Fall 2020 Seminars
Zoom Webinar/Seminar at 3:00-3:45 PM Est and Questions 3:45-4:00
|Date||Speaker||Home Institution||Host||Type of Chemistry|
|September 4, 2020||Oleg Ozerov||Texas A&M Univeristy||John Lee||Inorganic|
|September 18, 2020||Keenan Dungey||UTC||John Lee||Inorganic|
|September 25, 2020||Missy Mathis||Aegis Sciences Corporation||John Lee||Industry|
|October 9, 2020||Paige Castleman||The University of Memphis||Gretchen Potts||PhD candidate|
Dr. Oleg V. Ozerov (Texas A&M University)
New Chemistry With Boron And Aluminum In Pincers
Abstract: Pincer complexes of late transition metals have been widely used in studies of stoichiometric and catalytic activation of carbon-hydrogen and carbon-heteroatom bonds. Our group recently demonstrated the impressive potential of Ir pincer complexes in C-H bond borylation of terminal alkynes and arenes. Studies of transformations that involve metal-boryl intermediates where the boryl group originates from a reagent have led us to consider alternative approaches to bond activation that incorporate boryl (and aluminyl) donors into supporting pincer ligands. We have discovered that activation C-H and other bonds of heteroatom-containing substrates is possible with unique selectivities relying on coordination of the heteroatom to the metal-bound boryl donor. Current efforts are focused on the discovery of new reaction pathways and potential catalytic applications.
Dr. Keenan E. Dungey (University of Tennessee at Chattanooga)
Nanoparticles for Environmental Remediation
Abstract: Nanotechnology, the manipulation of matter at the nanometer scale, produces new effects not seen in bulk materials. For example, nanoparticles are effective catalysts due to their large surface area to volume ratios. Due to these enhanced properties, nanoparticles are being explored for environmental remediation applications. Our approach to nanotechnology is to use environmentally benign materials, prepared using green chemistry principles. In particular, we are using Zero-Valent Iron Nanoparticles (nZVI) to enhance bacterial denitrification in agricultural soils. Excess nitrates in agricultural fields are pollutants and should be reduced to prevent degradation of environmental waters (lakes, rivers, oceans). In this experiment, nZVI was prepared in a sustainable manner using biochar from Milo seed (Sorghum bicolor) and was impregnated with iron (III) salts; zero-valent iron was produced by carbothermal reduction. The nZVI was added to low-nutrient bacterial media, sodium nitrate, and inoculated with Pseudomonas aeruginosa. Results indicate that the denitrification rate was greatest in the mixture containing both nZVI and bacteria. This was observed by monitoring the nitrate concentration over a seven day period using ion chromatography. The biochar-supported nZVI were further characterized by powder X-ray diffraction, scanning probe microscopy, and transmission electron microscopy.
Ms. Missy Mathis (Aergis Science Corporation)
Aegis Sciences Corporation is a forensic toxicology and healthcare company that was founded in 1990 and located in Nashville, TN. Aegis provides science-driven drug testing and consulting services. The healthcare laboratory is dedicated to making a difference in people’s lives by offering drug testing that provides information about patients’ medication adherence, which aides healthcare providers in the treatment and care of their patients. In addition to medication compliance, Aegis offers sports testing, substance abuse detection, and drug-drug interaction testing in urine, oral fluid, or blood specimens. Currently, Aegis has nearly 1,000 team members dedicated to serving our clients, which includes healthcare providers, professional and amateur sports organizations, university athletic departments, and others.
Ms. Paige Castleman (The University of Memphis)
Collaborative Computational Efforts: Benchmarking for Orphan G Protein Coupled Receptor Ligand Discovery
Abstract: G-Protein Coupled Receptors (GPCR) comprise a superfamily of over 800 integral membrane proteins with roles in cellular biochemistry and pathophysiology. With approximately 35% of FDA approved pharmaceuticals targeting GPCR and ~10% of GPCR being orphans that lack known endogenous activators, ligand identification for orphan GPCR is of utmost importance to enable additional work that will elucidate the role of orphan GPCR in normal human physiology and disease. Two computational methods used in ligand identification studies, homology modeling and pharmacophore modeling, have been benchmarked during lab standard operating procedure development. GPCR ligand interaction studies often have a starting point with either crystal structures or homology models. The majority of GPCR do not have experimentally-characterized 3-dimensional structures, so homology modeling is a good structure-based starting point. Homology modeling is a widely used method for generating models of proteins with unknown structures by analogy to crystallized proteins that are expected to exhibit structural conservation. Traditionally, homology modeling template selection is based on global sequence identity and shared function. However, after further examination, high sequence identity localized to the ligand binding pocket was shown to produce better models for examination of protein-ligand interactions. Additionally, ligand-based pharmacophore modeling, an in silico method that uses comparisons of known ligand structures to generate models relating positions of common functional groups in three dimensions, in combination with database mining is frequently used to identify candidate ligands for subsequent in vitro and in vivo validation. Another benchmark study examined the potential to develop functionally-biased pharmacophores using ligands of same (or mixed) function with current datasets and methods, and established a pharmacophore development protocol for the identification of novel GPCR ligands. The results of these computational benchmark studies have been/will be used to guide the ligand identification efforts of multiple orphan GPCR within our lab group.