Browsing by Subject "Conducting polymer"
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Item Functional materials based on redox-active components(2010-12) Milum, Kristen M.; Holliday, Bradley J.; Cowley, Alan H.; Crooks, Richard M.; Dodabalapur, Ananth; Jones, Richard A.Conducting polymers have been extensively investigated in a wide range of applications due to their ability to achieve near metallic conductivity while possessing the flexibility and processability of traditional polymers. However, interchain and solid-state effects have made direct investigation of the polymer systems difficult. A series of systematically varied model compounds have been designed to provide detailed information about through-chain charge transport in well-defined oligothiophenes. Our design incorporates two metal binding pockets at either end of an oligothiophene bridge to investigate the interaction of redox centers and charge transport properties between conducting polymers and bound transition metal centers. Synthesis, characterization, electrochemistry, and detailed EPR investigations of this new series of oligothiophene model compounds and the analogous mononuclear compounds will be discussed herein. Conjugated polymer matrices possess a large number of available oxidation states making them an attractive choice for use as redox-active ligands. This variety of oxidation states offers a means to easily tune the amount of electron density on a metal center and consequently affect the binding of an additional ligand. Our approach utilizes conducting metallopolymers with metal complexes synthetically incorporated directly into the conducting polymer backbone. The redox-dependent properties of this class of materials and their development as small molecule storage and delivery systems have been explored utilizing a variety of novel electropolymerizable transition metal complexes. The design, synthesis, characterization, and redox-affected properties of the monomers, corresponding conducting metallopolymers, and model complexes are discussed. The tub-shaped dibenzo[a,e]cyclooctatetraene molecule undergoes a large change in geometry upon reduction to form the planar aromatic species. Herein, we seek to prepare and investigate a supramolecular assembly utilizing this redox-active molecule. In contrast to electrochemically active frameworks where redox changes occur at the metal centers, incorporation of a functionalized dibenzo[a,e]cyclooctatetraene ligand into an assembly has the potential to result in a redox-active framework. Not only would the redox-activity occur at the organic bridge, but reduction of the system should result in a large geometry change.Item Phosphorescent cyclometalated iridium(III) complexes and corresponding conducting metallopolymers(2012-05) Hesterberg, Travis Wayne; Holliday, Bradley J.; Cowley, Alan H.; Farrell, Joshua R.; Jones, Richard A.; Vanden Bout, David A.Conducting metallopolymers have been investigated for a variety of applications due to their ability to take advantage of both the mechanical processability of the polymer material, as well as the optical and electronic properties of the metal. Our project goal is to design, synthesize and characterize novel iridium(III)-containing conducting metallopolymers for use as the active layer in polymer light-emitting diodes. We have utilized thiophene functionalized ligands that can be readily electropolymerized into conducting polymer thin films and can be easily incorporated into a device structure. Iridium(III) was chosen as the metal center due to its promising photophysical properties, as similar complexes have demonstrated high luminescent quantum yields and short phosphorescent lifetimes. The coordination environment around the metal can be altered synthetically to tune the emission wavelength across the visible spectrum. The synthetic control over the polymer backbone, as well as the iridium(III) ligand environment, allowed us to independently vary each component, which has provided a variety of materials. The materials are characterized through 1H and 13C NMR, mass spectrometry, elemental analysis, electrochemistry, X-Ray diffraction and X-Ray Photoelectron Spectroscopy. The photophysical properties of the materials are studied through UVvii Visible absorption spectroscopy, UV-Vis-NIR spectroelectrochemistry and steadystate/ time-resolved emission spectroscopy.Item Synthesis of dibenzo[a,e]cyclooctatetraene based conducting polymer : a potential molecular polymer actuator(2010-12) Chou, Andrea Chengyi; Holliday, Bradley J.; Jones, Richard A.A new polymer with dibenzo[a,e]cyclooctatetraene as the actuation center and one of the thiophene derivatives, 3,4-ethylenedioxythiophene, as polymer chain is successfully synthesized. Nuclear magnetic resonance spectrum is obtained for each synthetic step. Several electrochemistry tests are done to examine the oxidation and reduction properties of the monomer and polymer. Cyclic voltammetry is used for the polymerization. Polymer is first grown on a metallic working electrode and further coated on an ITO plate. UV-Vis experiment is also done. A [pi] [arrow] [pi]* transition is observed as the primary polymer electronic absorption peak. Thickness of the polymer film is also recorded.