Past Seminars & Events

Department of Chemistry celebrates inaugural Jeannette Brown Lectureship

Wednesday, February 3^rd, 2021

• 10:00 am - 11:30 am: Inaugural Jeannette Brown Lecture - Professor Richmond Sarpong (UC Berkeley)
  Introduction by David Blank, Mike Kress, Amjad Ali, Tao Wang. Dipannita Kalyani, Tom Hoye, and Jeannette Brown
  Professor Richmond Sarpong (UC Berkeley)
  "A Life Shaped by Diseases and Medicine in Sub-Saharan Africa"   ZOOM
• 11:30 am- 12:15 pm: Diversity, Equity, & Inclusion (DEI) discussion with Professor Richmond Sarpong for graduate students and postdoctoral scholars  ZOOM
• 12:45 pm - 1:15 pm: Diversity, Equity, & Inclusion (DEI) discussion with Professor Richmond Sarpong for staff and faculty  ZOOM
• 1:15 pm - 1:45 pm: science discussion with Professor Richmond Sarpong - open to all graduate students and postdoctoral scholars  ZOOM

Thursday, February 4^th, 2021

• 9:45 am - 11:00 am: Professor Richmond Sarpong (UC Berkeley) - keynote lecture
  "Break-it-to-Make-it Strategies for Chemical Synthesis Inspired by Complex Natural Products"  ZOOM
• 11:15 am - 12:12 pm: Dr. Olugbeminiyi Fadeyi (Merck Exploratory Science Center) - keynote lecture "Mapping Cell-Cell Interactions in Tumor Microenvironment via Photocatalytic Proximity Labeling" ZOOM
• 2:00 pm - 5:20 pm: Student flash talks
  • Session 1 - organic chemistry
    Host: Nick Race             Jeannette Brown Lecture Flash Talks Room 1  ZOOM
  • Session 2 - chemical biology and medicinal chemistry
    Host: Tom Hoye            Jeannette Brown Lecture Flash Talks Room 2  ZOOM
  • Session 3 - inorganic and organic chemistry
    Host: Valérie Pierre      Jeannette Brown Lecture Flash Talks Room 3  ZOOM
  • Session 4 - polymer, material, analytical/physical, and computational chemistry
    Host: Jessica Lamb       Jeannette Brown Lecture Flash Talks Room 4   ZOOM

Professor Richmond Sarpong is the invited speaker for the Department of Chemistry’s inaugural Jeannette Brown Lectureship, which is scheduled for Wednesday, Feb. 3, 2021. through Thursday, Feb. 4, 2021. Sarpong will present two virtual lectures and meet with students and faculty and the department’s Diversity & Inclusion Committee. This lectureship is sponsored by Merck and by donations to the Jeannette Brown Lectureship Fund.

Dr. Olugbeminiyi Fadeyi was originally from Nigeria. Currently working at Merck Exploratory Science Center as a Molecular Invention Scientist; he is developing a platform that integrates chemistry and biology to study novel mechanistic basis of human diseases to develop new therapeutics.

The Department of Chemistry established the Jeannette Brown Lectureship to honor the career and legacy of one of its outstanding alumna. This lectureship will bring experts in all fields of chemistry from around the world to the University of Minnesota, with emphasis on highlighting the work and careers of Black, Indigenous, and people of color in the chemical sciences. The lectureship reflects and celebrates the pioneering work of Jeannette Brown as a talented chemist in the pharmaceutical industry for 25 years, author, historian, and tireless leader and advocate for the inclusion and advancement of African American women in chemistry-related professional pursuits and careers.

Alumna Jeannette Brown

Brown is the first African American to receive a degree from the Department of Chemistry's graduate program, earning her master's degree in 1958. She is a former faculty associate in the Department of Pre-College Programs at the New Jersey Institute of Technology. For 25 years, she worked as a research chemist at Merck. She is the author of two books, "African American Women Chemists" and "African American Women Chemists in the Modern Era." She is a Société de Chimie Industrielle (American Section) Fellow of the Chemical Heritage Foundation (2004), and is a member of the first class of American Chemical Society (ACS) Fellows (2009). For her distinguished service to professionalism, she received the Henry Hill Award from the ACS Division of Professional Relations in 2020. For her work as a mentor to minority students and science education advocacy, she was elected to the Hunter College Hall of Fame in 1991; was honored by the University of Minnesota with an Outstanding Achievement Award in 2005; and received the ACS national award for Encouraging Disadvantaged Students into Careers in the Chemical Sciences in 2005.

