Anion Recognition of Polyoxometalates
Polyoxometalates (POMs) are large, early-transition-metal oxide clusters that are widely studied owing to their catalytic and biological activity. But, because of their large size, POMs were historically outside the scope of anion recognition chemistry. Recently, however, there has been growing interest in the interactions between POMs and various organic molecules and solid supports. The Roesner group designs macrocyclic and polymacrocyclic receptors as hosts for POM guests. In these receptors, metallated crown ether moieties or protonated aza-macrocycles serve as pre-organized points of positive charge for coulombic interaction with the POM guests. By exploring new methods of immobilizing and encapsulating POMs, the Roesner group aims to increase their utility as catalysts and sensors.
Astrochemically Relevant Mineral Dust
Information about the chemistry that occurs in interstellar space comes from the interpretation of spectral signatures gleaned through observational astronomy. Observations in the submillimeter region are crucial for studying cool, dusty regions and their interpretation requires laboratory-generated spectra for comparison. To that end, the Roesner group (Illinois Wesleyan, Chemistry) has been preparing micron sized mineral dusts to be studied by the T. Perera group (Illinois Wesleyan, Physics) using a submillimeter spectrometer built for this purpose. The mineral dusts are prepared using sol-gel, microwave, or solid state methods; characterized by scanning electron microscopy, mid-IR spectroscopy, X-ray powder diffraction, and X-ray-fluorescence spectroscopy; and finally incorporated into polyethylene pellets for subsequent study using the submillimeter spectrometer.
Laboratory Projects for the Undergraduate Laboratory Curriculum
Undergraduate laboratory courses are enriched when projects involve authentic problem solving and hands-on use of research-grade instrumentation. To this end, the Roesner group has developed multi-week laboratory projects on topics including the synthesis and gas chromatography/mass spectroscopy analysis of biodiesel fuel; physical measurements of metallocenes; and the synthesis and microscopy of metal oxide microparticles with elegant morphologies.