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September 2020

Archives for September 2020

ORI Names Campagna Interim Director of Strategic Programs

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President Randy Boyd shared some developments at the Oak Ridge Institute at UT (ORI at UT). A national search for the first executive director and vice provost of the Oak Ridge Institute at UT is underway.

Shawn Campagna
Shawn Campagna

ORNL Director Thomas Zacharia and Randy Boyd, in consultation with UT Knoxville Chancellor Donde Plowman and UT Health Science Center Chancellor Steve Schwab, have named Michelle Buchanan, ORNL deputy for science and technology, and Stacey Patterson, UT System vice president for research, as interim co-directors of ORI at UT until a director is named. Suresh Babu, a UT-ORNL Governor’s Chair for Advanced Manufacturing and Bredesen Center Director, will serve as ORI at UT’s interim education director. Shawn Campagna, UT Knoxville associate department head of chemistry and Director of Science Alliance, will serve as the interim director of strategic programs. Jean Mercer, UT Knoxville assistant vice chancellor for research and director of the office of sponsored programs, will serve as interim director of operations.

Collier at Kennesaw State University

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Graham Collier, originally from Fayetteville, North Carolina, received his BS in chemistry in 2011 from the University of North Carolina Wilmington. Upon graduation, Collier enrolled in the graduate program at the University of North Carolina at Charlotte and studied porphyrin chromophores under the direction of Michael Walter. After graduating in 2013, Collier enrolled in the chemistry doctoral program at UT with a concentration in polymer chemistry.
 
Collier’s dissertation entailed studying structure-property relationships of purine-based polymers and chromophores under the guidance of Mike Kilbey. Collier received his PhD in 2017 and began his position as postdoctoral research associate at Georgia Tech studying conjugated polymers for electrochromic under the mentorship of John Reynolds. Collier joined the faculty of Kennesaw State University as a tenure-track assistant professor of Chemistry in the Department of Chemistry and Biochemistry in fall of 2020.
 
Research in the Collier Group resides at the interface of organic, polymer, and materials chemistry. “We are interested in utilizing precise monomer synthesis to incorporate functional building blocks into polymeric materials with targeted macromolecular properties,” said Collier. “Specific interests include synthesis and characterization of conjugated polymer and molecule systems to understand how structure influences optical and electrochemical properties.”
 
Research in the Collier Research Group at KSU will involve the synthesis and characterization of organic molecules and polymers that find applicability in thin film electronics. The group will work to develop new polymers and molecules by manipulating their fundamental chemical structure to obtain targeted properties.
 
 
 
 

 

Vogiatzis Lab Published in Physical Chemistry Letters

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The Vogiatzis Lab published their work “Direct Identification of Mixed-Metal Centers in Metal−Organic Frameworks: Cu3(BTC)2 Transmetalated with Rh2+ Ions” in a collaborative piece in The Journal of Physical Chemistry Letters.

Raman spectroscopy was used to establish direct evidence of heterometallic metal centers in a metal–organic framework (MOF). The Cu3(BTC)2 MOF HKUST-1 (BTC3– = benzenetricarboxylate) was transmetalated by heating it in a solution of RhCl3 to substitute Rh2+ ions for Cu2+ ions in the dinuclear paddlewheel nodes of the framework. In addition to the Cu–Cu and Rh–Rh stretching modes, Raman spectra of (CuxRh1–x)3(BTC)2 show the Cu–Rh stretching mode, indicating that mixed-metal Cu–Rh nodes are formed after transmetalation.

Density functional theory studies confirmed the assignment of a Raman peak at 285 cm–1 to the Cu–Rh stretching vibration. Electron paramagnetic resonance spectroscopy experiments further supported the conclusion that Rh2+ ions are substituted into the paddlewheel nodes of Cu3(BTC)2 to form an isostructural heterometallic MOF, and electron microscopy studies showed that Rh and Cu are homogeneously distributed in (CuxRh1–x)3(BTC)2 on the nanoscale.

