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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

Activation and Reduction of Carbon Dioxide Using Bis-Mesityl Imidazole Ylidene

Wilson, Solita 31 May 2019 (has links)
No description available.
2

An Unexpected “Bodipy-Like” Dipyrromethene With pH Dependent On/Off Fluorescent Properties

Owen, Spencer Austin 13 July 2022 (has links)
No description available.
3

The rate inhibiting effect of water as a product on reactions catalysed by cation exchange resins : formation of mesityl oxide from acetone as a case study

Du Toit, Elizabeth Louisa 27 February 2004 (has links)
It is known that when water is a product in reactions catalysed by cation exchange resins, it inhibits the reaction rate much more than predicted by the reverse reaction or dilution effects. In this work the inhibiting effect is ascribed to the preferential association of the catalytically active sites with water. In the derivation of the kinetic model, a Freundlich type adsorption isotherm was used to quantify the number of sites occupied by water. This is combined with a power law expression for the reaction rate. The resultant expression can accurately predict the reaction rate for various initial concentrations of water and mesityl oxide. Even when water was initially added to the reaction mixture, this model still gave an absolute average error of 6.5% compared to a 54.6% error when the same approach was followed but with the more popular Langmuir isotherm to describe site deactivation. The kinetic expression previously proposed for this reaction system by Klein and Banchero also failed when water was added to the reaction mixture and gave an average error of 71.1%. The procedure used to derive the model is therefore suggested for all cation exchange catalysed reactions where water is one of the products. / Dissertation (MSc)--University of Pretoria, 2005. / Chemical Engineering / unrestricted
4

Studies on the Reactivity of a Bis–Mesityl Imidazolyl Carbene Intermediate toward Carbon Dioxide and Stability of the Resulting Carboxylate

Ka, Seon Young 23 August 2019 (has links)
No description available.
5

Blue phosphorescent nitrile containing C^C* cyclometalated NHC platinum(II) complexes

Tronnier, Alexander, Metz, Stefan, Wagenblast, Gerhard, Muenster, Ingo, Strassner, Thomas 26 November 2019 (has links)
Since C^C* cyclometalated Pt(II) complexes with N-heterocyclic carbene (NHC) ligands have been identified as potential emitter materials in organic light-emitting devices (OLEDs), very promising results regarding quantum yields, colour and stability have been presented. Herein, we report on four nitrile substituted complexes with a chelating NHC ligand (1-(4-cyanophenyl)-3-isopropyl-1H-benzo[d]imidazole or 4-(tert-butyl)-1-(4-cyanophenyl)-3-methyl-1H-imidazole) and a bidentate monoanionic auxiliary ligand (acetylacetone or dimesitoylmethane). The complexes have been fully characterized including extensive 2D NMR studies (COSY, HSQC, HMBC, NOESY, 195Pt NMR), three of them also by solid-state structures. Photophysical measurements in amorphous PMMA films and pure emitter films at room temperature reveal the impact of the mesityl groups in the auxiliary ligand, which led to a significant increase of the quantum yield, while the decay lifetimes decreased. The electron withdrawing nitrile groups shift the emission towards blue colour coordinates.

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