The Jeannette Brown Lectureship is supported by donations. Supporters can go to the Department of Chemistry’s giving page to donate.

Professor Ashleigh Theberge
Department of Chemistry
University of Washington
Host: Professor Christy Haynes

Abstract

Studying cell signaling in complex environments using open microfluidics

Small molecule and protein signals provide a rich vocabulary for cellular communication. To better understand signaling processes in both normal and disease states, we have developed new open microfluidic platforms that accommodate the culture of multiple cell types in microfabricated compartments while allowing soluble factor signaling between cell types. Our microscale culture systems allow a 10- to 500-fold reduction in volume compared to conventional assays, enabling experiments with limited cells from patient samples. Furthermore, our devices are open, pipette accessible, interface with high resolution microscopy, and can be manufactured at scale by injection molding, increasing translation to collaborators in biological and clinical labs without chemistry and engineering expertise. This talk will also highlight our use of open microfluidic principles to develop novel strategies for hydrogel 3D printing, with applications in biology and materials science. Finally, I will share a system we have recently developed for at-home blood sampling and transcriptomics, with relevance to conducting human subjects research during the COVID-19 pandemic.

Professor Theberge

Ashleigh Theberge is assistant professor of chemistry and adjunct assistant professor of urology at the University of Washington. She holds a Bachelor of Arts degree from Williams College and a doctorate from the University of Cambridge. Her group develops microscale culture and analysis methods to study cell-cell, cell-extracellular matrix, and host-microbe interactions. She is also developing new methods for 3D printing and at home blood sampling/transcriptomics.

Selected awards include a National Institutes of Health (NIH) K Career Development Award (2014), Kavli Microbiome Ideas Challenge Award grant (2017), NIH Maximizing Investigators’ Research Award (MIRA) for Early Stage Investigators (2018), Beckman Young Investigator Award (2018), and Packard Fellowship for Science and Engineering (2019). She was elected co-chair for the Gordon Research Conference on Microfluidics in 2021.

Professor Joanna Atkin
Department of Chemistry
University of North Carolina at Chapel Hill
Host: Professor Renee Frontiera

Abstract

Near-field optical spectroscopy for the study of semiconducting nanostructures

Semiconducting nanostructures have been proposed as material platforms for a wide variety of photonic, electronic, and photovoltaic elements. In order to realize these applications, careful design and characterization of electronic properties such as dopant concentration, activation, and distribution are needed. I will discuss the use of near-field optical microscopy as a non-destructive method for chemical, structural, and electronic imaging in nanomaterials. Near-field optical techniques break the diffraction limit to access nanometer scale information through the lightning-rod properties of an illuminated atomic force microscope tip. Many nanoscale optical spectroscopies can be realized using this approach, but signal interpretation is often challenging due to convolutional effects between the tip and sample. I will discuss experimental and theoretical considerations in quantitative near-field optical microscopy in general, and then focus on two applications that illustrate the importance of understanding near-field interactions. In the first example, we use infrared near-field spectroscopy to resolve free-carriers in axially-doped silicon nanowires (SiNWs). We can detect local changes in the electrically-active doping concentration from the free-carrier absorption in both n-type and p-type doped SiNWs. The high spatial resolution (< 20 nm) allows us to directly measure dopant transition abruptness and charge carrier properties in the vicinity of interfaces in single and multi-junction SiNWs. In the second example, we use nano-Raman spectroscopy to study functionalized graphene, a derivative of graphene engineered to open a finite band gap. The high degree of chemical and physical disorder in these types of systems can be resolved with near-field spectroscopy, demonstrating its utility in understanding how local properties of nanomaterials affect functionality in optoelectronic and photovoltaic devices.

