Fundamental studies of molecularly imprinted polymers and atropisomers.

摘要

Three distinct research goals governed the work presented herein. First, methods for characterizing the binding properties of molecularly imprinted polymers (MIPs) were investigated and reported upon. We found that although the heterogeneous nature of these materials produced highly concentration-dependent adsorption behavior, there was a dearth of analytical methods that had been previously applied that accommodated this feature. The merits of the Freundlich Isotherm in describing MIP binding properties was evaluated and found to be useful under most conditions tested. Based on this and other previous work, we also presented a more qualitative approach to analyzing MIPs using log-log isotherms. The advantage of this method was that the most important properties to a researcher, the polymer's capacity and selectivity, were easily evaluated through a visual inspection of the log-log isotherm. This approach avoided the necessity of assuming and applying a particular binding model to the isotherm before a determination of the material's utility could be assessed. When this analysis was applied to a MIP for (+)-cinchonine in aqueous and organic media, the results indicated that diastereoselectivity was achieved under both conditions.; Second, host-guest interactions between a N,N'-diaryl naphthalene diimide atropisomer and a variety of organic molecules were investigated to determine the relationship between the strength of the complex formed and the rotational barrier about a Caryl-Nimide bond. We found that the barrier was sensitive to both the identity and the concentration of guest which afforded fine control over the rotational freedom of the system. This control was exploited in the design of a reversible molecular brake.; Finally, two laboratory investigations based upon the these research projects were developed for use in undergraduate chemistry courses. The first was designed for a polymer course where the students investigate the binding properties of an ethyl adenine-9-acetate MIP compared to a control polymer. The second was written for an introductory organic chemistry course to enhance the students' ability to measure and contextualize the meaning of the rotational barrier of a N-arylimide. Both investigations were designed to emphasize essential chemistry concepts and technical skills without requiring expensive equipment or extensive time to complete.