Events Calendar

CH 633 Seminar - Omar Farah, Tanner Rookard

Farah:
Title: Origins of Regiocontrol in Radical Thiol-ene Reactions of gem-diFluoro Alkenes
Gem-difluoro substituents are desirable in pharmaceuticals due to their ability to increase
the solubility and membrane permeability of drugs. Recently, Altman and coworkers of
Purdue University discovered that gem-difluoro thioethers can be obtained from radical
thiol-ene reactions of difluorinated alkenes. However, poor regioselectivity during the
thiol addition limits the reaction scope to gem-difluoro vinylbenzene. In order to
understand how regiocontrol is manifested in these reactions, density functional theory
(DFT) studies were carried out. DFT results reveal that the regioselectivity of radical
thiol-ene reactions are almost exclusively influenced by the substitution patterns of the
thiol and the gem-difluoro alkene. Aryl substitutions on the gem difluoro-alkene
dominate the reaction selectivity by the virtue of the benzylic stabilization, giving rise to
exclusive linear products. Aryl substitution on the thiol radical also leads to a smaller
preference for the linear. Alkyl substitutions, on the other hand, leads to branched
products, predominantly due to steric effects. This work gives greater predictability in
thiol-ene reactions and highlights the strong inherent chemoselectivity by the substrates
of this reaction.

Rookard: 
Title: ‘MOP’ping Up Ammonia
Metal-organic polyhedra (MOPs) are discrete molecules comprised of a metal and interconnecting ligands. The resulting MOP structures are porous cages (Figure 1a), and to date, they have shown great promise toward gas capture. Ammonia is a hazardous gas that is produced in enormous quantities for use in fertilizers. In this talk, I will present the use of three functionalized rhodium (Rh)-based MOPs for ammonia capture. Activation of MOPs leads to the generation of open Rh sites which are thought to be responsible for the efficient and irreversible ammonia uptake (Figure 1b). To regenerate the MOPs and therefore recover their ammonia adsorption capacities, we immersed the ammonia-loaded materials in an acidic solution which yielded up to 96% regeneration of the adsorption capacity (Figure 1b). The ammonia uptake of these Rh-MOPs rivals or exceeds that of many of the previously reported materials.
 

Thursday, December 2 at 4:30pm

Linus Pauling Science Center, 402
2900 SW Campus Way, Corvallis, OR 97331

Event Type

Lecture or Presentation

Event Topic

Research

Audience

Faculty and Staff, Student, Alumni, Industry Partner, Online

County

Benton

Organization
College of Science, Department of Chemistry
Contact Name

Luanne Johnson

Contact Email

luanne.johnson@oregonstate.edu

Contact Phone

5417376706

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