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Synthesis and aplication of Dewar benzenes
Janková, Štěpánka ; Kotora, Martin (advisor) ; Roithová, Jana (referee) ; Svoboda, Jiří (referee)
Dewar benzenes are valence isomers of benzenes, which can be prepared by their thermic or photochemical rearrangement.1,2,3 They posses interesting physical and chemical properties due to the presence of the strained bicyclic framework. I studied synthesis of para-substituted phenyl Dewar benzenes and consequently kinetics of their thermal rearrangement for new information about mechanism of this unclear reaction. I also showed synthesis of new substituted aromatic and polyaromatic compounds, in which the key intermediates were Dewar benzenes (Scheme 1). Their chemical and physical properties are also going to be discussed. Scheme 1 R R R Cl3Al R + Ar COOMe RR R R COOMe Ar DMSO Me Me Me Me C6H4-X COOMe Fe n CO2MeMe Me Me Me Me Me Me R R R R S Me MeO2C EtO2C R R R R 1. van Tamelen, E. E.;Pappas, S. P. J. Am. Chem. Soc. 1962, 84, 3789. 2. Koster, J. B.; Timmermans, G. J.; van Bekkum, H. Synthesis, 1971, 139. 3. Schäfer, W.; Hellmann, H. Angew. Chem. Int. Ed. 1967, 6, 518.
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Chiral recognition by mass spectrometry
Kosíková, Lenka ; Roithová, Jana (advisor) ; Bednář, Petr (referee)
Title: Chiral recognition by mass spectrometry Author: Bc. Lenka Kosíková Department: Department of Organic Chemistry Supervisor: doc. Mgr. Jana Roithová, Ph.D. This work is focused on the use of mass spectrometry as the analytical method for chiral recognition in the gas phase. We have examined formation of complexes (S and R) isomers [dimethyl-2,2'-dihydroxy-1,1'binaphthalene-3,3'-dicarboxylate] with sodium. Chiral effect for the fomation of sodium dimers is 1,34±0,06 and that for formation of trimers 2,38±0,22 in favor of the formation of homochiral complexes. Part of the work is devoted to the preparation of isotopically labeled ester [(R)-(−)- di(D3-methyl)-2,2'-dihydroxy-1,1'binaphthalene-3,3'-dicarboxylate]. Mixing of equimolar amounts of D3-(R) and unlabeled (S) isomers leads to the artificial racemate, while we can still distinguish the enantiomers using mass spectrometry. Another part represents the study of the complex formation between (S and R) isomers of [dimethyl-2,2'-dihydroxy-1,1'binaphthalene-3,3'-dicarboxylate] with the metal complex [(S,S)-1,5-diaza-cis-decalin]Cu(OH)I depending on the molar ratios in the solution. I have showed that the molar concetration of the catalyst in the solution plays an important role in the complex formation and that the ESI source spectra of...
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Complexes of zinc salts and flavonoids
Křížová, Tereza ; Roithová, Jana (advisor) ; Volný, Michael (referee)
Modern mass spectrometry (MS) is very well suited for analysis of flavonoids and their complexes. Progress during the last two decades has made MS the most sensitive method for molecular analysis of flavonoids. MS has a potential to provide information on the exact molecular mass, as well as on the structure. Flavonoids are acting as chelating agents on various metal ions. The goal of this study was to discover, which types of ions are formed in solutions of zinc salts and flavonoids by using mass spectrometry attached with electrospray ionization. First, we have studies substructures of flavonoid - resorcin, pyrokatechin a pyron - in order to find out, how individual parts of flavonoid interact with zinc ions.
