Events

Seminar Schedule

Seminars are usually held on Friday afternoon in room SL SL 130 at 3:15 pm, unless otherwise noted.  Graduate student seminars are on Fridays in SL 130 or SL 110 at 3:15 pm, unless otherwise noted.  Seminar speakers are available from 2:30 pm until 3:00 pm in CB275 for discussion.  Refreshments are provided 15 minutes prior to the seminar in CB275.

The department strives to offer a diverse and vibrant seminar program. Each year leading researchers from outside the department, as well as faculty and graduate students from Western, present and discuss their cutting-edge research. This is an excellent opportunity for students, faculty, staff, and visitors to actively participate in the scientific community. In addition, many outside seminar speakers are recruiting graduate students for their respective programs and are eager to discuss their program. All are welcome and encouraged to attend!  

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Winter Quarter 2019

January 11th @ 3:15 in SL 130
"Undergraduate research opportunities in WWU Chemistry"
Prof. Elizabeth Raymond
Chemistry Dept.
Western Washington University
 
January 18th @ 3:15 in SL 130
"On the Dark Side: Forbidden transitions in light-harvesting materials"
Prof. Cody Schlenker
Dept. of Chemistry
University of Washington
Abstract:
From charge trapping in semiconductors to exciton fission/annihilation to photocatalytic water splitting, optically dark states and non-covalent interactions can dramatically influence the behavior of light-harvesting materials. One specific example that I will discuss from our laboratory involves photon-initiated homolytic cleavage of hydrogen/oxygen bonds of water in an inter-molecular heptazine:H2O complex.
Heptazine-based materials, including graphitic carbon nitride and poly(heptazine imides), are garnering increasing attention due, in part, to their improving photocatalytic hydrogen evolution activities (approaching 0.04 mol h-1 g-1, with apparent quantum yields of 60%). As such, there has been a recent focus on understanding the photochemistry of these materials. One major roadblock that has impeded those mechanistic studies is the chemically-ambiguous nature of the bulk carbon nitride active material. We have combined time-resolved photoluminescence (TR-PL) spectroscopy and computational chemistry to reveal upper excited-state dynamics that engender inter-molecular proton-coupled electron transfer (PCET) from water to a structurally-distinct small-molecule heptazine photocatalyst. To the best of our knowledge, this is the first direct spectroscopic evidence that the heptazine unit drives H-atom abstraction from water by PCET. This result yields rare spectroscopic evidence of an upper-excited state reaction pathway in a heptazine:H2O complex. This photoreaction exhibits a significant kinetic isotope effect (KIE) of 2.9, indicating homolytic O-H bond scission of water, and it liberates detectable hydroxyl radicals. Our results lay the groundwork for molecular design rules aimed at controlling organic photochemical reactivity by manipulating early-time photophysical dynamics. Photophysical and photochemical insight from our results can be leveraged in solar fuels research, photovoltaics, and LEDs.
 
January 25th @ 3:15 in SL 130
"DNA Circuits for Diagnostics: Evolved and Designed DNA"
Prof. Peter Allen
Dept. of Chemistry
University of Idaho
Abstract:
Designed DNA, DNA aptamers and DNA for diagnostics. DNA circuits are designed DNA-DNA reactions that can perform computations and amplify signals. Aptamers are single-stranded DNA oligonucleotides that are evolved to bind to specific molecules including protein biomarkers. We show progress to the integration of evolved and designed DNA for diagnostics. Microparticle substrates for DNA-DNA reactions have allowed for easy read-out of the fluorescent output of these reactions. This talk will introduce DNA circuits, non-enzymatic amplification, and the use of colloidal particles as a platform for biochemical assays.
 
February 1st @ 3:15 in SL 130
"Quantum Chemistry Beyond Quantum Chemical Calculations"
Prof. Cristopher Camacho
Dept. of Chemistry
University of Costa Rica
Abstract:
When chemists think of the term "quantum chemistry", we usually think of electronic structure calculations, especially DFT calculations in a program package like Gaussian. This talk will explore some aspects of quantum chemistry beyond electronic structure theory, relying on group theory and graph theory to develop a deeper understanding of chemical space. I will spend the first half of this talk on a graph theory approach to enumerate molecules. In the second half of the talk I will discuss our recent implementation of the DFTB+ electronic structure package on graphical processing units (GPU).
 
