Thursday, Feb. 18, 2021, 9:45 a.m. through Thursday, Feb. 18, 2021, 11 a.m.
Professor Lasse Jensen
Department of Chemistry
Pennsylvania State University
Host: Professor Renee Frontiera
Surface-Enhanced Spectroscopy in Inhomogeneous Electric Fields
Over the last few years, we have developed new theories and computational methods for understanding vibrational spectroscopy of molecules near metal surfaces. Specifically, we have developed a new computational toolbox for simulating surface-enhanced vibrational spectroscopy in inhomogeneous electric field. This kind of spectroscopy relies on the strong localized electric near-field at the surface of plasmonic metal nanoparticles. Our work has shown that it is possible to resolve intricate molecule vibrations with atomic resolution, which requires that the near-field is confined to a few Ångstroms. Under these conditions, the traditional selection rules breaks down and simulations are required for understanding the spectroscopy. Here, we will discuss our latest developments in understanding surface-enhanced vibrational spectroscopy in inhomogeneous electric fields.
Professor Jensen's research lies in the field of theoretical chemistry and involves developing new methods for simulations of metal-molecule interactions. Researchers in his group seek to use computer simulations to gain a fundamental understanding of the underlying physics and chemistry. They are particularly interested in understanding the optical properties of molecules at the interface of plasmonic nanomaterials. The theoretical and computational methods developed and applied in our group combine electronic structure theory and electrodynamics to describe light-matter interactions at the nanoscale.
Tuesday, Feb. 23, 2021, 9:45 a.m. through Tuesday, Feb. 23, 2021, 11 a.m.
Professor Eric Schelter
Department of Chemistry
University of Pennsylvania
Host: Valérie Pierre
Fundamental Principles in Coordination Chemistry Applied to Metal Ion Separations for Outcomes in Sustainability
Metals such as gold, palladium, tellurium, lithium, and the rare earths are now pervasive in technology and used regularly in our daily lives. But where do they come from, and how do we get them into pure forms for use in technology? In many cases, mining and purification practices for ‘critical’ metals and extremely harmful for people and the environment. It is therefore attractive to try and reclaim such metals from spent technologies. However, in many cases, chemistry and engineering to recycle specific critical metals is lacking, compared to the cost of obtaining them from primary sources. In this talk, efforts to develop new separations chemistry for recycling critical metals will be presented. Among these, efficient, inter-f-element separations, such as within the rare earths, remain a perennial challenge. We have been interested in triggering element-specific changes, for example through highly specific structural differences, to achieve efficient separations through new thermodynamic modes. And in an orthogonal approach, to express differences in metal complexes through variable rates of some chemical change – a separations chemistry through kinetics. Both methods allow direct connection of coordination chemistry to macroscopic properties for separations. These connections have enabled new modes in solid-liquid extraction to complement solvent extraction for specialized applications. For this talk, our latest results on chelating and redox active ligand frameworks and their applications in thermodynamic and kinetic separations of elements will be presented.
Research projects in Professor Schelter’s group involve inert atmosphere/Schlenk line synthesis of inorganic and organometallic complexes. Rigorous characterization of new compounds is achieved through X-ray crystallography, NMR, FTIR, and UV-Visible absorption spectroscopies, electrochemistry and magnetic susceptibility studies. Current projects are focused on the chemistries and electronic structure effects of the lanthanides, uranium and main group elements.
Professor Schelter joined the faculty at the University of Pennsylvania in 2009. He earned his bachelor’s degree from Michigan Technology University, and his doctorate from Texas A&M University. He was a post-doctoral fellow at the Los Alamos National Laboratory.
Thursday, Feb. 25, 2021, 9:45 a.m. through Thursday, Feb. 25, 2021, 11 a.m.
Professor Lyudmila Slipchenko
Department of Chemistry
Host: Professor Jason Goodpaster
The focus of Professor Slipchenko's research is on the development of theoretical and computational approaches targeting the electronic structure of extended systems such as photosynthetic and fluorescent proteins, molecular solids, polymers, and bulk liquids. Specifically, researchers develop universal force fields, QM/MM (quantum mechanics/molecular mechanics), and fragmentation techniques. These methods are broadly applicable to all areas of science and engineering; the resulting computer codes are implemented in the Q-Chem and GAMESS electronic structure packages. They also use the developed techniques to investigate fundamental aspects of non-covalent interactions and the effect of the environment on electronic structure.
Tuesday, March 2, 2021, 9:45 a.m. through Tuesday, March 2, 2021, 11 a.m.
