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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Spring Quarter 2018

April 3rd  @ 4:00 in SL 130
"Toward Pervasive Nonlinear Optics"
Prof. Garth Simpson
Dept. of Chemistry
Purdue University
Abstract:
The increasing availability of ultrafast laser sources provides ever broadening access to nontraditional light/matter interactions scaling nonlinearly with incident intensity, applications of which are described for addressing crystal analyses in structural biology and pharmaceutical sciences. In structural biology, determination of high-resolution structures of proteins serve as the foundation upon which rational drug design is built. Following discovery of new drug candidates, controlling or preventing crystallization is an essential step to ensure bioavailability and efficacy. In both applications, the unique symmetry relationships arising in nonlinear optical interactions provide exquisite selectivity for detection and quantification of chiral crystals. Topics to be covered in the presentation will include opportunities and challenges in designing nonlinear optical instrumentation capable of supporting routine, benchtop measurements in applications spanning structural biology, pharmaceutical sciences, and in vivo analyses. 
 
April 6th @ 3:15 in SL 130
“The Influence of Thiolate Ligands on Iron Dioxygen Chemistry”
Prof. Julie Kovacs
Dept. of Chemistry
University of Washington
Abstract:
Dioxygen activation by non-heme Fe-enzymes, such as cysteine dioxygenase (CDO),1-2 isopenicillin N-Synthase (IPNS),3 and ergothioneine (EgtB), 4 has been proposed to proceed through several intermediates, including Fe-superoxo(O2 – ), -hydroperoxo( - OOH), and/or high-valent oxo species. Thiolate (RS– ) ligands have been shown to lower the activation barrier to O2 binding, and facilitate peroxo OO bond cleavage, and HAT reactions. Although they proceed via similar intermediates, CDO catalyzes S-O bond formation, whereas IPNS and EgtB catalyze C-S bond formation. There are few reported examples of wellcharacterized RS-Fe-(O2, OOH) intermediates. This talk will show that reduced bis-thiolate ligated [FeII(S2 Me2N3(Pr,Pr)] reacts with O2 at low temperatures (≤ –70 ˚C) to afford two metastable intermediates, en route to a singly oxygenated sulfenate (RSO– ) complex. The first of these intermediates is also obtained when KO2 is added to the oxidized derivative, [FeIII(S2 Me2N3(Pr,Pr)]+ . Oxo atom donors, ArIO, react with the latter to afford a metastable intermediate with properties dependent on the ArIO, which convert to an identical FeIII-S(R)O– product. 5 The crystal structure of an oxo atom donor adduct, PyN-O-FeIII (Figure 1), containing stronger X-O bonds will also be described. Aryl iodides (ArI) inhibit this reaction providing kinetic evidence for the involvement of an Fe(V)-oxo. HAT reactivity, TD-DFT calculations, and spectroscopic characterization of the intermediates formed in the O2 and KO2 reactions support the formation of a reactive Fe-O2 – . Thiolates are shown to facilitate the activation of strong (92 kcal/mol) C-H bonds.
1. D. Kumar, W. Thiel, S. P. de Visser, J Am Chem Soc., 2011,133,3869.
2. E. J Blaesi, B. G. Fox, T. C. Brunold, Biochemistry 2014, 53, 5759.
3. E. Y. Tamanaha, B. Zhang, Y. Guo, W.-C. Chang, J. M. Bollinger, C. Krebs, J. Am. Chem. Soc. 2016,138, 8862.
4. Wei W.-J., Siegbahn P. E. M., Liao R.-Z. "Theoretical Study of the Mechanism of the Nonheme Iron Enzyme EgtB". Inorg. Chem. 2017, 56, 3589.
5. Villar-Acevedo, G.; Lugo-Mas, P.; Blakely, M. N.; Rees, J. A.; Ganas, A. S.; Hanada, E. M.; Kaminsky, W.; Kovacs, J. A., J. Am. Chem. Soc. 2017,139,119.
 
April 13th @ 3:15 in SL 130
College to Career Discussion Panel
Chemistry Dept.
Western Washington University
 
April 20th @ 3:15 in SL 130
"Electronic Structure and Reactivity of Oxidized Metal Phenoxides"
Prof. Tim Storr
Dept. of Chemistry
Simon Fraser University
Abstract:
The interplay of redox-active transition metal ions and pro-radical ligands in metalloenzyme sites has generated considerable interest. The Cu(II)-phenoxyl radical form of galactose oxidase, as well as the Fe(IV)=O porphyrin radical intermediate of P450 enzymes are principal examples. Both of these enzymatic systems have inspired efforts to develop small molecule mimics capable of mild and selective oxidation chemistry. Recent developments show that ligands serving as electron reservoirs offer opportunities to expand catalysis, especially by conferring to first-row transition metals a “noble metal-like” reactivity.[1] We have extensively investigated the chemistry of a series of oxidized mono- and bis-phenoxide metal complexes, which demonstrate that small variations of the ligand structure affect the oxidation locus. Characterization of oxidized species by both experimental and theoretical methods has afforded significant information about the electronic structure of these ligand radical systems. Building on this work, recent studies with a series of oxidized nitridomanganese(V) salen complexes demonstrate that nitride activation is dictated by remote ligand electronics.[2] We are currently investigating the reaction mechanism and further applications of this chemistry.
1. P. J. Chirik and K. Wieghardt, Science, 2010, 327, 794.
2. R. M. Clarke and T. Storr, J. Am. Chem. Soc. 2016, 138, 15299
 
