Seminars

DEPARTMENT OF CHEMISTRY, SEOUL NATIONAL UNIVERSITY.

Regulated Equilibria and Compartmentalization in Dynamic Combinatorial Libraries

February 14, 2014l Hit 412
Date : May 29, 2014 16:30 ~
Speaker : Prof. Ognjen Miljanic (University of Houston)
Location : Rm.103, Bldg.25-1

Date : 2014. 5. 29, 4:30 PM Place : Int"l conf. room, Bldg.25-1 -Abstract- The objective of my group"s research is to develop selective and high-yielding synthetic methods that create functional molecules and materials starting from complex mixtures of precursors, and to subsequently study and utilize these newly prepared compounds. Traditional synthetic chemistry shies away from complex mixtures. Instead, pairs of compounds are typically reacted in isolation, to avoid competing reactions that would create undesired products. This reductionist approach is necessary because most of synthetically useful reactions proceed under kinetic control, resulting in stable product compounds which do not revert back to starting materials. When an undesired product is formed, it cannot be recycled and is effectively lost to the reaction. In contrast, in thermodynamically controlled synthetic protocols, both the desired and the undesired products remain in chemical equilibrium with their precursors. In such cases, selective synthesis of highly stabilized compounds can be accomplished even in complex mixtures with many members, as equilibration ensures the free transfer of the material—and, conceptually, information—from the less stable to the more stable members of the mixture. Such dynamic combinatorial libraries (DCLs) can respond to external pressures by expressing their components that best adapt to those pressures, as stipulated by the Le Châtelier principle. My group works on three distinct but interconnected areas, all of which employ chemically dynamic constructs to achieve results that would be difficult or impossible to observe in the absence of such dynamic function. Specifically, we have developed: (a) Self-sorting synthetic protocols which can produce multiple pure compounds in high yield starting from complex DCLs; (b) Porous metal-organic frameworks (MOFs) constructed from novel perfluorinated and macrocyclic ligands and characterized by unique adsorption properties, and (c) Cross-conjugated fluorophore sensors based on benzobisoxazole and benzimidazole nuclei, which can sense a broad variety of chemical species either alone or within hybrid sensor self-assemblies with boronic acids.