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Immobilised palladium catalysts
Demel, Jan ; Štěpnička, Petr (advisor) ; Vohlídal, Jiří (referee) ; Jirátová, Květa (referee)
Shrnutí V rámci této diplomové práce byl připraven nový komplex [RuCl2(46-1-iso- propvl-4-nrethvlbenzen) { 1'- (dífenvlfosfi no) ferrocenkarboxvlová kvselina-rc P}] a byla stanovena jcho struktura rcntgcnovou difrakcí na monokrystalu. Na tttesoporézltírnolekulové Síto MCM-41 byl zakotvelr kornplex rutltelria dvěuta způsoby.V prvním případě, kdy byla na MCM-41 nejprve zakotvena Hdpf a poté ruthenatý komplex' došlo pravděpodobně k nezávislému zakotvení obou látek. V druhém případě byl ruthenatý konrplex zakotven přímo bez fosfinového linkeru. Tyto molekulový i oba lreterogenni katalyzátory byly použity ke stu- dirt reakce propargylalkoholu s kyselinou benzoovou , za vznikt 2_oxopropvl_ bcnzoátu. oba hctcrogcnní katalyzátory mčlypodobnou aktivitu, cožuka- zuje,že v tottrto případě nezáleželo Ita přítolttttosti fosfinovélro ligandu. Velrrri nízká aktivita heterogenních katalyzátorů v porovnání s homogenním byla způsobena paralelní reakcí propargylalkoholu s křemičitanovým molekulo- vým sítem MCM-41 na neidentifikovaný, pravděpodobně polymerní produkt. Bylo zjištěno, žekatalytická centra se z heterogenních kata|yzátorů vymý- vají, ale v tak malém množství,žerrmožtiu.jíminimálně ještě jedno porržití kataIyzátoru bez výrazné ztráty aktivity'
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Orgonophosphorus analogues of triphosphate
Šrein, Jakub ; Kubíček, Vojtěch (advisor) ; Štěpnička, Petr (referee)
Two substances were prepared in this work, both with PCPCP structure motif. The motif is similar to ATP molecule, although the oxygen bridges are replaced with methylene groups. Both compounds were characterized by mass spectrometry and NMR spectroscopy. Since bis(methylenephosphonato)phosphinate is soluble in water, four pKa values were determined. Both prepared compounds have potential to serve as chelating ligands. Powered by TCPDF (www.tcpdf.org)
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Salts of 2-aminoethanol and ferrocene-based acids
Zábranský, Martin ; Štěpnička, Petr (advisor) ; Němec, Ivan (referee)
Combination of the compact but sterically flexible ferrocene scaffold with intermolecular binding potential and conformational variability of (2-hydroxyethyl)ammonium structural motif was utilised in the construction of solid crystalline materials. Crystallisation in systems containing ferrocenecarboxylic, 2-ferrocenylacetic, 3-ferrocenylpropionic, 3-ferrocenyl- acrylic, 3-ferrocenylacrylic, 3-ferrocenylpropiolic, ferrocene-1,1'-dicarboxylic or ferrocene- sulfonic acid with 2-aminoethanol afforded crystals of the corresponding salts. The resulting crystalline products were characterised with the usual methods (proton nuclear magnetic resonance, infrared spectroscopy, elemental analysis) and their crystal structures were determined by means of single-crystal X-ray diffraction analysis. The crystal structures of the salts mentioned above usually contain rather complicated two dimensional networks of charge-assisted hydrogen bonds. With the aim of studying potentially more simple hydrogen-bonded structures, additional crystallisation experiments were conducted in systems of ferrocenecarboxylic acid and 2-(methylamino)ethanol or 2-(dimethylamino)ethanol. These experiments yielded simple salt of the former amine and adducts of salts of both bases with ferrocenecarboxylic acid in the ratio of 1:1. The...
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MRI contrast agents based on saturation transfer
Krchová, Tereza ; Kotek, Jan (advisor) ; Štěpnička, Petr (referee)
Title: MRI Contrast Agents Based on Saturation Transfer Author: Bc. Tereza Krchová Department: Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague Supervisor: doc. RNDr. Jan Kotek, Ph.D. Supervisor's email: modrej@natur.cuni.cz Abstract: The aim of this thesis was to synthesize macrocyclic ligands (based on the DO3A and DO2A framework) with exchangeable protons on the aminic coordinating groups that could be (after the complexation with suitable paramagnetic metal ions) potential contrast agents based on saturation transfer, so called CEST contrast agents (Chemical Exchange Saturation Transfer). Two ligands H3L1 and H2L2 with one and two aminoethyl groups have been synthesized. The structurally similar ligands H3L1 Me and H3L1 2Me with one exchangeable proton and without it have been also prepared. The protonation constants of the ligands H3L1 and H2L2 have been determined by pH 1 H NMR and potentiometric titrations. The stability constants of metal ion complexes with H3L1 and H2L2 have been also determined by potentiometry. The CEST effect of Eu3+ and Yb3+ complexes with H3L1 , H3L1 Me and H3L1 2Me in solution have been studied. The residence lifetime of the inner-sphere water molecule has been determined for Gd-L1 complex. Keywords: CEST, MRI, aminoethyl, DO3A, DO2A, 17 O...
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Palladium catalysts deposited over novel siliceous supports
Křečková, Pavlína ; Štěpnička, Petr (advisor) ; Sedláček, Jan (referee)
Title: Palladium catalysts deposited over novel siliceous supports Author: Pavlína Křečková Department: Department of Inorganic Chemistry, Faculty of Science, Charles University in Prague Supervisor: prof. RNDr. Petr Štěpnička, Ph.D. Supervisor's e-mail address: stepnic@natur.cuni.cz Advisor: prof. Ing. Jiří Čejka, DrSc. Advisor's e-mail address: jiri.cejka@jh-inst.cas.cz Abstract Keywords: palladium; deposited catalysts; siliceous supports; C-C coupling reaction. The aim of this work was to prepare a deposited palladium catalyst from Pd2+ and twodimensional zeolite ITQ-2 bearing ≡SiCH2CH2CH2NHCH2CH2NEt2 groups at the surface. This catalys has been evaluated in the Heck reaction between n-butyl-acrylate and brombenzene to give n-butyl-cinnamate. Influence of the reaction temperature, the solvent, base and hydrate water on the progress of the Heck reaction was investigated. This work also deals with the possibility of recycling the catalyst and, due to its nature, with the quantity of leached palladium into the reaction mixture. Furthermore, the work describes differences in morphology between the fresh and a recycled catalyst.
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