April 27th @ 3:15 in SL 130
"Using Free Energies for H+ and H– Transfers to Design Catalysts for the Reduction of CO2"
Dr. Aaron Appel
Scientist and Associate Division Director
Catalysis Science Group
Pacific Northwest National Laboratory
Abstract:
The wide spread and efficient use of carbon-neutral energy will require the storage of electrical energy in the form of high energy density fuels. The utilization of inexpensive substrates such as CO2 provides an opportunity for large-scale energy storage, and in particular, CO2 can potentially be converted to liquid fuels for use in transportation. To efficiently interconvert energy and fuels, catalysts are required for these multistep transformations. In enzymes, catalytic intermediates are closely matched in energy, which provides inspiration for the design of catalysts that can avoid large mismatches in energy throughout the catalytic cycle. While this general approach has been extensively used for designing catalysts for hydrogen production and oxidation, it is equally valuable for the production and utilization of fuels based on carbon. By applying these principles, we have designed molecular catalysts based on first-row transition metal complexes for the hydrogenation of CO2 to formate.
 
May 4th @ 3:15 in SL 130
"Incorporation of Fluorescent Dye Molecules into Molecular Scaffolds: From Molecular Sensors to Switchable Catalysts”
Prof. Zach Heiden
Dept. of Chemistry
Washington State University
Abstract: 
Increased environmental and impurity restrictions on consumer products, also the desire to reduce the cost and energy requirements of chemical transformations, have established a critical need for the development of more selective and efficient catalysts. An attractive approach to addressing this need is the use of catalysts that can be altered through post-synthetic modifications. Several commonly employed methods to change catalyst reactivity post-synthesis include the manipulation of pH, photoactivation, or even changes in solvent. This talk will discuss the synthesis, characterization, and reactivity of fluorescent dye-containing main group compounds that are capable of exhibiting a colorimetric response upon binding substrate molecules. This talk will also describe the incorporation of fluorescent dye-containing ligands into metal and main group complexes for switchable reactivity.  A brief discussion of the graduate program in chemistry at Washington State University will also be provided.
 
May 11th @ 3:15 in SL 130
"Theory-Guided Road Map for Electro-Optics and the Information Technology" 
Prof. Larry Dalton
Dept. of Chemistry & Chemical Engineering
University of Washington
Abstract:
Chipscale integration of electronics and photonics is well recognized as a critical next step in the evolution of information technology (telecommunications, computing, sensing, metrology, imagining, and robotics).  Electro-optics is central to such integration.  We use multi-scale theoretical methods (quantum & statistical mechanics and beyond) to develop a road map for development of organic electro-optic materials and their integration into silicon photonic, plasmonic, photonic crystal, and metamaterial devices.  This paradigm has already produced a factor of nearly 1000 improvement in electro-optic device performance yielding devices with drive voltage-length performance of 40 V-micrometers, single channel bandwidths of greater than 1 THz, energy efficiency for digital information processing of 1 femtojoule/bit, device footprints of 1 micrometer squared, and insertion loss of less than 2 dB.  Such devices now permit gain to be realized in telecommunication systems and wireless signals to be converted directly to fiber optic transmission without the use of electronics.  Extraordinary signal linearity has also been achieved.  Theory has not only permitted the design of dramatically improved organic electro-optic materials but has also permitted simulation of the performance of materials in devices, elucidating the importance of interfacial interactions.  Multi-scale theoretical simulations suggest that another factor of 500 improvement may be possible, permitting not only a revolution in electro-optic technology but also in photodetector technology through exploitation of optical rectification.
 
