Past Seminars & Events

Professor Courtney Roberts
Department of Chemistry
University of Minnesota
Abstract

Access to “Inaccessible” Arynes and Redox Chemistry Using Transition Metal Complexes 

Research in the Roberts group involves looking at unsolved problems in organic synthesis through the perspective of organometallic/inorganic chemistry. One main area of interest for the group is the synthesis of heterocycles through aryne intermediates. Despite their useful reactivity, a number of challenges still remain in the use of arynes including problems with regioselectivity and the synthesis of N-heterocyclic arynes. Using fundamental principles of Ni chemistry, our group is the first to be able to access previously “inaccessible” 5-membered heterocyclic arynes for the first time since they were hypothesized to exist 120 years ago. We are also the first group to demonstrate catalyst controlled regioselectivity in arynes, where all previous examples operated under substrate control. Another challenge in organic synthesis lies in alkyl–alkyl cross-coupling. This is due to challenges with oxidative addition and off cycle pathways such as beta-hydride elimination. Our group has pioneered the use of Group 3 metal catalysts supported by redox-active ligands to overcome some of these challenges. Using 10 mol% of a Sc, Y, or Lu tris(amido) catalyst, coupling partners that both have beta-hydrogens can be successfully cross- coupled for the first time using early transition metals. These improvements related to organic synthesis can only be accessed using inorganic/organometallic chemistry.

Courtney Roberts

Prof. Courtney C. Roberts is an assistant professor and the 3M-Alumni Professor of Chemistry and McKnight Land-Grant Professor at the University of Minnesota. She obtained her B.S. in chemistry from Pepperdine University in Los Angeles, CA. She then pursued her graduate studies at the University of North Carolina at Chapel Hill, becoming the first graduate student in the laboratory of Prof. Simon Meek. During graduate school, Courtney developed rhodium olefin hydrofunctionalization catalysts using a new class of ligands called carbodicarbenes. After completing her Ph.D. in 2016, Courtney became a postdoctoral research fellow in the laboratory of Prof. Melanie Sanford at the University of Michigan where she explored C–H functionalization reactions using high valent Ni. Courtney began her career as an Assistant Professor at the University of Minnesota in the Fall of 2019. The Roberts group focuses on the development of d 0 metal catalysts for alkyl–alkyl cross coupling as well as harnessing heterocyclic aryne intermediates for medicinally relevant building blocks. While at UMN, she has been the recipient of the Amgen Young Investigator Award, a Thieme Chemistry Journal Award, the NSF CAREER Award, the NIH Maximizing Investigators Research Award, ICCC Rising Star Award, the 3M-Alumni Professorship in Chemistry, and McKnight Land-Grant Professorship.

Hosted by Professor Ian Tonks

Professor David R. Williams
Department of Chemistry
Indiana University
Abstract

Inspiration and Discovery in Natural Product Synthesis

The presentation will discuss the generation of ideas, and aspects of strategy that led to experimentation and execution of a route for the total synthesis of cyathin D and related terpenes. Our retrosynthetic analysis is intended to provide a platform for discoveries of new methods. A fusion of ideas and novel applications stemming from the traditions of natural product synthesis will incorporate leading elements of transition-metal catalysis. Stereocontrolled and regiocontrolled transformations require careful attention to detail and a concept for mechanistic understanding of complex reactions.