Professor Valerie Schmidt
Department of Chemistry & Biochemistry
University of California, San Diego
Host: Professor Christopher Douglas
Professor Schmidt's group is primarily focused on the development of new methods and catalysts for chemical synthesis, including unique selectivity of reactive intermediates that contain unpaired electrons to forge new chemical bonds; synthetic methods that intrinsically minimize by-products, waste, and overall energy consumption; and uncovering the physical organic and inorganic properties of research methods in order to harness them for further discovery.
Thursday, March 4, 2021, 9:45 a.m. through Thursday, March 4, 2021, 11 a.m.
Professor Julie A. Kovacs
Department of Chemistry
University of Washington
Host: Professor Lawrence Que Jr.
Professor Julie Kovacs' research program is aimed at determining how cysteinates influence function in non-heme iron enzymes. Non-heme iron enzymes promote important biological reactions, including tumor suppression, the biosynthesis of antibiotics, scavenge reactive oxygen species, and detoxification of heavy metals. However, the mechanisms by which these reactions are carried out are not well understood.
Researchers in Kovacs' lab hope to elucidate the mechanism of oxygen-oxygen bond formation by creating synthetically tunable small molecule analogues to investigate the most prominent theories: the radical coupling (RC) mechanism wherein a MnIV-oxyl radical attacks a bridging oxo; and the nucleophilic attack (AB) mechanism, wherein a hydroxyl group attached to the OEC’s calcium atom attacks a MnV-oxo. They aim to spectroscopically characterize the intermediates formed in these reactions through a variety of methods, including X-ray crystallography, NMR, EPR, mass spectroscopy, X-ray absorption spectroscopies, resonance Raman spectroscopy, and cyclic voltammetry. The insights gained from studying these small molecule analogues will allow better study of the OEC itself, as well as provide information for creation of more effective artificial water oxidizing systems.
Julie Kovacs has been a bioinorganic and inorganic professor a the University of Washington since 1988. She earned her bachelor's degree from Michigan State University, and her doctorate from Harvard University. She also was a post-doctoral fellow at the University of California, Berkeley.
Tuesday, March 9, 2021, 9:45 a.m. through Tuesday, March 9, 2021, 11 a.m.
Danielle Schultz, Ph.D.
Host: Professor Courtney Roberts
Danielle Schultz, Ph.D., is an associate principal scientist in Discovery Process Chemistry at Merck, where she has worked for more than six years. She earned her doctorate from the University of Michigan, and her Bachelor of Science from the University of Wisconsin-La Crosse. She also was a National Institutes of Health post-doctoral fellow at the University of Wisconsin-Madison.
Tuesday, March 16, 2021, 9:45 a.m. through Tuesday, March 16, 2021, 11 a.m.
Professor John Anderson
Department of Chemistry
University of Chicago
Host: Professor Ian Tonks
At the heart of Professor Anderson's research lies the interplay between natural and synthetic systems. Researchers aim to use well-defined synthetic complexes and materials with two main goals: using isolable complexes as models for biological systems, notably as tools to understand some of the fundamental properties that govern enzymatic transformations; and using principles employed by biological systems to develop challenging reactivity or properties in complexes or materials. Other aims include the careful control of spin-state, bi-functional activation of substrates, and the utilization of redox active scaffolds to mediate reactivity and coupling.
Wednesday, March 17, 2021, 4 p.m. through Wednesday, March 17, 2021, 5 p.m.
Professor Caroline Saouma
Department of Chemistry
University of Utah
Host: Professor Connie Lu
Thermodynamic and mechanistic studies of CO2 reduction catalysts
The increase in global energy demands, coupled with growing environmental concerns, necessitates the development of viable technologies to store solar energy. Towards this end, my group is focused on developing efficient catalysts that convert CO2 to CO, methanol or formic acid. My talk will first describe our mechanistic studies on known CO2 hydrogenation catalysts, whereby mechanistic insight is gleaned through thermochemical studies, and allows for tuning the product selectivity. We also have uncovered a unique mechanism for CO2 hydrogenation, whereby CO2 must first bind to the ligand before subsequent reduction occurs. I will then discuss how we have used the same thermochemical approach to study the mechanism of electrocatalytic CO2 reduction in a combined carbon capture & reduction system. Finally, I will present a novel ligand scaffold that, when put on Co, allows for both the hydrogenation of CO2 to formate and the electrochemical reduction of CO2 to formate; this is unique in that no H2 is produced electrocatalytically. The collective work underscores the importance of the effective hydricity as a parameter of interest and in using thermochemical parameters to rationalize and uncover alternative mechanisms. The studies presented are contextualized in developing an understanding of how to rationally design energy-efficient CO2 reduction catalysts.
