National Repository of Grey Literature 7 records found  Search took 0.00 seconds. 
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...
Synthesis and properties of complex π-electron systems with helical chirality
Houska, Václav ; Stará, Irena (advisor) ; Machara, Aleš (referee)
Planar shape-persistent macrocycles have been known for a long time and are routinely synthesized today. Non-planar 3D structures, however, still remain challenging synthetic targets in many cases. The objective of this Thesis was to develop a synthetic route to shape-persistent macrocycles containing dibenzo[5]helicene or its derivatives as structural units employing alkene and alkyne metathesis. The Introduction focuses on various methods of the macrocycle synthesis, on alkyne metathesis, and synthesis of helicenes is shortly reviewed as well. Then, the first part of Results and discussion describes the synthesis of 3,16-dichlorodibenzo[5]helicene and its derivatives. In the second part, the macrocycle synthesis from these dibenzohelicenes is discussed. The Experimental part provides a detailed description of performed experiments along with characterization of all new compounds prepared.
Mathematical method for submolecular resolution of helicene-based macrocycles by atomic force microscopy in air
Ukraintsev, Egor ; Houska, Václav ; Vacek, Jaroslav ; Starý, Ivo ; Stará, Irena G. ; Rezek, B.
We introduce a straightforward mathematical method for improving the AFM image resolution, applied to image analysis of helicene-based macrocycles adsorbed on HOPG. The method reveals structural details from insufficiently resolved AFM images and attributes them to internal structure and ordering of the macrocycles. Our findings are also corroborated by molecular mechanics simulations, validating that the structure provided by the method has lower potential energy compared to other tested macrocycle arrangements.
pi-Conjugated oligomers comprising helically chiral units
Houska, Václav ; Starý, Ivo (advisor) ; Machara, Aleš (referee)
The synthesis of large, shape-persistent, trimeric macrocycles comprising helical units was investigated. Since the previous synthetic approaches studied in our group failed (mainly alkene and alkyne ring closing metathesis), a more robust route toward the desired macrocycle was sought. A sequential construction of an acyclic trimer employing cross- coupling reactions was expected to overcome the unwanted oligomerization encountered in the case of the earlier metathesis approaches. The closure of the trimer would be accomplished via the intramolecular McMurry reaction or alkene metathesis. An optimized synthesis of the solubilized dibenzo[5]helicene and its derivatives was developed. These compounds served as proposed building blocks of the acyclic trimer. Both Heck and Suzuki- Miyaura couplings used for the preparation of the acyclic trimers provided mixtures containing the desired trimers but the Suzuki-Miyaura reaction proved to be much more efficient. However, the solubility of the trimers turned out to be very low, making the separation of the pure products from the mixture impossible and seriously limiting the further synthetic progress. Only alkene metathesis of the corresponding divinyltrimer was accomplished and despite a low solubility of the starting material, the MS analysis of the...
Synthesis and properties of complex π-electron systems with helical chirality
Houska, Václav ; Stará, Irena (advisor) ; Machara, Aleš (referee)
Planar shape-persistent macrocycles have been known for a long time and are routinely synthesized today. Non-planar 3D structures, however, still remain challenging synthetic targets in many cases. The objective of this Thesis was to develop a synthetic route to shape-persistent macrocycles containing dibenzo[5]helicene or its derivatives as structural units employing alkene and alkyne metathesis. The Introduction focuses on various methods of the macrocycle synthesis, on alkyne metathesis, and synthesis of helicenes is shortly reviewed as well. Then, the first part of Results and discussion describes the synthesis of 3,16-dichlorodibenzo[5]helicene and its derivatives. In the second part, the macrocycle synthesis from these dibenzohelicenes is discussed. The Experimental part provides a detailed description of performed experiments along with characterization of all new compounds prepared.
Commuting across border in region Sumava-Bayerwald
Houška, Václav ; Kotýnková, Magdalena (advisor) ; Nováček, Jan (referee)
Diplomová práce se zabývá vlivem pendlování za prací v regionu Šumava. Snaží se postihnout, jak ovlivňuje každodenní dojíždění českých pracovníků za prací přes hranice do Německa trh práce. První kapitola vysvětluje nabídku a poptávku po práci a trh práce a v druhé kapitole se zaměřuje na specifika, kterými se trhy práce vyznačují. Pendlování představuje určitý typ migrace obyvatel, proto se ve třetí kapitole definuje migrace, typy migrace a pendlování za prací. Čtvrtá kapitola popisuje dvojí pohled Evropské unie na diskriminaci, kdy jí na jedné straně zakazuje a omezuje, ale na druhé straně jí povoluje na trhu práce. Zkoumaný region tvoří jeden přírodní celek složený ze dvou rozdílných ekonomických jednotek, které jsou charakterizovány v páté kapitole z hlediska polohy, zaměstnanosti, obyvatelstva atd. Závěrečná kapitola analyzuje pendlování za prací na základě dotazníků od samotných pendlerů a od úřadu práce.
Geographic Information Systems
HOUŠKA, Václav
This work is aimed at public geographical data resources in the Czech Republic and their usage in geographical information systems. The introduction is focused on basic notions of GIS, especially on particularities of GIS used for support of utility operation. The rest of the work deals with an analysis and design of specific solution of the GIS access to external data resources including OGC web services.

See also: similar author names
6 HOUŠKA, Václav
1 Houška, Vladimír
3 Houška, Vojtěch
6 Houška, Václav
Interested in being notified about new results for this query?
Subscribe to the RSS feed.