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Chemical and Physical Properties of Single Molecules and Their Assemblies Adsorbed on Solid Surfaces
Houska, Václav ; Starý, Ivo (advisor) ; Mazal, Ctibor (referee) ; Církva, Vladimír (referee)
Interaction of organic molecules with solid surfaces represents a key area of physical-chemistry research. From heterogenous catalysis to OLED displays, in numerous such systems molecules interact on interfaces, and understanding their behavior is crucial for the correct operation of such applications. In this work, I focused on the study of large π-conjugated macrocycles based on dibenzo[5]helicenes with emphasis on their behavior on graphite surface. The chemical synthesis of the investigated macrocycles was initially impeded by a number of obstacles, particularly by their extremely low solubility. In this work, an efficient solubilization strategy based on the modification of the macrocycles with trityl groups was discovered, which effectively diminishes the intense intermolecular π-π interactions. This opened a path towards a subsequent study of the compound's properties. The attention was focused mainly on a trimer, which was successfully fully characterized, enabling further experiments. Since only a few tens of milligrams of the trimer was prepared, and some stereoisomers were isolated in only microscopic amounts, it was important to develop a suitable experimental methodology. These methods were successfully employed in the measurement of the isomerization kinetics, which allowed us to map...
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Synthesis of helical aromatics for applications in enantioselective catalysis and nanoscience
Klívar, Jiří ; Stará, Irena (advisor) ; Hrdina, Radim (referee) ; Církva, Vladimír (referee)
The aim of this work was to explore the scope and limitations of [2+2+2] co- cyclotrimerization of cyanodiynes in the preparation of conformationally stable and optionally optically pure azahelicenes, helically chiral bipyridines and helicenes laterally extended by a pyridine unit. As a key reaction for the construction of a helical skeleton, crucial [2+2+2] (co-)cyclotrimerization mediated by various transition metal complexes was chosen for the preparation of racemic azahelicenes. Oligoynes as key intermediates were prepared by a sequence of Sonogashira and Suzuki-Miyaura coupling. For optically pure azahelicenes and bispyridohelicenes, a sequence of Sonogashira and Suzuki-Miyaura coupling and Mitsunobu reaction was used. Importantly, the Mitsunobu reaction was used for its extraordinary ability to transfer chirality from the starting chiral alcohol to the early helicene precursor without configurational scrambling. It is worth noting that optical purity of the key oligoynes have crucial role in the chirality transfer to final azahelicenes or bispyridohelicenes. An in situ generated Ni(0) catalyst was used for bispyridohelicenes with a connection in the 2,2'-position, which enabled both [2+2+2] cyclotrimerization and Ullmann-type coupling. The conformationally stable racemic aza[6]- and...
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Azidoperfluoroalkanes: Synthesis and Application
Blastik, Zsófia Eszter ; Beier, Petr (advisor) ; Církva, Vladimír (referee) ; Kvíčala, Jaroslav (referee)
The incorporation of the trifluoromethyl and perfluoroalkyl motifs into organic compounds has been a hot topic in synthetic organofluorine chemistry. There is a plethora of methods for the introduction of the CF3 moiety at carbon, oxygen and sulfur centers. In sharp contrast, methods for synthesizing N-trifluoromethyl and N-perfluoroalkyl compounds are very limited and new approaches are highly sought-after. The scarcity of these compounds prompted us to develop reagents capable of transferring the perfluoroalkyl unit to nitrogen atom. To fulfil this purpose, we have regarded azidoperfluoroalkanes as ideal reagents, therefore, this thesis is concerned with the synthesis and applications of these azides. The first part describes the preparation of azidoperfluoroalkanes. Upon activation by cesium fluoride, TMSCF3 transfers the trifluoromethyl group to an electrophilic azide to produce the desired azidotrifluoromethane. Longer carbon chain azidoperfluoroalkanes were prepared in a similar way, starting from the corresponding organosilane. A different synthetic strategy was applied for the preparation of azidopentafluoroethane where the perfluoroalkyl anion was generated from pentafluoroethane with n BuLi, followed by the addition of tosyl azide. The isolation of these fluorinated azides was...
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Complexation Properties of Aza[n]phenacene Ligands.
Váňa, Lubomír ; Žádný, Jaroslav ; Storch, Jan ; Církva, Vladimír
This work is aimed at the synthesis of new aza[n]phenacenes 2 (n = 4 or 5, Ar = phenyl or 2-pyridyl), where [njphenacenes 1 with ö-lactam ring are used as starting material. The resulting compounds are subsequenttly investigated in terms of their complexation properties with transition metals (Cu, Ni, Co, Pt, Ir) due to their potential application as photoluminescent complexes.
Fulltext: content.csg -  DOC
Plný tet: 00206B6C274C191114122808 - DOC
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Synthesis and Functionalization of Phenacenes Containing δ-Lactam Ring.
Váňa, Lubomír ; Církva, Vladimír ; Pfleger, Jiří ; Storch, Jan
This work is aimed at the development of a new efficient methodology towards the synthesis of various aza[5]phenacenes containing δ-lactam ring in their structure. Possibilities of their functionalization or derivatization are also discussed, along with complexation properties of suitable aza-derivatives as ligands in transition-metal complexes. The resulting compounds are investigated in terms of their material properties, especially for the formation of thin film structures capable of an efficient semi-conductivity or their potential application as photoluminescent complexes in OLEDs.
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Photochemical Synthesis of Aza-aromatic Compounds.
Kos, Martin ; Žádný, Jaroslav ; Storch, Jan ; Sýkora, Jan ; Církva, Vladimír
Herein we report synthesis of series of novel both aza- and diaza-helicenes, and phenacenes, which were prepared mainly by photocyclization of corresponding imine precursors. Reaction conditions of photocyclization (i.e. solvent, photocatalyst, type of irradiation, use of water scavenger) were optimized and enhanced. Usage of TEMPO as oxidizing agent leads to improvement of yields up to 72 %. Prepared 2-pyridyl substituted azaphenacenes will be utilized for preparation of potential semiconductive layers in cooperation with IMC of the CAS.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22017111612580 - PDF
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