Caroline Saouma was born in Pittsburgh, PA, and grew up between Boulder, CO, and Lausanne, Switzerland. After visiting National Institute of Standards and Technology as a second grader, she was hooked on science. She went to the Massachusetts Institute of Technology to complete her bachelor’s degree (chemistry, 2005), where she did research with Steve Lippard on developing cisplatin analogues that target specific malignancies. She then went to Caltech to complete her doctorate under the supervision of Jonas Peters, where she investigated iron-mediated reductions of CO2 and N2. Her postdoctoral work with Jim Mayer focused on Proton-Coupled Electron Transfer (PCET) reactions of synthetic FeS clusters and MOFs. She joined the faculty at the University of Utah as an assistant professor in 2014, where her research is focused on mechanistic studies and catalyst design for CO2 reduction. She is the recipient of the National Science Foundation CAREER (2020) and is a Chemical Communications Emerging Investigator (2020). Outside of chemistry, she is an avid athlete; as a graduate student she was training to row with the US national team, and she now enjoys cross country skiing and road biking.
Professor Saouma's research program is focused on developing a fundamental understanding of transition-metal mediated small molecule activation, as it pertains to energy conversion and green synthetic applications. Using motifs found in Nature, researchers in her lab design and develop transition metal complexes that will allow them to test ideas on how to selectively achieve complex multi-e–/multi-H+ chemical transformations at low over-potentials. Topics of current interest include (i) activation of O2 for fuel cell and synthetic applications, and (ii) electrocatalytic CO2 fixation and CO2 reduction to methanol. Detailed reactivity and mechanistic studies will be combined with a wealth of data from spectroscopic and structural techniques to provide insights to these transformations, which will allow for the rational design of functional catalysts.
Thursday, March 18, 2021, 9:45 a.m. through Thursday, March 18, 2021, 11 a.m.
Professor Rebekka Klausen
Department of Chemistry
Johns Hopkins University
Host: Professor Marc Hillmyer
The unifying theme of research in the Klausen research group is the application of rational organic synthesis to advance the frontiers of materials science. Through the atomic-level control provided by bottom-up synthesis, we precisely determine and control materials properties. In particular, researchers focus on carbon and silicon-based materials. Crystalline silicon, the preeminent solid state semiconductor, powers defining modern technologies like integrated circuits and solar cells. Inspired by the structure and properties of Group IV and III-V electronic materials, like silicon, graphene, and h-BN, they explore the synthetic chemistry and materials properties of carbon and silicon molecules, polymers, and other nanomaterials.
Professor Klausen joined the faculty at Johns Hopkins University (JHU) in July 2013. Prior to JHU, she earned her doctorate at Harvard University, and completed post-doctoral work at Columbia University.
Monday, March 29, 2021, 4 p.m. through Monday, March 29, 2021, 5 p.m.
Digital and Geospatial Director
Mapping Prejudice Project
Host: Marianne Meyersohn
Kevin Ehrman-Solberg is one of the co-founders of the Mapping Prejudice Project and is a graduate student in the Department of Geography, Environment and Society at the University of Minnesota. Ehrman-Solberg recently completed his Master of Geographic Information at the University of Minnesota. He masterminds the work of building the database necessary for the Mapping Prejudice maps, massaging the data that volunteers create into points that can be mapped digitally. He has also done the spatial analysis for the project, showing how covenants changed neighborhood demographics and how they laid the groundwork for later redlining and devastating urban renewal projects.
About the Mapping Prejudice Project
"This research is showing what communities of color have known for decades. Structural barriers stopped many people who were not white from buying property and building wealth for most of the last century. In Minneapolis, these restrictions served as powerful obstacles for people of color seeking safe and affordable housing. They also limited access to community resources like parks and schools. Racial covenants dovetailed with redlining and predatory lending practices to depress homeownership rates for African Americans. Contemporary white residents of Minneapolis like to think their city never had formal segregation. But racial covenants did the work of Jim Crow in northern cities like Minneapolis. This history has been willfully forgotten. So we created Mapping Prejudice to shed new light on these historic practices. We cannot address the inequities of the present without an understanding of the past."
Inaugural lecture for the Chemistry Social Justice Lectures Series, a student-led initiative to focus two seminars annually on important social issues.