Department of Chemistry and Biochemistry Seminars
Friday, Jan 11
Prof. Jeremy Johnson from the Dept. of Chemistry and BIochemistry at Brigham Young University, will present "Distinguishing Nonlinear Terahertz Excitation Pathways with 2-Dimensional Spectroscopy." Byker Auditorium 3:10 pm. Prof. Erik Grumstrup host.
Abstract: High-field terahertz (THz) spectroscopy is enabling the ultrafast study and control of matter in new and exciting ways. However, when intense electromagnetic pulses are used in any kind of pump-probe spectroscopy, several nonlinear excitation pathways can result, leading to scenarios that required the development of multi-dimensional spectroscopies to illuminate the observed dynamics. I’ll describe a clear example where 2-dimensional (2D) THz vibrational spectroscopy is needed to distinguish between nonlinear-excitation pathways in crystalline CdWO4.
Friday, Jan 18
Dr. David Zigler Assistant Professor from the Dept. of Chemistry and Biochemistry California Polytechnic State University-San Luis Obispo. will present "Electronic State Tuning through Metal-Ligand Covalency: First Row Transition Metals are Worth Exciting!"
Byker Auditorium at 3:10 pm. Professor Erik Grumstrup is the host.
Abstract: First row transition metal (TM) complexes are attractive as photosensitizers. Often as highly-colored as complexes formed from 2nd or 3rd row TMs, metals from the first row are orders of magnitude more abundant. The challenge in using 1st row TM complexes is that they have low-lying metal-centered ligand field states (MC) that provide a pathway for rapid relaxation to the ground state. Recent results show that complexes with highly covalent metal-ligand bonds have destabilized MC states and long-lived charge transfer excited states (CT). Our group studies ligand substituent effects on metal complexes formed with dithiocarboxylic acid derivatives using a mixture of experimental and computational methods. This talk will discuss ligand design strategies and show a set of tris(dithiocarboxylate)cobalt(III) complexes with destabilized MC states and an unusual low-lying metal-to-ligand charge transfer (MLCT) state.
Thursday, Jan 24
Dr. Keith Hollis from the Dept. of Chemistry at Mississippi State University will present "Designing, Developing and Applying Molecules to Solve Tomorrow’s Problems: CCC-NHC Pincer Complexes: Early and Late Transition Metal Complexes – Synthesis & Applications." Byker Auditorium at 3:10 pm
Abstract: The Hollis Group designs and develops next-generation organometallic ligands and complexes (CCC-NHC pincers) for many applications, which often requires the development of new synthetic methodologies. Access to new molecules and materials is required to solve many of the technological challenges facing society, such as improving energy-efficiency, direct conversion of solar energy to useful forms, and more cost-effective access to medicines. These goals are reached by developing efficient, scalable syntheses of molecules with interesting properties.
Friday, Jan 25 -
Dr. David Y. Lee, Department of Chemistry and Materials Science & Engineering Program, Washington State University will present "Imaging Gas-Surface and Solution-Surface Reactions in Small Steps."
Abstract: Using a scanning tunneling microscope in an ultra-high-vacuum environment, our group studies materials and molecular surfaces interacting with structurally simple but highly reactive oxygen and hydrogen atoms. In particular with an extremely low dosage, O-atoms can open the band gap of graphene to a few hundred meV with a contribution 0.15±0.05 holes per atom. On the other hand, sequential interactions with O- and H-atoms can lead to nm-scale erosion on graphite step edges. For organo-metallic monolayers, these highly reactive O-atoms prefer to bind at counterintuitive surface sites with inert and saturated alkyl groups over with fully exposed single metal atoms. We are also interested in using sequential solution treatments to fabricate novel surface structures with a full-sample coverage. Imaged in an ambient condition, we show that stable insertion of single-atom metal centers into an organic monolayer can be achieved via careful control of solvent, reaction time and temperature.
Byker Auditorium at 3:10 pm. Prof. Tim Minton host.
Friday, Feb 1-
Dr. Anja Kunze Asst. Professor, Dept. of Electrical and Computer Engineering (MSU) will present "Nano-Scaled Forces for Neurotherapeutics."
Abstract: In recent years, magnetic nanoparticles have paved the way in cell biology to precisely separate biological units from suspension, to deliver therapeutic agents to single cells, or to guide the growth of biological tissues. The underlying principle of these applications is a mechanical force, which is generated at the magnetic particle through an external magnetic field gradient. Force amplitude and direction are dependent on the topography of the magnetic field gradient, the magnetic properties, the dimension and application-specific surface properties of the superparamagnetic nanoparticle. Operating these forces based on superparamagnetic nanoparticles inside brain cells, which we call nano-scaled forces, have the tremendous potential to transform neurotherapeutics. Designing brain cell appropriate force ranges without interfering with degenerative processes remains, however, a technical challenge. In this seminar, I will talk about our mechano-stimulating platform which combines micropatterns of magnetic gradients with neurons derived from the cerebral rat cortex to probe nano-scaled forces at neuronal cell function. I will show our recent progress in designing force ranges in the lower piconewton range and how these forces impact proteins, calcium signals and the transport of organelles. Specifically, I will address the question of how we can target nano-scaled forces to the intracellular versus the extracellular space and how we can use mechanical stimulation to our advantage in next-generation neurotherapeutic devices.