Research

Researchers in Professor Atkin's group develop and use techniques based on atomic-force microscopy (AFM) combined with optical spectroscopy to understand how nanoscale structure underpins functionality in molecular and inorganic semiconductors, solar cells, and biological systems. They take advantage of the “optical antenna” properties of the AFM tip to concentrate and locally enhance light, and use simulation tools to study how improve the light-matter interaction to increase spatial resolution, improve sensitivity, and explore new types of materials.

Professor Atkin

Professor Atkin obtained her Bachelor of Science degree from Victoria University of Wellington, in New Zealand. She completed her doctorate at Columbia University in New York, and went on to work as a postdoctoral researcher at the University of Washington and the University of Colorado, Boulder. She joined the University of North Carolina at Chapel Hill in 2015.

Gwendolyn "Gwen" A. Bailey, Ph.D.
Postdoctoral Scholar Research Associate in Chemistry
California Institute of Technology (Caltech)
Host: Ian Tonks

Abstract

Inside the Catalytic Cycle: Understanding Mechanism and Deactivation in Important C–C Bond-Forming Reactions

To meet the world’s growing demand for chemicals and fuels, design of more efficient and sustainable catalysts is needed. Central to all catalyst design efforts, however, is an underlying knowledge of how catalysts behave: how they bind, transform, and turnover substrates, and (just as importantly) how they decompose. For example, Ru-catalyzed olefin metathesis has emerged as an exceptionally powerful C–C bond forming technology for the synthesis of important pharmaceuticals, including the blockbuster hepatitis-C virus inhibitor Simeprevir. However, catalyst deactivation plagues widespread uptake in industry, with attendant issues of low product yield, challenging purification, and swollen costs. The first part of this seminar will illustrate how pinpointing deactivation processes in Ru-catalyzed olefin metathesis can lead to informed process and catalyst redesign. In the second part, the C–C coupling reactivity and electronic properties of some rare and unprecedented examples of terminal carbide complexes will be examined. While posited as key intermediates in important industrial processes including the Fischer Tropsch conversion of synthesis gas (CO and H₂) into long-chain hydrocarbons, terminal carbides have remained elusive in molecular form and hence have evaded detailed examination. Understanding the reactivity of these complexes can therefore inform on potential mechanisms in the industrial catalysts, as well as inspire de novo catalyst design. The first open-shell examples of these complexes will be presented, along with in-depth experimental and computational studies that shed light on electron delocalization and its consequences for reactivity.

Gwendolyn "Gwen" A. Bailey, Ph.D.

Gwendolyn "Gwen" A. Bailey, Ph.D.,  is a Natural Sciences and Engineering Research Council/Resnick Sustainability Institute Postdoctoral Fellow in synthetic inorganic chemistry at Caltech. She earned her doctorate from the University of Ottawa, and her Bachelor of Science from the University of British Columbia. Her research experience encompasses inorganic synthetic and catalytic methodologies; rigorous glovebox and schlenk techniques; and advanced inorganic characterization techniques, including multidimensional Nuclear Magnetic Resonance spectroscopy, single-crystal X-ray diffraction, Ultraviolet-visible Spectroscopy, Electron Paramagnetic Resonance spectroscopy, mass spectrometry, and infrared spectroscopy. At Caltech, Bailey's research focused on new ways to activate carbon dioxide (CO₂) using mixed-metal complexes. 

Ivan Moreno-Hernandez, Ph.D.
Postdoctoral Scholar
University of California, Berkeley
Host: Professor Lee Penn

Abstract

Advancing Sustainability through Electrocatalyst Discovery and Time-Resolved Nanoscale Structural Observations

Sustainable energy practices require electrochemical materials to couple renewable energy sources with our chemical and energy industries. This talk will focus on advancements in both the discovery of new electrochemical materials with improved performance and the development of new techniques to observe electrochemical reaction dynamics. We will first discuss the discovery of an earth-abundant class of electrocatalysts that are thermodynamically stable for the oxygen evolution and chlorine evolution reactions in acidic electrolytes. Our discussion will then focus on the development of electrochemical graphene liquid cell electron microscopy, a technique that allows electrochemical reactions to be observed at near-atomic resolution in real time.

