of formed complexes, namely their exact structures, chemical stabilities and possible degradation pathways are essential pre-requisites for their clinical application. Selected rhenium complexes with pyrogallol 2,3-dihydroxynaphthalene and catechol as strongly bound ligands were prepared by a reaction of tetrabutylammonium tetrachlorooxorhenate with twofold molar excess of ligand in presence of various amount of triethylamine. The structures of formed complexes and their consequent reaction products were estimated by means of mass spectrometry with electrospray ionization. The kinetics of reactions in course of complex formation and consequent decomposition were primarily followed by UV- Vis absorption spectra measurement, complemented by single or continuous electrospray mass spectrometry analyses. Optimized HPLC and CZE procedures were utilized for monitoring of the composition of reaction mixtures in course of Re complex formation and for purity check of prepared complexes. Semi-preparative HPLC mode was succesfully utilized for isolation and final purification of...
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