Bio: Anja Kunze is an assistant professor in the Department of Electrical and Computer Engineering at Montana State University (MSU). She was a postdoctoral researcher and assistant adjunct professor at the University of California, Los Angeles (UCLA) before joining MSU in 2016. In 2012, she obtained her Ph.D. in Microsystems and Microelectronics from the École Polytechnique Fédérale de Lausanne (EPFL, Switzerland) and her M.Sc. in Electrical Engineering from the Technische Universität Dresden (TUD, Germany) in 2007. Dr. Kunze’s postdoctoral work was recognized by two fellowships from the Swiss National Science Foundation and the UC Systemwide Bioengineering Award in 2013. Her neuroengineering research lab focuses on advancing brain-on-a-chip technology using micro- and nanosystems, tissue engineering, calcium assays, and micro-scaled electrophysiology to regulate neuronal cell growth and function.
Byker Auditorium at 3:10 pm
Friday, Feb 8
Prof. Scott Warren from UNC, Chapel Hill will present "2D Heterostructures for Energy Storage and Electronics: Exploring the Limits of Weak and Strong Interlayer Interactions."
Abstract: The ability to alter distances between atoms is among the most important tools in materials design. Despite this importance, controlling the interlayer distance in stacks of 2D materials remains a challenge. This talk will present two strategies for controlling this distance, thereby giving rise to several fascinating new classes of materials for electronics and energy storage.
In the first strategy, we self-assemble a monolayer of organic molecules between monolayers of a 2D semiconductor such as MoS2 or phosphorene. The resulting 3D materials are crystalline and have an increased interlayer distance, which gives rise to fascinating and unusual electronic properties. We demonstrate a 3D hybrid made from monolayer MoS2 and organic molecules that retains the desirable properties of monolayer MoS2, such as strong photoluminescence. Even more surprising is that these materials are relatively conductive—thereby allowing the desirable properties of 2D materials to be harnessed in a 3D format that is suitable for electronic devices.
The second strategy introduces a new pathway to reduce interlayer distance. We utilize “2D electrenes,” a new 2D material with an electrical conductivity that rivals silver. 2D electrenes have radically different electronic structures: they have planes of electrons that are physically separated from planes of cations. Using DFT calculations and preliminary experiments, we show that electrenes act as electron donors to 2D metals, semiconductors, and insulators. These materials are the 2D analogs of donor-acceptor systems and have interlayer distances that approach those of covalent or ionic materials. I will describe these structures and their fascinating properties, as well as their role in battery electrodes.
Byker Auditorium at 3:10 pm. Prof. Nicholas Stadie host.
Friday, Feb 15
Dr. Bryan Eichhorn from the University of Maryland, Dept of Chemistry and Biochemistry, will present "Unravelling the Solid-Electrolyte-Interphase (SEI) Chemistry in Li-ion and Li-S Batteries." Byker Auditorium 3:10 pm. Prof. Rob Walker host.
The solid-electrolyte-interphase (SEI) that forms spontaneously between the electrode and electrolyte of virtually all organic-based batteries is critically important to battery function and stability but remains the least understood of all battery components. The role of stable SEIs for reversible operation of Li-ion batteries (LIBs) and the sulfur-based cathodes of Li-S batteries has been well-established, but their compositions and formation mechanisms are debated fiercely. The major organic SEI component of LIB anodes is believed by many to be lithium ethylene di-carbonate (LEDC), which is thought to have a high Li-ion conductivity but a low electronic conductivity thus protecting the Li/C electrode. Through comprehensive analysis of authentic and synthetic SEI components (single crystal and powder XRD, FTIR, elemental analysis, solid-state and liquid 1D and 2D NMR), we show that the previously synthesized “LEDC” chemical standards are actually lithium ethylene mono-carbonate (LEMC) which is most likely formed from a simple chemical pathway available in LIBs. Direct comparisons of authentic SEI grown on graphite anodes (1M LiPF6 in ethylene carbonate/dimethyl carbonate) suggest that LEMC, instead of LEDC, is likely the major SEI component. Single crystalline x-ray diffraction (XRD) studies on LEMC and LMC reveal unusual layered structures and Li+ coordination environments. LEMC has Li+ conductivities of above 10-6 S/cm similar to LiPON, while LEDC is almost an ionic insulator. The complex interconversions, equilibria and aggregation of LMC, LEMC and LEDC in dimethyl sulfoxide (DMSO) solutions are also briefly discussed. Surprisingly, the SEI layer in sulfur cathodes also consist of LEMC, which is formed by a completely different mechanism.
Friday, March 1
Dr. Mitch Smith (Michigan State). Prof. Joan Broderick host.
Friday, March 8
Dr. Alex Guo (Carnegie Mellon University). Prof. Jen DuBois host.
Friday, March 15
Dr. Orion Berryman (UM) Prof. Mary Cloninger host.
Tuesday, March 26
Ph.D Defense in Chemistry- Eric Smoll
Wednesday, March 27
Graduate Student Seminar - Max Koch
Friday, March 29
Dr. Elliot Hulley (University of Wyoming) Prof. Michael Mock host
Friday, April 5
PhD Defense in Chemistry - Jacob Remington
Friday, April 5
Prof. Timothy Warren (Georgetown University). Prof. Michael Mock host
Friday, April 12
Dr. John Tunge (Kansas). Prof. Matt Cook host
Friday, April 19- University Holiday
Monday, April 22
Graduate Student Seminar -Stella Impano
Friday, April 26
Graduate Student Seminar - Casey Kennedy
Friday, April 26
Dr. Joan Valentine (UCLA). Graduate students host.
Friday, May 3
Dr. Joe Topczewski (University of Minnesota). Prof. Matt Cook host.
Thursday, May 16
Graduate Student Seminar - Angela Patterson