May 17th @ 3:15 in SL 130
"Secondary Sphere Influences on Kinetic Enhancement of Nitrite Reduction"
Thesis Defense
Kyle Burns
Graduate Student
Dept. of Chemistry
Western Washington University
 
May 18th @ 4:00 in AW 204
"Discovering genes essential for immune function"
Bruce Beutler, M.D.
Regental Professor and Director of the Center for Genetics of Host Defense
University of Texas Southwestern Medical Center at Dallas
2011 Nobel Prize winner in Physiology or Medicine
Abstract:
As chemists may screen to find drugs that alter biological activities, geneticists may screen for mutations that alter biological activities.  By damaging genes at random with a chemical mutagen and then tracking down the mutations that cause phenotype, it is possible to find every essential part of a biological “machine.”  Random germline mutagenesis in mammals has produced impressive discoveries but historically was a slow process.  Often years were required to find the mutational causes of interesting phenotypes.  Recently we have developed a means of finding causative mutations instantaneously.  When a phenotype is detected, its cause is known.  Over the last four years we have severely damaged or destroyed approximately 36% of all protein-encoding genes in the mouse.  About 600 genes have been ascribed function in either innate or adaptive immunity.  Approximately half of these genes were not previously known to be important in immunity.  Some of the new genes, and their importance in immunity, will be discussed.
 
May 23rd @ 3:15 in SL 140
"Driving Sortase-Mediated Ligations Using Metal-Coordinating Peptides"
Thesis Defense
Sierra Reed
Graduate Student
Dept. of Chemistry
Western Washington University
 
May 24th @ 3:15 in SL 130
"Structure Determination of a Bioengineered Human/Porcine Factor VIII for Hemophilia A Treatment, and Improvements to the Human Factor VIII Model"
Thesis Defense
Ian Smith
Graduate Student
Dept. of Chemistry
Western Washington University
Abstract:
Blood coagulation factor VIII (FVIII) is a non-enzymatic protein cofactor which plays a crucial role in the formation of a stable blood clot. Absence or deficiency of FVIII results in the blood disorder hemophilia A; with symptoms including internal hemorrhaging and the inability to stop bleeding from open wounds. Treatment of hemophilia A relies on replacement of FVIII with blood, plasma, or protein concentrate infusions. Unfortunately, approximately 30% of patients receiving replacement FVIII generate pathologic anti-FVIII inhibitory antibodies, which both reduce the effectiveness of the FVIII therapeutic and increase the severity of hemophilia A symptoms. We report the determination of the molecular structure for “Et3i”, a next-generation human/porcine chimeric FVIII protein for hemophilia A therapy. At 3.2 Å resolution with a Rwork of 0.2146 and Rfree of 0.2879, this will be the highest resolution structure of FVIII to date and will be of substantial interest to the hematological community. Furthermore, an improved model of human FVIII with more robust geometry and amino acid register assignment, and a Rwork of 0.2655, and Rfree of 0.2895 based on previous 3.7 Å data has been constructed. Lastly, progress has been made towards the structural determination of the inhibitory antibodies M6143, 2A9, and B136 in complex with the C1 domain of human FVIII. Details of these interactions could inform the development of future hemophilia A protein therapeutics with reduced immunogenicity.
 
May 25th @ 3:15 in SL 130
"Tools for Studying the Biochemical and Biophysical Consequences of Histone PTMs"
Patrick Shelton
UW Travel Award Recipient
PhD Graduate Student
Chatterjee Research Lab
University of Washington
Abstract:
"Histone post-translational modifications (PTMs) are important epigenetic markers that regulate diverse cellular processes. The enzymes that place and remove PTMs on histone N-terminal tails (‘writers’ and ‘erasers’) are essential to homeostasis and consequentially their dysregulation can lead to various disease states, including cancer. Chemical biology is aptly suited to study the interplay between histone PTMs and writers or erasers. Our lab employs chemical tools to study simple biological systems in order to assess how PTMs such as methylation, acetylation and modification by the small ubiquitin-like modifier (SUMO) protein interact with important chromatin modifying enzymes individually, and as parts of larger transcription repressing complexes. My research in the Chatterjee lab has focused on development of a novel C-terminal peptide thioesterification methodology for synthesizing full-length proteins, as well as assessing the effect of additional proteins and histone PTMs on the activity of eraser proteins lysine specific demethylase 1 (LSD1) and histone deacetylase 1 (HDAC1)."
 
May 30th @ 3:15 in SL 140
"Development of Regio- and Diastereoselective Samarium (II) Iodide Mediated Allylic Benzoate Reductions"
Thesis Defense
Trevor Stockdale
Graduate Student
Dept. of Chemistry
Western Washington University
 
June 1st @ 3:15 in SL 130
"Homing Pigeons, Degradable Plastics, and Solvent Effects; How Caged Radical Pairs Impact Everyday Chemistry"
Prof. David Tyler
Department Head
Dept. of Chemistry and Biochemistry
University of Oregon
Abstract:
How do homing pigeons navigate?  How do we design plastics so they degrade after they are used?  Why are solar energy conversion systems with donor and acceptor complexes so inefficient?  Why do bonds break more readily if they are under mechanical stress?  It turns out that radical cage effects are important in understanding the answers to these and numerous other practical questions involving chemical reactivity.  In this seminar, I will introduce the concept of caged radical pairs, and then I will show why caged radical pairs are key intermediates in the systems mentioned above and in radical reactions, in general. 

 

 
 

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