The Department of Chemistry invites you to its departmental seminar on Monday, March 2, at 4:10 p.m. in Fulmer Hall, room 438.
Dr. Orion Berryman from the University of Montana will present Fundamental Studies of Bidentate Halogen Bond Donors for Supramolecular Catalysis.
Abstract: Hydrogen bonding organocatalysts have been integral to the development of organic synthesis. Surprisingly, the advancement of other noncovalent catalysts has lagged. Halogen bonding interactions are comparable in strength to hydrogen bonding forces, yet their application has focused predominantly on crystal engineering. The polarizable and covalent nature of halogen bonding makes catalysts based on this interaction complementary to hydrogen bonding catalysts. This presentation describes two new classes of bidentate halogen bonding scaffolds that show promise as organocatalysts that activate substrates by halogen bonding. A modular catalyst synthesis has been developed that incorporates two imidazolium or pyridinium halogen bond donors linked by terphenyl or 1,3-diethynyl spacers—appropriate for forming bifurcated halogen bonds with carbonyl substrates. The strength and nature of halogen bonds between the scaffolds and anionic substrates is quantified in solution by 1H NMR titrations and in the solid state by single crystal X-ray diffraction. The activity of each catalyst is in the process of being benchmarked with Diels-Alder reactions and compared to a known hydrogen bonding catalyst. This research strives to produce a new class of catalyst suitable for carbonyl chemistry—necessitating that halogen bonding catalysis plays a crucial role in organic synthesis and asymmetric catalysis.
Contact: Chelsea (Pickett) Gao, chelsea.m.pickett@wsu.edu.