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The growth of larger hydrocarbons in the ionosphere of Titan: C9Hx 2+ + CD4
Vachelová, Jana ; Roithová, Jana (advisor) ; Žabka, Ján (referee)
Title: The growth of larger hydrocarbons in the ionosphere of Titan: C9Hx 2+ + CD4 Author: Jana Vachelová Department: Department of Organic Chemistry Supervizor: Mgr. Jana Roithová, Ph.D. Abstract Dications and multiply charged ions are studied mainly in terms of physical and chemical processes, especially in environments with extremely low temperatures and pressure. Under these conditions the production of higher hydrocarbons is not explained. The aim of this bachelor thesis was a comparison of reactivities of dications derived from three aromatic isomers (indene, methylphenylacetylene and phenylpropadiene) and determination of the dependence of the reactivities on the reaction conditions. The main experimental method was mass spectrometry. It was found that the reactivities of dications generated from indene, methylphenylacetylene and phenylpropadiene are different and depend on the reaction conditions. Key words: dications, electron ionization, mass spectrometry, isomers
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Molecular recognition in the gas phase: Chiral recognition
Vinklová, Nicole ; Roithová, Jana (advisor) ; Bednář, Petr (referee)
This thesis deals with molecular recognition of chiral compounds in the gas phase. Tandem mass spectrometry was used as a detection method in this case. Compounds, which have been studied, were MacMillan organocatalysts and proline with different chirality. Three experiments were carried out. Determination of activation energy for fragmentation of proline complexes with amines, where we have studied complexes with 2-aminobutane and 2-aminohexane of different chirality. Fragmentation studies of diastereoisomeric complexes of Cu2+ and three chiral ligands were carried out at two different collision energies. There the largest chiral effect was observed. The last topic was a measurement of the rate constants. It was aimed at dissociation and exchange reactions of complexes. Keywords: mass spectrometry, kinetic method, chiral compounds, chiral recognition, proline, organocatalysis
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Study of C-C coupling of dienes catalyzed by ruthenium(II) complexes
Hanikýřová, Eva ; Roithová, Jana (advisor) ; Jaklová Dytrtová, Jana (referee)
Title: Study of C-C coupling of dienes catalyzed by ruthenium (II) complexes. Author: Bc. Eva Hanikýřová Department: Department of Organic Chemistry Supervisor: Mgr. Jana Roithová, Ph.D. Abstract Transition metal catalyzed cycloadditions have contributed extensively to organic synthesis. The use of ruthenium complexes in those reactions gain importance due to their demonstrated ability in the catalytic carbon-carbon bond formations via ruthenacycle intermediates. In our studies, we have concentrated on the interaction between ruthenium (II) and alkenes using mass spectrometry with electrospray ionization. This technique allows to investigate ruthenium complexes in the ionized states, and allows to investigate these structures by using MS/MS analyse. Our experimental research was complemented by quantum chemical calculations using Density functional theory. The research leads to a more detailed understanding to Ruthenium complexes with unsaturated hydrocarbons reaction mechanism. Key words Gas-phase chemistry, Reaction mechanisms, Electrospray Ionization, Catalyst, [CpRu(CH3CN)3]PF6, Mass Spectrometry
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Complexes of iron(II) salts and flavonoids
Schröpferová, Tereza ; Volný, Michael (referee) ; Roithová, Jana (advisor)
This work is devoted to a study of the interaction between iron(II) ions and flavonoids (epicatechin, catechin, quercetin) by means of mass spectrometry and electrospray ionization. First, a measurement with model molecules (pyrocatechol, resorcinol, 3-hydroxy-2-methyl-4- pyrone) has been performed in order to find how iron(II) intereacts with the OH groups on the hydrocarbon rings. It has been found that Fe2+ coordinates to epicatechin and probably also catechin (the measurement with catechin was unsuccesfull because of contamination by sodium) between the OH groups at the ring B and the fragmentation of the complex can proceed via a retro-Diels-Alder's reaction and thus lead to cleavage of the pyrone ring. Quercetin has at the pyrone ring the keto function next to the OH group, therefore the iron ion binds to these functions rather than to the OH groups at the ring B. Accordingly, the retro- Diels-Alder's reaction is not possible and the complex loses only small molecules of water and carbon oxide from the side rings as it was found for the complexes of model molecules.
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Properties of bipyridine N,N'-dioxides in the gas phase
Ducháčková, Lucie ; Kotora, Martin (referee) ; Roithová, Jana (advisor)
Lucie Ducháčková Bipyridine N,N'-dioxides are organocatalysts, which are used as a chiral Lewis bases in enantioselective catalysis. The aim of this diploma thesis was systematic investigation of the proton affinities of bipyridine N,N'-dioxide derivatives. Further, the complexation properties and chiral recognition in the gas phase of bipyridine N,N'-dioxide derivatives were examined. Mass spectrometry complemented with infrared multiphoton dissociation spectroscopy and quantum-chemistry calculations using the density functional theory (DFT) were used as the main experimental methods. Bipyridine N,N'-dioxides are a new class of oxygen superbases with proton affinities larger than 1030 kJ/mol. Complexation properties and reactivities of their metal complexes are comparable to 2,2'-bipyridine.
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