David R. Williams

David R. Williams received his B.S. degree (Magna Cum Laude, Phi Beta Kappa Honors) at St. Lawrence University (Canton, New York). He went on to graduate studies at the Massachusetts Institute of Technology and was awarded the Ph.D. in organic chemistry in 1976 under the direction of Professor George Büchi. Subsequently, he was awarded the National Institutes of Health Postdoctoral Fellowship for studies at Harvard University with Professor E. J. Corey (Nobel laureate), and also served as an NIH Fellow at Harvard under the mentorship of Professor R. B. Woodward (Nobel laureate). Prof. Williams began his academic career at IU in 1980. His research has resulted in over 160 scholarly publications. To date, 130 graduate students and postdoctoral associates have studied in his laboratories. Prof. Williams’ research interests lie in the development of methodologies and strategies for the total synthesis of biologically active natural products. The Williams’ laboratories have made leading contributions of synthetic chemistry in areas of marine natural products, including macrocycles, antibiotics, and alkaloids. To date, these efforts have described new pathways to approximately 50 natural product syntheses of importance completed as potential therapeutic agents to advance treatments for cancer, as well as other diseases. 

Prof. Williams was named a Fellow of the American Chemical Society in 2024. In addition, he was the recipient of the ACS Ernest Guenther Award in the Chemistry of Natural Products (2018) and was recognized with the ACS Edward Leete Award (2005) for mentorship and scholarship in his research.

Hosted by Professor Chris Douglas

Professor Ambika Bhagi-Damodaran
Department of Chemistry
University of Minnesota
Abstract

Exploring and Engineering Iron Enzymes: Six Years of Bhagi-Damodaran Lab

From respiration to nitrogen fixation, iron-containing enzymes catalyze some of the most critical biological processes. These enzymes exploit their complex protein architecture to manipulate the chemical properties of their iron center and execute a diverse array of biochemical reactions. The Bhagi-Damodaran lab is dedicated to elucidating the structural and mechanistic foundations of iron enzyme function and developing small-molecule discovery and computational protein engineering strategies to optimize their biological capabilities. These enzyme engineering endeavors, while central to biological and inorganic chemistry, hold immense promise for advancing therapeutics and sustainable catalysis. In this seminar, Professor Bhagi-Damodaran will delve into her lab’s research on (A) deciphering the molecular underpinnings of iron enzyme-mediated redox signaling pathways in cells, (B) rationally engineering iron enzymes for precise and adaptable C(sp3)-H functionalization reactions, and (C) redox selectively inhibiting iron enzymes for the development of next-generation antibiotics. This talk will appeal to a broad audience of Biological, Inorganic, Computational, and Analytical Chemists.

Ambika Bhagi-Damodaran

Ambika Bhagi-Damodaran is an Assistant Professor of Chemistry at the University of Minnesota, Twin Cities. Ambika completed her Ph.D. at the University of Illinois, Urbana- Champaign in 2016 focusing on structure- function relations of iron and copper enzymes involved in respiration and denitrification processes. Ambika’s postdoctoral work at the University of California, San Francisco focused on understanding structural basis of protein- protein interactions in an enzymatic cancer drug target. In 2018, Ambika started her independent career at the University of Minnesota. She leads the Bhagi-Damodaran lab which focuses on engineering metalloenzymes towards sustainable catalysis and new therapeutics. Throughout her career, Ambika has received numerous awards. Most notable amongst them are the Young Investigator Award from American Chemical Society, NIH Ruth L. Kirschstein postdoctoral fellowship, Faculty for the Future award from Schlumberger foundation, NIH MIRA award, NSF CAREER Award, 3M NTF Award, RCSA Cottrell Scholar Award, McKnight Land-Grant Professorship, and ACS Jon Sessler Award for Emerging Leaders in Bioinorganic and Medicinal Inorganic Chemistry.

Hosted by Professor Mark Distefano

Professor Wayne Gladfelter
Department of Chemistry
University of Minnesota
Abstract

Metal Oxide Nanocrystals as Acceptors in Excited State Electron Transfer Reactions

