Student Poster Presentation # 5( Session 1)
Highly Efficient Recycle of Water Soluble NHC-Ru Catalyst via Host- Guest Interaction
Student Poster Presentation # 5( Session 1)
Highly Efficient Recycle of Water Soluble NHC-Ru Catalyst via Host- Guest Interaction
Cheoljae Kim and Hoyong Chung Department of Chemical and Biomedical Engineering, Florida State University
Abstract
Host-guest interaction is one of the defining concepts of supramolecular chemistry which describes an idea of molecular recognition and interactions through non-covalent bonding between two or more molecules or ions. Based on the specific recognition of host molecules towards guest molecules, host-guest chemistry has been widely studied for drug carriers, dye encapsulation, nanoreactors, recovery of catalysts, and etc. Cyclodextrin( CD) is one of a well-known host molecule, and its hydrophobic cavity provides a strong binding interaction with azo benzenes and adamantyl group via van der Waals force in water solution. Using this property, we have newly developed a highly recoverable Hoveyda-Grubbs 2 nd generation catalyst bearing extended ethylene glycols and adamantyl group on NHC ligand. In particular, extended ethylene glycol group provides a highly water soluble property for a homogenous catalytic reaction in water as well as a recovery of catalysts from organic solution by extraction with water. The adamantyl group combines with β- CD in aqueous solution, and this host-guest complex leads an efficient heterogeneous recovery of entire ruthenium catalyst after homogeneous reaction. The new recoverable NHC ligand will be extended to other transition metal catalysis( Pd, Cu), organocatalysis( ring-opening polymerization of lacides), flat surface modification, and medicinal application( anti-cancer agent, anti-infection agent).
Figure 1. Our Hoveyda-Grubbs 2 nd generation catalyst
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