UNT Theses and Dissertations - 2 Matching Results

Search Results

Design, Synthesis and Screening of Homoleptic and Heteroleptic Platinum(ii) Pyridylazolate Complexes for N-type Semiconducting and Light-emitting Devices

Description: A series of heteroleptic and homoleptic platinum(II) complexes has been synthesized and characterized towards their use in thin film devices such as organic light-emitting diodes (OLEDs) and organic thin film transistors (OTFTs). Pyridylpyrazolate- and pyridyltetrazolate-containing ligands were selected due to their structural rigidity and ease of functionalization. Single-crystal x-ray diffraction studies of two selected heteroleptic complexes show strong aggregation with preferential stacking into vertical columns with a varying degree of overlap of the neighboring square planar molecular units. It is shown that the close proximity of the molecules to one another in the stack increases semiconducting character, phosphorescence quantum yields, and shorter radiative lifetimes. The potential for these materials towards incorporation into high-efficiency doping free white OLEDs (DFW-OLEDs) for solid-state lighting and display applications has been realized and will be expanded upon by present and future embodiments of materials in this thesis.
Date: August 2012
Creator: Oswald, Iain William Herbert
Partner: UNT Libraries

Group 10 Catalyzed Olefin Hydroarylation

Description: Alkyl-arenes are important industry feedstock chemicals that are used as solvents, pharmaceutical precursors, and polymer monomer units. One alkyl-arene, ethylbenzene, is the main focus of this dissertation, and is produced in the million ton a year scale. As alkyl-arenes are important commodity chemicals, catalytic olefin hydroarylation is a lucrative alternative for their production rather than Friedel-Crafts alkylation or various coupling reactions that have lower atom economy, require strong acids, or are energetically demanding. Currently catalytic olefin hydroarylation still suffers from decomposition pathways of the active catalytic complexes, side reactions that lead to waste products, and unfavorable activation barriers, which represent high temperature and pressure. Modifications to the catalytically active system bipyridine platinum(II) (bpyPtII), through computational methods, are explored herein. The work presented here investigates catalytic olefin hydroarylation in order to mitigate the aforementioned difficulties. Included in this study are changes to the electronic profile of the supporting ligand, bpy, through the addition of electron withdrawing or electron donating R groups (methoxy, nitro), definite ligand replacements such as bpy to hydridotris(pyrazolyl)borate (Tp), changes in metal oxidation (II to IV), and replacing the metal center from Pt to Ni. Nickel was selected as a possible alternative to platinum as it is more Earth abundant reducing the monetary requirement for the catalyst. In addition to having a different catalytic energetic profile from platinum. Ni as expected could only facilitate single step hydrogen atom transfers due to its inability to access higher oxidations states.
Date: December 2012
Creator: Gonzalez, Hector Emanuel
Partner: UNT Libraries