In photovoltaic devices solar photons are used to separate positive and negative charges for the generation of electrical current. Solid state metal oxides play an important role as electron transport materials in most organic, polymeric, quantum dot, perovskite and dye-sensitized solar cells. In dye-sensitized solar cells the metal oxide, typically a nanocrystalline film of titanium dioxide, zinc oxide or tin dioxide, also plays a central role in the charge separation step. To minimize the complicated kinetics of the charge separation reaction in nanocrystalline metal oxide films, we use monodisperse nanocrystals as a uniform platform to serve as the electron acceptor. This has the added advantage of allowing the electron transfer kinetics to be evaluated in solution. Marcus theory teaches that the electron transfer rate constant depends on the free energy differences between the donor and acceptor states, the electronic coupling between the donor and acceptor and the reorganization energy. In the course of this study a series of fluorescent organic and metal organic dyes were synthesized. Each included an anchor, typically a carboxylic acid, that provided a means for attachment of the dye to the nanocrystal surface. The dye adsorption characteristics were evaluated using a Langmuir adsorption model which revealed the maximum number of dyes that bind to a nanocrystal as well as the binding constant. Cyclic voltammetry and spectroelectrochemical measurements established the energy and spectrum of the one- electron oxidized dye, which were critical for interpreting the spectral changes measured using ultrafast pump probe spectroscopy. Zinc oxide and indium oxide nanocrystals were used as the electron acceptors. Variation of the ZnO nanocrystal diameter allowed the evaluation of the effects of quantum confinement and estimation of the reorganization energy. Variation of the dyes’ molecular structure allowed us to map excited state electron transfer rate constant changes attributed to the difference in the electronic coupling and free energy change between the excited state of the donor and the metal oxide nanocrystals.

Wayne Gladfelter

• BS 1975 Colorado School of Mines; Advisor: Dean W. Dickerhoof
• PhD 1978 Pennsylvania State University; Advisor: Gregory L. Geoffroy
• NSF Postdoc 1978-9 Caltech; Advisor Harry B. Gray

Professor Takahiko Kojima
Department of Chemistry
University of Tsukuba, Japan
Abstract

Selective Chemical Conversion Using Metal Complexes Based on Proton-Coupled Electron Transfer

Selective conversion of abundant natural feedstock and C1 resources such as CH₄ and CO₂ to useful compounds has been recognized to be one of most important tasks of chemistry.¹ In this seminar, catalytic oxidation of C-H bonds by high-valent metal-oxo complexes and photocatalytic CO₂ reduction will be presented as main topics. After briefly introducing our effort in oxidation reactions using Ru complexes based on proton- coupled electron transfer (PCET),² selective CH₄ oxidation to CH₃OH using Fe complexes will be also described under a “catch-and-release” strategy in aqueous medium.^3,4 As for CO₂ reduction, inspired by a Ni-containing enzyme, highly selective and efficient conversion of CO₂ to CO has been achieved using Ni complexes as catalysts under visible-light irradiation.^5,6 In addition, a self-photosensitizing dinuclear Ru catalyst will be introduced as a good catalyst for almost stoichiometric CO₂-to-CO conversion.⁷ In this presentation, it will be emphasized that appropriate arrangement of second coordination sphere of metal complexes should be important for achieving selective and efficient chemical conversion.

Takahiko Kojima

Takahiko Kojima was born in Nagoya, Japan, in 1962 and earned a bachelor’s degree and Ph.D. degree in coordination chemistry under the supervision of Prof. Sadao Yoshikawa in 1986 and Prof. Masanobu Hidai in 1991 at The University of Tokyo, respectively. After working as a postdoctoral associate in Prof. Lawrence Que, Jr.’s group from 1991 to 1993 at University of Minnesota in USA, he became an assistant professor of Chemistry Department in Kyushu University in 1994. He moved to Department of Material and Life Science, Osaka University, as an associate professor of Prof. Shunichi Fukuzumi’s group in 2005. Since 2008, he has been serving as a full professor of Department of Chemistry, University of Tsukuba. He was awarded the Chemical Society of Japan Award for Creative work for 2019. His research interest includes proton-coupled electron transfer in metal complexes, oxidation catalysis, artificial photosynthesis, redox and photochemical reactivity of nonplanar porphyrinoids.