Ivan Moreno-Hernandez, Ph.D.

Ivan Moreno-Hernandez, Ph.D., is a postdoctoral scholar at the University of California, Berkeley, He earned his Bachelor of Science degree from the University of Nebraska, Lincoln, and his doctorate from the California Institute of Technology. He hopes to use his knowledge of chemistry and physics to understand the fundamental principles that govern limiting factors in photoelectrochemical development, in order to optimize materials for solar-energy conversion.

Douglas A. Reed, Ph.D.
Postdoctoral Researcher
Columbia University
Host: Professor Nicholas Race

Abstract

Hybrid Organic-Inorganic Materials with Emergent Properties

Hybrid materials composed of both organic and inorganic components allow for precise synthesis of extended materials. In this talk, I will show how the tools of inorganic and organic chemistry can be leveraged to create highly specific electronic, structural, or guest responsive characteristics, producing materials with unprecedented functions.

The first part of my talk will focus on porous metal–organic frameworks (MOFs) for gas separation applications. These designer adsorbents could greatly reduce energy costs of current industrial separations and facilitate many emerging technologies. New frameworks are described that contain electron-donating metal sites, currently a rare feature in MOFs, which enable many new separations involving π-acidic gases through novel gas binding mechanisms. Furthermore, selective gas binding to specifically positioned, electronically interacting metal centers is demonstrated to induce framework structural changes that result in even greater energy efficiencies for separations than seen in rigid materials, moving beyond the thermodynamic limitations of classical adsorbents.

In the second part of the talk, I will discuss the use of atomically defined metal-chalcogenide clusters in single-molecule electronics applications. By precisely positioning surface organic ligands or tuning the composition of the cluster core, single-cluster junctions can be fabricated that display exciting properties like nonlinear current-voltage characteristics and directional charge transport. Due to the atomic precision of our materials, these features are highly reproducible across thousands of devices, substantially improving upon traditional nanocrystal-based junctions. The ability to accurately control junction features by modifying the electronic and structural properties of these clusters paves the way for utilization of these inorganic-based junctions in nanoscale electronics.

Douglas A. Reed, Ph.D.

Douglas A. Reed, Ph.D., is an academic research scientist designing new materials for applications in environmental solutions or nanotechnology. As a postdoctoral researcher at Columbia University, he is studying superatomic clusters and two-dimensional materials. He earned his Artium Baccalaureus in chemistry and physics from Harvard University where he worked on multinuclear metal clusters, and his doctorate from the University of California, Berkeley, studying metal-organic frameworks for gas separations.

Professor Amarda Shehu
Department of Computer Science
Volgenau School of Engineering

Abstract

AI-enabled Discovery of Macromolecular Structure, Dynamics, and Function

Biology has undergone many disruptions and revolutions that have opened or redirected entire domains of scientific enquiry. Anfinsen showed us that protein tertiary structure was largely encoded in the amino-acid sequence. John Kendrew’s famous sentences “The way in which the chain of amino acid units in a protein molecule is coiled and folded in space has been worked out for the first time. The protein is myoglobin, the molecule of which contains 2,600 atoms.” instigated decades of computational studies on macromolecular structure, dynamics, and function, starting with the seminal work of Scheraga, Karplus, Levitt, Warshel, and others. Some of the most interesting computational concepts and techniques were debuted in these studies, many of which we would now categorize as “artificial intelligence” (AI). In my own work, I focused heavily, and still do, on the question of knowledge representation, which is central to AI. Then came the data revolution and the revival of neural networks. What was old became new. My laboratory showed data-driven models to be more powerful in many respects, yet not always satisfying. And now comes news DeepMind’s Alphafold2 has solved a 50-year grand challenge in biology. Many of us wonder what these increasingly more frequent AI disruptions mean for our disciplines, our students, and our careers. I will conclude this talk with my admittedly biased perspective and argue that, while we still need to figure out a new collaborative medium, these AI disruptions provide wonderful opportunities to get into complex, messy, integrative scientific enquiries.

