Host-Guest Properties of Metal-Assembled Cage Complexes. Separations chemistry and enzymatic catalysis are just two of the many fields of chemistry that rely on molecular recognition. Separating compounds and selectively catalyzing a reaction are facility by interactions between two molecules. Our introduction into the field of metal-assembled host-guest complexes came with the discovery in our group that two synthesized cup shaped molecules can be brought together by metal ions into a capsule molecule. We have formed these metal-resorcinarene complexes with various metal ions such as iron, cobalt and copper and are pursuing with interest the selective encapsulation abilities of these metal complexes. We are also exploring larger host compounds and their ability to encapsulate water contaminants. Students working on this project learn to synthesize and characterize organic and inorganic compounds. Student also are involved in applying the metal complexes to areas of separations of contaminants from water and metal ion promoted catalysis of substrates.

     Design and Synthesis of Materials. Porous materials, most notably zeolites, are used extensively in catalysis and separations. New types of porous materials, ones based on metal ions and organic compounds, have emerged and are receiving attention due to their catalytic and separations abilities. Our research efforts have began to focus on the synthesize and characterize of new porous metal-organic materials based on resorcinarene cages. We have found that the pore and channel sizes can be changed by changing the counter cations. Also, the adsorption ability of the material changes when the material's counter cation is exchanged. Current research pursuits involve the forming of porous materials with pores of greater size, nonpolar character, and surrounded by transition metals. To synthesize these materials, we are changing the resorcinarenes and the cations. This research gives experience in organic synthesis, inorganic synthesis, and materials characterization. Students working on this research use NMR, ICP, IR, X-ray, XRD, and TGA to investigate the materials.

     Metal Complexes Used in Separations. Another related area of research we are pursuing is the application of metal complexes in separations, such as capillary chromatography and liquid membranes. In collaboration with Dr. John Lamb, students in our groups synthesize metal complexes and use them in chromatography and membranes to separate biomolecules or anions.

     Nanocrystal Synthesis. Particles with diameters in the nanometer range are being studied for their semiconductor and energy transfer properties. Members of our group synthesize nanoparticles, made of CdSe or Au, and with physicists, investigate the light absorption and emission properties as well as the electronic properties of the nanoparticles. We are investigating ways to link nanoparticles and to make small electron transfer materials. Students on this project synthesize new nanoparticles and help characterize them by NMR, TEM, ICP, and Uv-vis.