References

1. T. Ishizuka, T. Kojima, Acc. Chem. Res. 2024, ASAP.
2. T. Kojima, Bull. Chem. Soc. Jpn. 2020, 93, 1571-1582.
3. H. Fujisaki, T. Ishizuka, H. Kotani, Y. Shiota, K. Yoshizawa, T. Kojima, Nature 2023, 616, 476-481.
4. H. Fujisaki, T. Ishizuka, H. Kotani, T. Kojima, ACS Catal. 2024, 14, 2609-2619.
5. D. Hong, Y. Tsukakoshi, H. Kotani, T. Ishizuka, T. Kojima, J. Am. Chem. Soc. 2017,139, 6538-6541.
6. D. Hong, T. Kawanishi, Y. Tsukakoshi, H. Kotani, T. Ishizuka, T. Kojima, J. Am. Chem. Soc. 2019, 141, 20309-20317.
7. T. Ishizuka, A. Hosokawa, T. Kawanishi, H. Kotani, Y. Zhi, T. Kojima, J. Am.Chem. Soc. 2023, 145, 23196-23204.

Hosted by Professor Jessica Hoover

Psychological Safety: FROM Understanding & Embracing TO Action

Shari L. Robinson will return to the Department of Chemistry to dive deeper into the topic of psychological safety. This is a follow-up talk to Shari's January 2024 presentation, Understanding and embracing an environment of psychological safety.

Shari L. Robinson joined the University of Minnesota as the inaugural DEI Director for CCAPS (College of Continuing and Professional Studies) in April 2023. She comes to us after moving to the Twin Cities in 2020 and after a 2-year faculty appointment at the University of St. Thomas. Shari is a social worker and a linguistic anthropologist by training with over two decades of experience as a faculty member developing and teaching social work courses and professional development trainings on aging, anti-Blackness, anti-racism, queer/trans studies, race, social justice and whiteness, as well as cultural anthropology courses at many colleges and universities across Michigan, Massachusetts, and now Minnesota. Prior to her career in higher education, Shari had over a decade of professional and clinical practice experience working solely with older adults. In her spare, but rare time, Shari enjoys spending time with her many house plants and fish tanks; reading all things Afro-futurism and YA literature which features Black girl mermaids; watching Star Trek runs; cooking (and eating!) all types of food; walking around the many Minnesota lakes, as well as enjoying the rich cultural scene in the Twin Cities and traveling to warm places with her spouse, Jackie.

Professor James McKone
Department Chemical Engineering and Chemistry
University of Pittsburgh
Abstract

From Molecules to Materials: comparative studies of proton-electron transfer in redox-active tungsten oxides

Hydrogen transfer reactions are integral to energy conversion and chemical transformations in natural and built environments. Unsurprisingly, then, these types of reactions are actively studied by many sub-disciplinary communities in the chemical sciences, each with their own preferred methods and heuristics. For example, inorganic coordination compounds that perform H-transfer catalysis are often invoked as compositionally precise and highly characterizable models of solid catalysts. However, relatively little work has been done to date to explore the limits of this analogy. To this effect, our research group is collaborating with experts in coordination chemistry, quantum chemistry, surface science, and materials science to better understand the reactivity of protons and electrons across what we term the “molecules-to- materials design continuum.” In this presentation, I will summarize recent and ongoing work we are pursuing to directly compare the dynamics of hydrogen transfer in molecular polyoxotungstate clusters and tungsten-oxide nanomaterials. First, I will discuss independent studies to elucidate mechanisms for proton activation and H–H bond formation in phosphotungstates and tungsten oxide nanomaterials. Then I will cover recent and ongoing work to use molecular and extended tungsten oxides to mediate hydrogen transfers to organo-nitrogen compounds. Finally, I will briefly summarize work in progress to use thermal treatments to convert polyoxotungstates into extended solid catalysts, which enables “apples-to-apples” comparisons of oxygen reduction electrocatalysis for molecular and extended oxides under identical conditions.

