Surfactant Transition Metal Chelates

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With this renewal award the Organic and Macromolecular Chemistry Program supports the work of Dr. David A. Jaeger in the Department of Chemistry at the University of Wyoming in Laramie. The proposed research involves the synthesis, isolation, and characterization of two series surfactants based on Co(III) chelates, using ligands related to ethylenediamine tetraacetic acid and nitrilotriacetic acid. The structures of the surfactants will be established using nuclear magnetic resonance spectroscopy (NMR of 1H, 13C and 59Co) , UV/vis, FT-IR, and single crystal x-ray diffraction. Aggregate morphologies in water will be characterized by Krafft temperature and measurements of critical aggregation concentration, NMR, dynamic light scattering, differential scanning calorimetry, optical microscopy, and electron microscopy. Monolayers on water will be characterized by surface pressure-area isotherms. Of particular interest will be the dependence of aggregate morphology and monolayer behavior on surfactant stereochemistry.Dr. Jaeger's research involves surfactants - surface active agents that prefer to be at the interface between phases (such as air and water) - in which binding of chelating ligands to cobalt +3 ions plays an important role in fixing the structure of the resulting surfactant molecule, and in giving different properties from what they would be in the absence of metal binding. By systematically changing the ligand structure, he hopes to understand the factors controlling the structure and properties of the resulting surfactant. This new class of molecules might have several applications including redox-switched systems, site-specific protein and DNA cleavage catalysts, and catalytic hydrolysis of amides and esters. The work is expected to provide valuable training for the students doing the work because of the variety of experiments and instruments involved.