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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

SELECTIVE ACTIVATION OF TERBIUM(III) AND EUROPIUM(III) LUMINESCENCEWITH TRIARYLBORON-FUNCTIONNALIZED CARBOXYLATE LIGANDS. AND LUMINESCENT 8-HYDROXYQUINOLINE DIPICOLYLAMINE COMPLEXES AS SENSORS FOR ZINC(II).

Varlan, MARIA 12 September 2012 (has links)
The impact of a tri-substituted boron moiety on the chelate sensitization of Tb(III) and Eu(III) lanthanide luminescence and their resulting photophysical properties was investigated. Two triarylboron-functionalized carboxylate ligands 1 and 2 and their respective Tb(III) and Eu(III) complexes, 1Tb, 2Tb, 1Eu and 2Eu were synthesized and fully characterized. The photophysical properties of these compounds were studied and it was established that these three-coordinate boron ligands are highly effective in selective activation of Tb(III) and Eu(III) luminescence yielding high efficiency green and red luminescence, respectively. Potential applications of these triarylboron-functionalized chelate Tb(III) and Eu(III) complexes as luminescent sensors for dipicolinic acid (DPA), a biomarker for anthrax spores, as well as small anions such as F- and CN- in organic solution were examined by titration experiments using UV-Vis absorption and fluorescence emission measurements. Further studies were carried out into the application of the lanthanide complexes as solid substrate luminescent sensors for the same analytes. Furthermore a novel zinc-binding compound, composed of both an 8-hydroxyquinoline fluorophore and a dipyridyl metal binding site, was designed for application as a luminescent sensor for Zn(II), due to the recent link between the metal ion and certain high-profile neurological conditions such as Alzheimer’s and epilepsy. The target ligand compound 1-OH was successfully synthesized and characterized using UV-Vis, Fluorescence and NMR spectroscopy. Further studies of the ligand are recorded by studying the effects of the addition of both four-coordinate boron and tris(8-hydroxyquinolinato)aluminum active sites to the 1-OH molecule frame. The four compounds’ abilities in luminescent Zn(II) detection in organic media were examined by titration experiments with Zn(II) using UV-Vis absorption and fluorescence emission measurements. / Thesis (Master, Chemistry) -- Queen's University, 2012-09-11 16:36:17.004
2

Synthesis, functionalization and characterization of zirconium - and hafnium based metal-organic frameworks and improved impact of modulators on water adsorption, catalytic and sensor applications

Drache, Franziska 12 June 2018 (has links) (PDF)
The object of this thesis is to get a deeper understanding of the role of modulator agents in the synthesis of Zr- and Hf-based metal-organic frameworks (MOFs) and their impact on framework properties, such as textural properties, stability, hydrophobicity, and catalytic activity. For this purpose, MOFs are investigated that are built up by the commercially available linker 2,5-thiophenedicarboxylate and the Zr6(µ3-O)4(µ3-OH)412+ cluster. With proper choice of the modulator a new structure, namely DUT-126 (DUT = Dresden University of Technology), could be presented in the course of this work, besides the already known polymorphs of DUT-67, DUT-68 and DUT-69. Furthermore, DUT-67 is chosen as a model structure to functionalise the metal cluster of the framework by exchanging the modulator post-synthetically with hydrophobic fluorinated monocarboxylic acids. With the introduction of these fluorinated molecules, the surface polarities and the stability against water removal can be tuned. In addition, the metal clusters of DUT-67 were modified with a complete removal of the pristine modulator molecules by means of an acidic treatment in order to generate open metal sites that can function as Lewis acid sites. The suitability of DUT-67 and its acid treated analogues as heterogenous catalyst was tested on the Meerwein-Ponndorf-Verley reduction of cyclohexanone. Furthermore, the UiO-67 analogue DUT-122, which contains the luminescent linker 9-fluorenone-2,7-dicarboxylate, was tested as sensor material to detect solvent vapours. It could be shown that DUT-122 is sensitive to various solvent vapours, which induce photoluminescent shifts and intensity changes of the fluorescence emission profile depending on the polarity and the functionality of the respective solvent.
3

Synthesis, functionalization and characterization of zirconium - and hafnium based metal-organic frameworks and improved impact of modulators on water adsorption, catalytic and sensor applications

Drache, Franziska 26 April 2018 (has links)
The object of this thesis is to get a deeper understanding of the role of modulator agents in the synthesis of Zr- and Hf-based metal-organic frameworks (MOFs) and their impact on framework properties, such as textural properties, stability, hydrophobicity, and catalytic activity. For this purpose, MOFs are investigated that are built up by the commercially available linker 2,5-thiophenedicarboxylate and the Zr6(µ3-O)4(µ3-OH)412+ cluster. With proper choice of the modulator a new structure, namely DUT-126 (DUT = Dresden University of Technology), could be presented in the course of this work, besides the already known polymorphs of DUT-67, DUT-68 and DUT-69. Furthermore, DUT-67 is chosen as a model structure to functionalise the metal cluster of the framework by exchanging the modulator post-synthetically with hydrophobic fluorinated monocarboxylic acids. With the introduction of these fluorinated molecules, the surface polarities and the stability against water removal can be tuned. In addition, the metal clusters of DUT-67 were modified with a complete removal of the pristine modulator molecules by means of an acidic treatment in order to generate open metal sites that can function as Lewis acid sites. The suitability of DUT-67 and its acid treated analogues as heterogenous catalyst was tested on the Meerwein-Ponndorf-Verley reduction of cyclohexanone. Furthermore, the UiO-67 analogue DUT-122, which contains the luminescent linker 9-fluorenone-2,7-dicarboxylate, was tested as sensor material to detect solvent vapours. It could be shown that DUT-122 is sensitive to various solvent vapours, which induce photoluminescent shifts and intensity changes of the fluorescence emission profile depending on the polarity and the functionality of the respective solvent.

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