James McKone

Dr. James R. McKone is an associate professor of chemical engineering and chemistry at the University of Pittsburgh. He holds a bachelor’s degree in chemistry and music from Saint Olaf College and a PhD in chemistry from the California Institute of Technology. Prior to joining the faculty at Pitt in 2016, he was a DOE EERE postdoctoral researcher in the Department of Chemistry and Chemical Biology at Cornell University. Prof. McKone’s research group studies fundamentals and applications of electrochemistry and inorganic materials chemistry, guided by the imperative mission of global decarbonization within the 21st century. His awards and honors include Caltech’s Milton and Francis Clauser Prize (2013), RCSA’s Scialog faculty fellowship in advanced energy storage (2017), and the Beckman Young Investigator Award from the Arnold and Mabel Beckman Foundation (2020). Currently on sabbatical leave as the George T. Piercy Visiting Professor at the University of Minnesota. Prof. McKone resides in Minneapolis with his wife, Kirsten, and two children, Matilda and Eleanor.

Hosted by Professor Ian Tonks

Professor Robert S. Paton
Department of Chemistry
Colorado State University
Abstract

Data-driven predictions of organic reactivity and selectivity

Quantum chemical models of reaction mechanism and selectivity provide a powerful tool to explain the outcome of laboratory experiments. However, since many reactions involve several steps and multiple conformers, the computational expense of QM approaches often prevent their application to predict reaction outcomes more broadly. Surrogate machine-learning models with quantum chemical accuracy at a fraction of the computational cost are set to transform the accessibility of computational predictions of reactivity and selectivity. I will discuss machine learning efforts utilizing knowledge and data from QM studies to generate surrogate models for the large-scale prediction of various atomic and molecular properties. We have developed graph neural networks to predict computational and experimental observables such as spin density, chemical shift, thermochemistry and reactivity. In this talk I discuss the performance of these models in high-throughput predictions of reactivity and selectivity of heteroaromatics and in goal- directed molecular optimization of stable organic radicals, along with strategies to improve model transferability.

Robert Paton

Dr. Robert Paton is a Professor of Chemistry and the inaugural holder of the Marshall Fixman and Branka Ladanyi Professorship at Colorado State University. Research in the Paton group is focused on the development and application of computational tools to accelerate chemical discovery. Paton has received the Harrison-Meldola Medal of the Royal Society of Chemistry (RSC), an Outstanding Junior Faculty Award from the ACS Computers in Chemistry Division, the Silver Jubilee Prize of the Molecular Graphics and Modeling Society and is a Fellow of the RSC. The Paton group enjoy collaborative research and are members of the NSF Center for Computer- Assisted Synthesis (C-CAS), the NSF Molecular Maker Lab Institute (MMLI), and the Center for Sustainable Photoredox Catalysis.

Hosted by Suman Bhaumik

Professor Mona Minkara
Department of Bioengineering
Northeastern University
Abstract

Building the COMBINE Lab: Breaking Barriers as a Blind Chemist

In this talk, Mona Minkara, an assistant professor of Bioengineering at Northeastern University, shares the story behind building the Minkara Computational Modeling for BioInterface Engineering (COMBINE) Laboratory. As a blind chemist, Mona faced challenges and overcame internalized ableism to see her blindness as an asset in the lab’s work. She emphasizes the importance of combining diverse perspectives in science to solve new problems and advocates for disability inclusion in STEM. Her story challenges us to reflect on our biases and recognize the importance of creating inclusive spaces and striving for equitable opportunities for all. 

Throughout her academic journey, Mona navigated the complexities of securing the necessary accommodations for her education and selecting a graduate school that offered the support she needed. Her mentors played a significant role in helping her overcome internalized ableism and see her blindness as an unseen advantage. This perspective has been a driving force in her work. Mona’s story asks us to reflect on how we can work together to break down barriers, and acknowledges there are still barriers to break – we still need to make the results of scientific research and its literature accessible to all people.