Brantley & Long’s Collaborative Research

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The Brantley Lab and the Long Group published collaborative research “Vinyl-addition polymerizations of cycloallenes: synthetic access to congeners of cyclic-olefin polymers” in Polymer Chemistry. Co-first authors include Nick Galan with the Brantley Lab and Justin Burroughs with the Long Group. 

Their research demonstrates that vinyl-addition polymerization of cycloallenes is a potentially valuable strategy for preparing tunable analogues of cycloolefin polymers. Cycloallenes can be polymerized in a well-controlled manner at room temperature using a simple Ni catalyst. 

“This route does not require high strain monomers to achieve cyclic motif incorporation, and copolymerization with acyclic monomers is possible, but not required to achieve good conversion,” Galan said. “Taken together, these results suggest that vinyl-addition polymerizations of cyclic allenes could provide a reliable synthetic route toward heretofore inaccessible materials.”

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Do Lab Published in Analytical Chemistry

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The Do Lab published their research “Cytotoxicity of α-Helical, Staphylococcus aureus PSMα3 Investigated by Post-Ion-Mobility Dissociation Mass Spectrometry” in Analytical Chemistry.

Staphylococcus aureus, a major bacterial human pathogen, secretes phenol-soluble modulin (PSM) peptides to stimulate inflammatory responses and kill human cells. PSMα3 is the prominent member of the PSM family and exerts its toxic function via the formation of cross-α fibrils. The fibril structure of PSMα3 resembles the eukaryotic amyloid fibrils found in the brain of Alzheimer’s disease patient, but each unit is an α-helix peptide and not a β-strand.

In this study, the Do Lab investigated how oligomeric structures and interactions with cell membrane mimetics could determine peptide cytotoxicity. To overcome the dynamic nature of interaction and aggregation process, they use ion mobility spectrometry mass spectrometry (IMS-MS) to measure the molecular shapes of the oligomeric species.

Due to the weakly-bound nature of these oligomers, it is possible for them to dissociate within the mass spectrometer. This phenomenon, called post-ion mobility dissociation, has been well documented in the past but has not been considered in previous biomolecular self-assembly studies.

The Do Lab took advantage of this typically undesired phenomenon to elucidate the molecular structures of the oligomers and determine the number of detergent molecules (which mimic the lipids in cell membrane) required to stabilize the complexes.

Consequently, the most toxic PSMα3 variant was shown to preserve its α-helical signature and required the smallest number of detergent molecules, indicating that a key virulence factor of toxic PSMα3 lies in its ability to quickly insert into the cell membrane. The same approach can be applied to similar peptide systems. Amber Gray, first author and graduate student said, “Ultimately, our study highlights the ambiguity previously present in IMS-MS data and sheds new insight into the interpretation of such data in biomolecular self-assembly studies.”

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Musfeldt Group’s Recent Achievements

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The Musfeldt Group’s research area focuses on experimental materials chemistry and physics. They employ a variety of spectroscopic methods to reveal and control the properties of quantum materials. External stimuli are used to tune these properties in order to explore new physical phenomena and uncover properties of technological relevance.

The Musfeldt Group provides a very unique opportunity for students with the DMREF team (Designing Materials to Revolutionize and Engineer our Future). This year, the team received “The Creativity Extension which is the highest honor in DMR,” Musfeldt said. “The team received an extra $450,000 for it this year.”

The group has also been busy publishing papers such as “Piezochromism in the magnetic chalcogenide MnPS3” in npj Quantum Materials. Nathan Harms, graduate student in the Musfeldt Group, is the lead author. This research explores combining high-pressure optical spectroscopies and first-principles calculations to reveal piezochromism in MnPS3. Photographs are of piezochromic MnPS3 inside the diamond anvil cell at several characteristic pressures and also after release at room temperature. These images show a gasket hole diameter of 325 μm. The diamond culets are 500 μm.

Musfeldt was also published a cover article in Physics Today titled “Nanotubes from layered transition metal dichalcogenides.”