February 8th @ 3:15 in SL 130
"Immobilized enzyme microreactor development and optimization"
Prof. Golfam Ghafourifar​
Dept. of Chemistry
University of the Fraser Valley
Abstract:
The human body is made of billions of living cells, each containing a vast number of biomolecules. Biochemical studies, including protein studies, have provided much information about diseases and biochemical markers like proteins are used as indicators for diagnosis. To study proteins’ functions, it is important to understand their structure, composition and interactions. The field called proteomic includes studies of protein separation, identification, quantification and sequence analysis, and provides a means for understanding and mapping protein function in cells.
 
Enzymatic digestion of proteins, a common technique used in bottom-up proteomics, can be achieved with immobilized or insoluble enzymes. Advantages of using immobilized versus soluble enzymes include: reusability, integration with fluidic systems, and use of high enzyme-to-substrate ratios to accelerate protein digestion while simultaneously suppressing autolysis peaks that interfere with chromatographic and MS-based analyses. A simple procedure is insolubilization by cross-linking agent, which is a method we have been investigating for making immobilized enzyme particles. The reaction takes place at room temperature under mild conditions to produce particles that are soft and irregularly shaped agglomerates. We have been studying immobilized enzymes such as chymotrypsin as well as Lys-c formed by direct crosslinking. The efficiency of immobilization can be followed by UV-Vis spectrophotometry, HPLC, and capillary electrophoresis (CE). We have shown that when using GA-CT, the immobilization efficiency was found to be 96% of the total amount of chymotrypsin added. In addition, we attached chymotrypsin to internal wall of the capillary. Digestion was achieved by passing the protein through the immobilized enzyme reactor (IMER) and the digests were studied by capillary electrophoresis. CE-MS was used in order to separate and identify the peptides. The efficiency of protein digestion can be followed by CE, and HPLC. There are differences in digestion efficiency for different protein substrates, as expected, so we have undertaken a study to see how the substrate denaturation conditions affects the peptide maps for large proteins like bovine serum albumin (66 kDa) compared to smaller proteins like casein (23 kDa). The long term goal is to develop simple enzyme immobilization strategies that can be incorporated into various proteomics platforms.
 
February 15th @ 3:15 in SL 130
"Synthesis and Biological Activity of Furanosesquiterpenoids Related to Wortmannin"
Prof. Brian Goess
Chemistry Department
Furman University
Abstract:
The phosphatidylinositol-3-kinase (PI3K) pathway regulates cellular metabolism and is upregulated in many cancers, making it an attractive chemotherapeutic target. Wortmannin is a well-known and potent inhibitor of PI3K; however, its potential as a chemotherapeutic is limited due to its instability, lack of selectivity, and lengthy chemical synthesis. In contrast, hibiscone C is a structurally simpler and less studied member of the furanosteroid family. We completed a total synthesis of hibiscone C and demonstrated that it competitively inhibits PI3K activity in intact cells, slows proliferation, and induces cell death.  Hibiscone C and other members of the furanosteroid family may therefore serve as a productive scaffold for the development of therapeutically relevant PI3K inhibitors. 

In pursuit of an even more biologically active furanosteroid, we have also synthesized hibiscone B and its acetylated analog.  Our syntheses, the first reported for both natural products, solve an important challenge to the synthesis of related members of the furanosesquiterpenoid family, namely the regio-, chemo-, and stereoselective reduction of one of two carbonyls in the diacylfuran subunit.  These findings will be presented and their value discussed, particularly as it related to ongoing chemical biology efforts in our lab.

February 22nd @ 3:15 in SL 130
Prof. Robert Szilagyi
Department of Chemistry and Biochemistry
Montana State University
 
February 26th @ 3:30 in SL 110
"The Evolving Periodic Table and its Incredible Elements!"
ACS Webinar
Sponsored by the Western Chemistry Club
 
March 1st @ 3:15 in SL 130
TBD
 
March 8th @ 3:15 in SL 130
Prof. Lee-Ping Wang
Department of Chemistry
University of California Davis
 
March 15th @ 3:15 in SL130​
Prof. Katharine White
Dept. of Chemistry and Biochemistry
University of Notre Dame
 

Click here to access the Seminar Archive.

Click here to access WWU Chemistry Research Publication Collections (including graduate thesis collection).