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
Prof. Zach Heiden
Dept. of Chemistry
Washington State University
 
May 11th @ 3:15 in SL 130
Prof. Larry Dalton
Dept. of Chemistry
University of Washington
 
May 17th @ 3:15 in SL 130
Thesis Defense
Kyle Burns
Graduate Student
Dept. of Chemistry
Western Washington University
 
May 18th @ TBD in AW 204
Scholar's Week Keynote Speaker
TBD
 
May 23rd @ 3:15 in SL 140
Thesis Defense
Sierra Reed
Graduate Student
Dept. of Chemistry
Western Washington University
 
May 24th @ 3:15 in SL 130
Thesis Defense
Ian Smith
Graduate Student
Dept. of Chemistry
Western Washington University
 
May 25th @ 3:15 in SL 130
Patrick Shelton
UW Travel Award Recepient
Chatterjee Research Lab
University of Washington
 
June 1st @ 3:15 in SL 130
Prof. David Tyler
Department Head
Dept. of Chemistry and Biochemistry
University of Oregon

 

 
 

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