Mona Minkara

Dr. Minkara’s research uses a variety of methods from computational chemistry that she has employed throughout her academic career. While pursuing her BA in Chemistry at Wellesley College, Dr. Minkara worked with Dr. Mala Radhankrishnan, where she used computational methods to explore the binding of drugs to HIV-1 Reverse Transcriptase. After completing her BA in 2009, Dr. Minkara spent a year conducting research at Wellesley under a Howard Hughes Medical Institute Research Grant. In 2010, she began her graduate studies at the University of Florida supported by a National Science Foundation Graduate Research Fellowship. Under her co- advisors, Dr. Kenneth M. Merz Jr. and Dr. Erik Deumens, she focused on using molecular dynamics simulations to design a new inhibitor for Helicobacter pylori urease, an enzyme that helps bacteria survive in the stomach, and in 2015, she received her PhD in Chemistry. She then joined Dr. J. Ilja Siepmann’s lab as a post-doc at the University of Minnesota Twin Cities Chemical Theory Center. In this role, Dr. Minkara used Monte Carlo simulations to explore the interfacial properties of surfactants, the surface tension of water, and the miscibility gap of supercritical fluids.

Hosted by Professor Alexander Umanzor

Professor Mona Minkara
Department of Bioengineering
Northeastern University
Abstract

Unlocking the Secrets of Breath and Defense: Surfactant Proteins’ Role in Lung Health and Fighting Disease

In this talk, we explore the impact of Surfactant Proteins B (SP- B) and D (SP-D) on pulmonary function and immune defense, using computational techniques. Our findings highlight the dynamic structural properties of SP-B, essential for breathing. We employed homology modeling based on the crystallized Mini B structure and the saposin family of proteins to develop a computational model of SP-B. Molecular dynamics simulations were then employed on both open and closed states of SP-B in hydrophilic and hydrophobic environments, simulating conditions found within the alveoli. Our research provides insight into SP-B’s conformational stability and interactions under various alveolar conditions, elucidating its adaptation to different environments and enhancing our knowledge of its structure-function relationships and impact on breathing. Additionally, we investigated SP-D’s antiviral mechanisms against Influenza A, revealing how its double mutant variant (Asp325Ala and Arg343Val) exhibits improved antiviral efficacy. We used full-atomistic molecular dynamics simulations with microsecond trajectories to explore the molecular mechanism of these mutations on SP-D’s ability to bind the viral glycan trimannose as a model. This work deepens our understanding of surfactant protein dynamics and suggests new avenues for therapeutic development against pulmonary diseases and viral infections.

Mona Minkara

Dr. Minkara’s research uses a variety of methods from computational chemistry that she has employed throughout her academic career. While pursuing her BA in Chemistry at Wellesley College, Dr. Minkara worked with Dr. Mala Radhankrishnan, where she used computational methods to explore the binding of drugs to HIV-1 Reverse Transcriptase. After completing her BA in 2009, Dr. Minkara spent a year conducting research at Wellesley under a Howard Hughes Medical Institute Research Grant. In 2010, she began her graduate studies at the University of Florida supported by a National Science Foundation Graduate Research Fellowship. Under her co- advisors, Dr. Kenneth M. Merz Jr. and Dr. Erik Deumens, she focused on using molecular dynamics simulations to design a new inhibitor for Helicobacter pylori urease, an enzyme that helps bacteria survive in the stomach, and in 2015, she received her PhD in Chemistry. She then joined Dr. J. Ilja Siepmann’s lab as a post-doc at the University of Minnesota Twin Cities Chemical Theory Center. In this role, Dr. Minkara used Monte Carlo simulations to explore the interfacial properties of surfactants, the surface tension of water, and the miscibility gap of supercritical fluids.

Hosted by Professor Ilja Siepmann