Professor Amarda Shehu

Dr. Amarda Shehu is a professor in the Department of Computer Science in the Volgenau School of Engineering with affiliated appointments in the Department of Bioengineering and School of Systems Biology at George Mason University. She is also co-director of the Center for Advancing Human-Machine Partnerships, a Transdisciplinary Center for Advanced Study at George Mason University. Shehu obtained her doctorate in computer science from Rice University in 2008, where she was also a National Institutes of Health pre-doctoral fellow. 

Shehu’s research focuses on novel algorithms in artificial intelligence and machine learning to bridge between computer and information sciences, engineering, and the life sciences. In particular, her laboratory has made many contributions in bioinformatics and computational biology regarding the relationship between macromolecular sequence, structure, dynamics, and function. 

Shehu has published more than 130 technical papers with postdoctoral, graduate, undergraduate, and high-school students. She is the recipient of a National Science Foundation (NSF) CAREER Award, and her research is regularly supported by various NSF programs as well as state and private research awards. Shehu is also the recipient of the 2018 Mason University Teaching Excellence Award, the 2014 Mason Emerging Researcher/Scholar/Creator Award, and the 2013 Mason OSCAR Undergraduate Mentor Excellence Award. She currently serves as program director at the NSF Foundation in the Information and Intelligent Systems Division of the Computer and Information Science and Engineering Directorate.

Stewart A. Mallory, Ph.D.
Arnold O. Beckman Postdoctoral Fellow in Chemical Sciences
California Institute of Technology (Caltech)
Host: Professor Ilja Siepmann

Abstract

Phase Behavior and Self-assembly of Active Colloids

In recent years, a new type of synthetic microparticle has captured the imagination of researchers across the physical and biological sciences. These so-called active colloids convert chemical or environmental free energy into irreversible directed motion. Impressively, the active force generated by the particles can lead to self-propelling speeds of tens of hundreds of microns per second. Active colloids challenge our theoretical understanding of nonequilibrium phenomena and simultaneously represent a potentially innovative approach to directed transport and material design at the microscale. In this talk, I will discuss one of the most striking features of active colloids, which is their rich and complex nonequilibrium phase behavior. Special emphasis will be given to motility-induced phase separation where purely repulsive active colloids undergo a liquid-gas phase transition. This talk will provide a quantitative understanding of this phenomenon by generalizing concepts in classical statistical mechanics and liquid state theory to active systems. This newfound understanding can be leveraged to improve the self-assembly of many complex colloidal structures using active colloids.

Stewart A. Mallory, Ph.D.

Stewart A. Mallory, Ph.D., is the Arnold O. Beckman Postdoctoral Fellow in Chemical Sciences at Caltech. Previously, he was the Alliance for Graduate Education & the Professoriate (AGEP) California Alliance Postdoctoral Scholar in Chemical Engineering. He earned his doctorate in chemical physics from Columbia University and bachelors degrees in chemistry and mathematics from the University of Hawaii. Using a combination of cutting-edge computer simulations and analytical theory, his research revolves around developing novel techniques to manipulate, direct, and self-assemble matter at the micro-scale. He is interested in understanding how colloidal active matter can be used as a tool to engineer the microscopic for applications such as targeted drug delivery to specific cells, the clean-up and neutralization of environmental pollutants, self-propelled micro-tools,  and the massive parallel assembly of microscopic structures. A significant thrust of his research is developing advanced computational methods that provide a consistent and faithful description of colloidal systems with the highest level of computational efficiency. 

Anna Wuttig, Ph.D.
National Institutes of Health Postdoctoral Fellow
University of California, Berkeley
Host: Professor Lawrence Que Jr.

