Metal-mediated molecular materials at the nano- and mesoscale
The synthesis of materials via self-assembly is a powerful bottom-up approach for assembling matter from subnanometer up to micrometer scales. This methodology involves the spontaneous and reversible organization of small molecules to create larger structures driven by non-covalent interactions such as hydrogen bonding, hydrophobic forces and metal-ligand coordination interactions. In this dissertation we developed the synthetic methods to generate materials at the nano- and meso-scale using coordination-directed strategies for molecular self-assembly in solid-state and in water. In addition, we produced materials with a modular increased complexity with potential applications in advanced technologies and medicine. Molecular materials in the solid-state were engineered using the coordination directed approach by synthesizing organic ligands with well-defined geometries and symmetries that self-assembly with transition metals in aprotic media into supra-molecular arrays. These structures were crystallized and characterized by techniques such as X-ray Crystallography, Multi-Nuclear Magnetic Resonance (NMR), Mass Spectrometry (MS), Infrared (IR) and Ultraviolet-Visible (UV-vis) Spectroscopies. Potential application as hydrogen storage systems was evaluated using 2H NMR spectroscopy. Coordination-directed molecular materials that self-assembly in water were achieved by combining coordination capable amphiphilic molecules and designing their chemistry so that they can rearrange in water to produce different lyotropic phases. We characterized these materials using Extended X-ray Absorbance Fine Structure Spectroscopy (EXAFS), Dynamic Light Scattering, Atomic Force Microscopy (AFM), Transmission Electron Microscopy (TEM), Optical Microscopy and X-ray Photoelectron Spectroscopy (XPS). The new class of metallo-liposomes was used as a DNA delivery system and demonstrated to be effective for the transfection of pEGFP-N1 plasmid into HEK 293-T cells. Modular molecular materials were produced by integration of other components to the coordination assembles. We developed functional protein-anchoring systems and coordination polymer-carbon nanotubes (CNT) composites to illustrate this concept. The new materials exhibit programmable and modular properties that will increase our understanding of functional synthetic structures at the nano- and mesoscale.
Arroyo, Itzia Zoraida, "Metal-mediated molecular materials at the nano- and mesoscale" (2007). ETD Collection for University of Texas, El Paso. AAI3262913.