|
| |
|
| |
|
|
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...
|
|
|
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.
|
|
| |
|
| |
|
| |
|
|
Synthesis and catalytic properties of phosphinoferrocene guanidine
Bárta, Ondřej ; Štěpnička, Petr (advisor) ; Vojtíšek, Pavel (referee)
Title: Synthesis and catalytic properties of phosphinoferrocene guanidine Author: Ondřej Bárta Institution: Faculty of Science, Charles University in Prague, Department of Inorganic Chemistry Supervisor: prof. RNDr. Petr Štěpnička, Ph.D. Polar phosphine ligands proved to be useful in homogeneous and biphasic catalysis. Most of these phosphines bears anionic functional groups. On the other hand, functionalization of phosphines by cationic substituents is still quite uncommon, although these functional groups possess properties that could improve catalytic performance of the catalyst. In this regard, nitrogenous bases are particularly attractive due to their inherent basicity and the ability to enter into hydrogen bonding interactions. This thesis describes the synthesis of a novel ferrocene-based phosphine functionalized with guanidine moiety, viz. N-[1′-(diphenylphosphino)ferrocenylmethyl]guanidine (3). This compound was obtained by direct guanylation of 1′-(diphenylphosphino)- 1-(aminomethyl)ferrocene (2) (see scheme). Compound 3 was further used to prepare palladium complexes including the unusual zwitterionic complex [PdCl3(3H)]. The molecular structures of the prepared complexes were determined by X-ray diffraction analysis. Catalytic properties of phosphine 3 and complex [PdCl3(3H)] were...
|
|
| |
|
|
Polar phosphinoferrocene ligands with hydrocarbyl bridges
Zábranský, Martin ; Štěpnička, Petr (advisor) ; Dostál, Libor (referee) ; Šebesta, Radovan (referee)
A new synthetic route towards methylene-spaced hybrid phosphinoferrocene ligands was developed, making use of a phosphinoferrocene betaine 3-(N,N,N-{[1'-(diphenylphosphino)- ferrocenyl]methyl}dimethylammonium)propane-1-sulfonate (2), that is readily accessible from 1-(diphenylphosphino)-1'-(N,N-dimethylaminomethyl)ferrocene (XIX) via treatment with 1,3-propanesultone. The betaine 2 was reacted with sodium alkylsulfinates (alkyl = methyl, phenyl, 4-tolyl) to afford the corresponding sulfones 4. The coordination chemistry of [1'-(diphenylphosphino)ferrocenyl]methyl(methyl)sulfone (4a) was investigated in its zinc(II) complexes. Surprisingly, only insoluble mixed-metal coordination polymers of the general formula [MZnX3(4a)(MeOH)]n (M/X = Na/Br, K/Br, Na/I) and six-centre complex [Li2Zn2Br6(4a)2(MeOH)4(H2O)] could be obtained. Two isomeric homologues of 1'-(diphenylphosphino)ferrocene-1-carboxylic acid (Hdpf, II), viz. 1'-(diphenylphosphino)ferrocenylacetic acid (HIIa) and 1'- [(diphenylphosphino)methyl]ferrocene-1-carboxylic acid (HIIb), were prepared and their coordination preferences were assessed in their palladium(II) complexes. The palladium(II) complexes were prepared by reacting various (acetylacetonate)palladium(II) precursors with these acids with concomitant release of acetylacetone....
|
guest ::
