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Catalytic synthesis of polyanilines
Bláha, Michal ; Vohlídal, Jiří (advisor) ; Omastová, Mária (referee) ; Trchová, Miroslava (referee)
This Ph.D. thesis is dealing with catalytic polymerization of aniline (ANI) and partially also of substituted anilines with FeCl3/H2O2 catalyst system, in which according to obtained results both active species, Fe3+ and HO , participate in the overall polymerization mechanism, creating a synergic system. The Fe3+ /H2O2 catalyst system, also called Fenton's system can considerably lower contamination of forming neat polyanilines (PANIs) by side-products characteristic of stoichiometric polymerization. However, catalytically prepared PANIs exhibit reduced conductivity related most probably to side reactions involving radicals generated as integral components of the FeCl3/H2O2 system. Catalytic polymerization of ANI with FeCl3/H2O2 system was found to be the reaction of approx. 2nd order with respect to ANI and gives PANIs of a good quality only when [H2O2] in the reaction mixture was kept low, i.e., at under- stoichiometric ratios [H2O2]/[ANI]. At over-stoichiometric ratio [H2O2]/[ANI], PANIs of lowered conductivity, worse spectroscopic characteristics and increased size of PANI nanostructures were obtained; nevertheless, these PANIs were not over-oxidized to pernigraniline state. The reaction-time profiles of the open-circuit potential of reaction mixtures exhibited an inflection related to the...
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Preparation of cyclic derivatives of amino acids using a combination of organocatalysis and metal catalysis
Měrka, Pavel ; Veselý, Jan (advisor) ; Rýček, Lukáš (referee)
This diploma thesis is focused on the combination of enantioselective organocatalysis and transition metal catalysis. In the experimental part of the work, the optimization of reaction conditions with respect to the reaction yields, enantioselectivity and diastereoselectivity was solved. The applicability of the reaction was verified on various substrates. The second part of the work is focused on the study of the mechanism of the reaction using the methods of quantum chemistry. The kinetics of the reaction were monitored by NMR spectroscopy and the mechanism of the reaction was investigated by quantum chemistry methods. Keywords: aminocatalysis, palladium, synergistic catalysis, reaction mechanism, DFT
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Theoretical studies of catalysts for Suzuki-Miyaura reaction
Měrka, Pavel ; Uhlík, Filip (advisor) ; Srnec, Martin (referee)
This thesis is focused on theoretical study of Suzuki-Miyaura cross- coupling reaction catalyzed by palladium complex with phosphinopherrocene li- gand. The aim of this work is to provide basic image of the catalytic cycle with newly prepared coordination compounds of palladium. Bromobenzene and phe- nyltriolborate were chosen as the model reagent. DFT method M06-2X was used for characterization of molecular goemetries of intermediates and most important transition states for all parts of catalytic cycle.
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Research of gold catalyzed reactions
Jašíková, Lucie ; Roithová, Jana (advisor) ; Polášek, Miroslav (referee) ; Starý, Ivo (referee)
The main focus of the current dissertation thesis is research of gold catalyzed reactions. I was using mass spectrometry as the primary research technique. I complemented the results with infrared multiphoton dissociation spectroscopy, nuclear magnetic resonance spectroscopy and quantum chemical calculations. I have investigated the interaction of the gold(I) cation with unsaturated hydrocarbons in the first part of my thesis. Secondly, I have studied gold(I) or silver(I) affinity to gold acetylides. In the last part, I have investigated the reaction mechanism of a gold mediated addition of methanol to alkynes. I found out that the gold(I) cation interacts stronger with gold acetylides than with nonactivated triple CC bonds. I showed that the complexes containing two gold atoms represent the key intermediates in the mechanism of addition of methanol to alkynes and that the ligand on the gold catalyst plays a fundamental role in the determination of the mechanism. Powered by TCPDF (www.tcpdf.org)
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Mechanism of copper mediated oxidative coupling of naphthols
Schröpferová, Tereza ; Roithová, Jana (advisor) ; Polášek, Miroslav (referee)
The 2,2'-disubstituated 1,1'-binaphthyls (BINOLs) are important ligands in enantioselective synthesis . The major approach for their preparation is based on transition-metal-mediated oxidative C-C coupling of 2-substituted naphtalenes. This diploma thesis examined the mechanism of the coupling reaction in the gas phase using mass spectrometry with electrospray ionization. The aim of this thesis was to compare the selectivity of the copper(II)- catalyzed coupling reaction of 2-naphthol and its derivative with an electron-withdrawing group, to detect possible reaction intermediates, and to determine the origin of the preference of the cross-coupling. The electron-withdrawing group of naphthol slows down the coupling reaction which enabled us to detect the reaction intermediates. The intermediates in the reaction of 2-naphthol were not observed, because the coupling reaction proceeds too quickly. Hence, we have observed only complexes of the coupling products. The preferential cross coupling was explaned on the basis of an interplay between the probability of the formation of binuclear copper complexes and the reactivity of such complexes.
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Catalytic synthesis of polyanilines
Bláha, Michal ; Vohlídal, Jiří (advisor) ; Omastová, Mária (referee) ; Trchová, Miroslava (referee)
This Ph.D. thesis is dealing with catalytic polymerization of aniline (ANI) and partially also of substituted anilines with FeCl3/H2O2 catalyst system, in which according to obtained results both active species, Fe3+ and HO , participate in the overall polymerization mechanism, creating a synergic system. The Fe3+ /H2O2 catalyst system, also called Fenton's system can considerably lower contamination of forming neat polyanilines (PANIs) by side-products characteristic of stoichiometric polymerization. However, catalytically prepared PANIs exhibit reduced conductivity related most probably to side reactions involving radicals generated as integral components of the FeCl3/H2O2 system. Catalytic polymerization of ANI with FeCl3/H2O2 system was found to be the reaction of approx. 2nd order with respect to ANI and gives PANIs of a good quality only when [H2O2] in the reaction mixture was kept low, i.e., at under- stoichiometric ratios [H2O2]/[ANI]. At over-stoichiometric ratio [H2O2]/[ANI], PANIs of lowered conductivity, worse spectroscopic characteristics and increased size of PANI nanostructures were obtained; nevertheless, these PANIs were not over-oxidized to pernigraniline state. The reaction-time profiles of the open-circuit potential of reaction mixtures exhibited an inflection related to the...
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Structure Analysis of Plant Bifunctional Nuclease TBN1
Kovaľ, Tomáš ; Dohnálek, Jan (advisor) ; Brynda, Jiří (referee) ; Schneider, Bohdan (referee)
This work is dedicated to thorough structural analysis of plant bifunctional nuclease TBN1, the representative of plant nuclease I group. TBN1 along with homologous nucleases from this family plays an important role in plant cell life cycle and also shows considerable anticancerogenic effects. Two variants of TBN1 (wild type and N211D mutant) were studied. Properties of both variants in different solutions were analyzed. Both were successfully crystallized. Structures of both types of TBN1 were solved using X-ray diffraction. The phase problem was solved by Multi-wavelength anomalous dispersion using Zn2+ ions natively present in TBN1. Structural properties of TBN1 such as fold, active site composition, effect of glycosylation and surface electrostatic potential distribution were analyzed. Reaction mechanism of TBN1 was proposed on the basis of structural properties and comparisons with similar structures.
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