Abstract

Mechanism-Guided Control of Electrocatalytic Reaction Selectivity

Catalysis driven by electricity integrates renewable energy sources in the synthesis of products across the chemical value chain. Irrespective of the desired reaction, selective and efficient electrochemical transformations require the management of electrons and protons. I highlight two reactions in which we utilize a mechanistic approach to elucidate the role of controlled proton or electron transfer in directing product selectivity. In the electrocatalytic reduction of CO₂ to fuels, electrokinetic and spectroscopic studies reveal the disparate proton-coupling requirements for CO₂ versus H⁺ activation, demonstrating that impeding interfacial proton transfer to the electroactive surface is an effective strategy for selective catalysis. In reductive cyclizations catalyzed by molecular Ni catalysts, synthetic and electroanalytical studies disclose the electron transfer requirements to electrogenerate synthetically tractable radical intermediates, establishing how ligand design drives selective radical processes.

Anna Wuttig, Ph.D.

Anna Wuttig, Ph.D., is a National Institutes of Health Postdoctoral Fellow at the University of California, Berkeley. She earned her doctorate from the Massachusetts Institute of Technology and her Artium Baccalaureus in chemistry from Princeton University. Her research encompasses exploring synthetic possibilities afforded by electrochemical approaches. She aims to understand how to integrate renewable electricity into chemistry value chains.

Kent J. Griffith, Ph.D.
Postdoctoral Researcher
Northwestern University
Host: Professor Andreas Stein

Abstract

Understanding Intrinsically Rapid Electrochemical Charge Storage in Complex Inorganic Oxides

Lithium-ion batteries have enabled the portable electronics revolution of the past three decades. Looking to 2050, the sustainable energy transition will critically depend on advanced electrochemical energy storage materials – lithium-ion and beyond – to relieve our dependence on fossil fuels for transportation and grid-scale power. A limitation of conventional battery materials is their relatively slow charging rate, which is on the order of hours. While the discharge/charge rate and capacity can be tuned by varying the composite electrode structure, mixed ion–electron transport within the active electrode particles represents a fundamental chemical limitation.

In this talk, I will describe how mixed-metal crystallographic shear oxides with topologically frustrated polyhedral arrangements and dense μm-scale particle morphologies can rapidly and reversibly intercalate large quantities of lithium. Multielectron redox, buffered volume expansion, in situ self-doping, and extremely fast lithium transport approaching that of a liquid can lead to high energy density and rate performance. Characterisation of these phenomena will be presented with structural and (electro-)chemical insights from operando X-ray diffraction and multi-edge X-ray absorption spectroscopy, high-resolution neutron diffraction, and solid-state nuclear magnetic resonance spectroscopy. The direct measurement of solid-state lithium diffusion coefficients (D_Li) with pulsed field gradient NMR demonstrates room temperature D_Li values of 10^–12–10^–13 m² s^–1 in these complex oxides, which is several orders-of-magnitude faster than typical electrode materials and corresponds to a characteristic diffusion length of ~10 μm for a 1 minute charge. Materials and mechanisms that enable long-range lithiation in minutes have implications for high-power, fast-charging devices and for broader approaches to electrode design and material discovery.

Kent J. Griffith, Ph.D.

Kent J. Griffith, Ph.D. is a solid-state chemist interested in materials to solve global energy challenges. At Northwestern University, he has several projects related to lithium-ion batteries, 'beyond Li' battery chemistries, and thermoelectrics, working jointly with the Department of Chemistry and the Department of Materials Science and Engineering. His research incorporates advanced characterization methods to obtain atomic-level insights on mechanisms of operation and degradation in functional materials, especially high-rate lithium-ion batteries. In the lab, he synthesizes new materials, conducts electrochemistry, and uses tools including solid-state nuclear magnetic resonance (NMR) spectroscopy and X-ray diffraction. He also regularly visit particle accelerators and nuclear reactors to perform X-ray spectroscopy (XAS, XANES, EXAFS) and high-resolution X-ray and neutron diffraction. Though primarily an experimentalist, he dives into electronic structure calculations to help guide or explain his research and works closely with theorist collaborators.

Griffith completed his doctorate in chemistry at the University of Cambridge and earned his bachelor's degree in chemistry from Indiana University.