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Molecular crystals for NLO applications - compounds of 1H-pyrazole-carboxamidine
Kohúteková, Soňa ; Němec, Ivan (advisor) ; Šloufová, Ivana (referee)
Title: Molecular crystals for NLO applications - compounds of 1H-pyrazole-carboxamidine Author: Bc. Soňa Kohúteková Department: Department of Inorganic Chemistry Supervisor: prof. RNDr. Ivan Němec, Ph.D. Abstract: The aim of this diploma thesis is preparation and characterisation of novel compounds of 1H-pyrazole-carboxamidine in consideration of their potential application in the field of nonlinear optics. This thesis is focused on preparation of crystalline salts or adducts combining 1H-pyrazole-carboxamidine with selected inorganic and organic acids. Prepared materials were characterised mainly by the means of vibrational spectroscopy and X-ray diffraction analysis. Quantum-chemical calculations were used for a prediction of nonlinear optical properties as well as for interpretation of measured vibrational spectra. Four different approaches of calculations were used for an optimisation of computing time together with accuracy of the fit of calculated and measured spectra. Finally, measurements of second harmonic generation efficiency of two powder samples with non-centrosymmetric crystal structures were performed. Key words: NLO, vibrational spectroscopy, crystal structure, quantum-chemical calculations
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Surface-enhanced Raman microspectroscopy of biomolecules and biological systems
Šimáková, Petra ; Procházka, Marek (advisor) ; Michl, Martin (referee) ; Šloufová, Ivana (referee)
The aim of this thesis was using surface-enhanced Raman scattering (SERS) microspectroscopy for the study of biomolecules and biological systems. The main probe molecule was cationic porphyrin H2TMPyP, however, other porphyrins, tryptophan and two lipids were also used. The sensitivity and reproducibility of several solid SERS substrates: (i) Au and Ag nanoparticles (NPs) immobilized via a bifunctional linker, (ii) AgNPs immobilized by drying, (iii) highly ordered Au and Ag film-over-nanosphere (FON) and (iv) Ag-coated insect wings were compared. On most of the solid substrates, the lowest detected H2TMPyP concentration was ~10-8 M. The highest sensitivity was provided by the dried drops of AgNPs/analyte mixture, where concentrations 1×10-10 M TMPyP, 1×10-5 M tryptophan, 2×10-7 M DSPC and 3×10-7 M DMTAP were detected. Nevertheless, the spectral reproducibility was decreased due to porphyrin metallation and perturbation of the lipid spectra in comparison to their Raman spectra from solution. The highest reproducibility was achieved by AuFON and Ag-coated insect wings. Finally, the AgNPs modified by PEG polymers were tested for intracellular application using HeLa cancer cells. Metallation of H2TMPyP served to probe the accessibility of PEG- AgNPs surface. The results proved that the accessibility...
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Assembling of Ag and Au nanoparticles mediated by terpyridine-based oligomers: Relationship between morphology and spectral characteristics
Prusková, Markéta ; Šloufová, Ivana (advisor) ; Procházka, Marek (referee)
This work is aimed at the preparation and morphological and spectroscopic characterization of the interphase nanocomposite (NC) two-dimensional (2D) self-assembled systems of Ag and Au nanoparticles (NPs). The NPs were functionalized with the following ligands with terpyridine end-groups: 2,2′:6′,2′′-terpyridine (tpy), 4'-(2-thienyl)-2,2':6',2''- terpyridine (T-tpy), α,ω-bis(terpyridyl)-2,2'-bithiophene (tpy-2T-tpy) and α,ω-bis(terpyridyl)- 2,2':5',2''-terthiophene (tpy-3T-tpy). The morphological analysis of transmission electron micrographs proves the preservation of the average interparticle distance in closely spaced NP pairs, independent of the ligand. The value of the total average interparticle distance increases in the order: tpy < T-tpy < tpy- 2T-tpy < tpy-3T-tpy, while the average occupied area fraction in the same order decreases. The morphological descriptors (i.e. interparticle distance and occupied area fraction) were found to correlate with the shift of the SPE (surface plasmon extinction) maxima of NCs (tpy > T-tpy > tpy-2T-tpy > tpy-3T-tpy). The results show that the shift of SPE band maximum depends on the degree of surface plasmon delocalisation rather than on the value of the average interparticle distance in closely spaced NP pairs. The smaller are the islands formed by closely...
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Application of micro-Raman spectroscopy to analysis of artworks
Váňová, Hana ; Němec, Ivan (advisor) ; Šloufová, Ivana (referee)
This thesis deals with the application of micro-Raman spectroscopy to analysis of artworks. The main topic of the thesis was to qualify, select and eventually optimize methods acceptable to identification of indigo dye in the paint layers of artworks. Selected dye was studied in various states using set of excitation lasers emitting in the visible region. There was also studied the real usage of resonance and surface-enhanced methods. The result of the thesis are the conclusions related with the suitability of particular techniques of Raman spectroscopy to identify the target pigment in the art.
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Raman Microspectroscopy in Microfluidic Devices
Peksa, Vlastimil ; Mojzeš, Peter (advisor) ; Šloufová, Ivana (referee)
Miniaturization of devices to study chemical interactions and processes in liquid samples has led to the emergence of microfluidics and construction of lab-on-a-chip systems. Present work was devoted to implementation, development and testing of microfluidic systems with detection by confocal Raman microscopy and surface enhanced Raman scattering under the conditions of training department. Several options of performing standard macroscopic measurements in microscopic scales were explored. A method for measuring thermal stability of biopolymers in microsystems with contactless detection of temperature has been designed and tested. Furthermore, possibilites for studying the SERS effect within microfluidic channels were explored. It was demonstrated that the microfluidic chips provide promising opportunity to study hydrodynamics of liquids at microscopic level and chemical reactions and kinetics.
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Vibrational modes of nucleic acids components characterized by means of variable proton-deuterium exchange
Zoul, David ; Štěpánek, Josef (advisor) ; Šloufová, Ivana (referee)
Although the nucleon acid oscillatory spectra have been studied for a long period of time, many of oscillating modes have not been properly explained regarding their geometric sensitivity and weak binding. One of the possibilities how to acquire experimental data for interpretation of theese modes is to confront oscillating spectra of isotopes. The simplest is proton - deutron exchange. When molecules dissolve in heavy water they rapidly exchange the heteroatoms, but this is simultaneous for more stages, which leads to dynamic equilibrium state among various isotope forms. Statistic analysis of temporal progression of Raman spectra give us the possibility to analyze the spectra and to obtain unique experimental data. This technique is very promising for more complex nucleon acid segments to gain more structural information. This diploma thesis represents pilot study of introduced methodics. The objective is to implement adaptation of Raman spectrometr for given types of expiments and undertake first series of measurements. The results should clarify application bounds of proposed method refering to sensitivity, time constant of incident isotope exchange, severity of read-out in comparasion of achieved accuracy of the measurement.
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