Národní úložiště šedé literatury Nalezeno 7 záznamů.  Hledání trvalo 0.00 vteřin. 
Preparation and Physicochemical Properties of [6]Helicenes Fluorinated at Terminal Rings.
Církva, Vladimír ; Jakubík, Pavel ; Žádný, Jaroslav ; Vacek, J. ; Strašák, Tomáš ; Hrbáč, J. ; Císařová, I. ; Storch, Jan
Two fluorinated helicenes, tetrafluoro[6]helicene and octafluoro[6]helicene were prepared photochemically and their physicochemical and optical properties were investigated. A separation of racemic tetrafluoro[6]helicene into individual enantiomers (P and M) was performed and the racemization barrier was determined. Crystal structures of major synthetic products including individual enantiomers of tetrafluoro[6]helicene were determined showing the replacement of π-π and CH-π interactions by CH-F interactions with increasing fluorine substitution. DFT calculation were performed to get an insight into the charge distribution and HOMO-LUMO gap.
Plný tet: SKMBT_C22018110615054 - Stáhnout plný textPDF
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Chiral Carbon-rich Materials – From Single Molecule to Functional Layers.
Žádný, Jaroslav ; Storch, Jan ; Strašák, Tomáš ; Krbal, M. ; Hrbáč, J. ; Vacek, J.
Comprehensive study of two different carbon-rich materials properties – [6]helicene and 1-butyl-3-(2-methyl[6]helicenyl)imidazolium bromide – and their thin films is presented. Because of different solubility, diverse preparation approaches had to be employed – electropolymerization and spin-coating. Spectroscopic and electrochemical properties were investigated along with examples of their practical use as detectors of biomolecules (e.g. DNAs). A high application potential of helicene-based carbon-rich materials in development of new optoelectronic devices is demonstrated.
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Application of Cyclopentenediones for Preparation of Permselective Layers.
Vacek, J. ; Hrbáč, J. ; Matějka, P. ; Storch, Jan
In this contribution, we report that electrooxidation of PCD, phenolic cyclopentenedione, 2,2'-bis[4,5-bis(4-hydroxybenzyl)-2-(4-hydroxyphenyl)-cyclopent-4-ene-1,3-dione] results in the formation of stable films with permselective properties on metal and carbon surfaces. The electropolymerization process proceeds in neutral and alkaline aqueous medium at potentials higher than +0.6 V (vs. Ag/AgCl/3M KCl). The PCD polymer prepared was characterized by electrochemical methods, quartz crystal microbalance and optical spectroscopy techniques. The PCD film can be used for electrode coating and preparation of an anti-interference barrier. Thus, we performed SAR study which could open the door to developing novel functional films and electrochemical tools for bioactive compounds sensing.\n
Plný tet: MEM20140001 - Stáhnout plný textPDF
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Potential-driven On/Off Switch Strategy for the Electrosynthesis of [7]Helicene-derived Polymers.
Žádný, Jaroslav ; Storch, Jan ; Strašák, Tomáš ; Církva, Vladimír ; Hrbáč, J. ; Fekete, Ladislav ; Pokorný, Jan ; Bulíř, Jiří ; Vacek, J.
3-([7]H elicen-9-yl)-thiophene hybrid monomer was electrooxidized in acetonitrile by cyclic voltammetry with anodic potential limits of +1.5 V or +2.5 V, resulting in a conductive and non-conductive polymer, respectively. The electrochemical findings were supplemented by microscopy investigations; UV-Vis, fluorescence and vibrational spectroscopies, ellipsometry measurements and computational chemistry. The electrodeposited polymers could be used for the further development of materials applicable in organic electronics and sensing technologies.
Plný tet: SKMBT_C22017111612582 - Stáhnout plný textPDF
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A Short Overview of the Electrochemistry of Helical Polyaromatics.
Vacek, J. ; Hrbáč, J. ; Zatlouklová, M. ; Storch, Jan
Here we describe the electrochemical behavior of a group of polyaromatics designated helicenes. These compounds are finding many applications in optoelectronics, catalysis and chiral separation. Thus it is important to investigate the electrochemical and optical behavior of helicenes with respect to improving their application potential and our knowledge of strategies for their surfaces immobilization. Electrochemical analyses were performed in acetonitrile and in aqueous media with glassy carbon and indium tin oxide electrodes. Specifically, [n]helicenes and their salts 1-buty1-3-(2-methy1[6]heliceny)-immidazolium bromide and 3-([7]helicene-9-y1)thiophene were investigated, the application of acquired electrochemical data is disussed, especially in terms of optoelectronics and the construction of semi-conductive devices.
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Viz též: podobná jména autorů
2 Hrbáč, Jindřich
1 Hrbáč, Jiří
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