Past Seminars & Events

Kolthoff Lecture #1
Professor Omar Yaghi
Department of Chemistry
University of California, Berkeley
Host: Professor Theresa Reineke

Abstract

Reticular Chemistry of Metal-Organic Frameworks

Linking of molecular building blocks by strong bonds into crystalline extended structures (reticular chemistry) has resulted in metal-organic frameworks and made available precisely designed infinite 2D and 3D materials. The challenges and solutions to making crystalline, permanently porous frameworks, and the ‘grammar’ of linking organic and inorganic building blocks by strong bonds will be described. The resulting structures encompass space within which molecules can be further manipulated and controlled, leading to excellent catalysts, carbon capture and conversion to fuels, and in general, new conceptual advances in carrying out covalent chemistry beyond molecules.

Research

Professor Omar Yaghi's work encompasses the synthesis, structure and properties of inorganic and organic compounds and the design and construction of new crystalline materials. He is widely known for pioneering several extensive classes of new materials termed metal-organic frameworks, covalent organic frameworks, and zeolitic imidazolate frameworks. These materials have the highest surface areas known to date, making them useful in clean energy storage and generation. Specifically, applications of his materials are found in the storage and separation of hydrogen, methane, and carbon dioxide, and in clean water production and delivery, supercapacitor devices, proton and electron conductive systems. The building block approach he developed has led to an exponential growth in the creation of new materials having a diversity and multiplicity previously unknown in chemistry. He termed this field 'Reticular Chemistry' and defines it as stitching molecular building blocks into extended structures by strong bonds.

Professor Yaghi

Professor Yaghi received his Bachelor of Science degree from State University of New York-Albany, and doctorate from the University of Illinois-Urbana. He was a National Science Foundation Post-doctoral fellow at Harvard University. He has been on the faculties of Arizona State University, University of Michigan, and UCLA. He is currently the James and Neeltje Tretter Chair Professor of Chemistry at the University of California, Berkeley, and a senior faculty scientist at Lawrence Berkeley National Laboratory. He is the founding director of the Berkeley Global Science Institute. He is also co-director of the Kavli Energy NanoScience Institute, and the California Research Alliance by BASF.

Kolthoff Lectureship in Chemistry

Izaak Maurits Kolthoff was born on February 11, 1894, in Almelo, Holland. He died on March 4, 1993, in St. Paul, Minnesota. In 1911, he entered the University of Utrecht, Holland. He published his first paper on acid titrations in 1915. On the basis of his world-renowned reputation, he was invited to join the faculty of the University of Minnesota’s Department of Chemistry in 1927. By the time of his retirement from the University in 1962, he had published approximately 800 papers. He continued to publish approximately 150 more papers until his health failed. His research, covering approximately a dozen areas of chemistry, was recognized by many medals and memberships in learned societies throughout the world, including the National Academy of Sciences and the Nichols Medal of the American Chemical Society. Best known to the general public is his work on synthetic rubber. During World War II, the government established a comprehensive research program at major industrial companies and several universities, including Minnesota. Kolthoff quickly assembled a large research group and made major contributions to the program. Many of Kolthoff’s graduate students went on to successful careers in industry and academic life and, in turn, trained many more. In 1982, it was estimated that approximately 1,100 Ph.D. holders could trace their scientific roots to Kolthoff. When the American Chemical Society inaugurated an award for excellence in 1983, he was the first recipient.

Professor Nandini Ananth
Department of Chemistry & Chemical Biology
Cornell University
Host: Professor Aaron Massari

Abstract

 A Study of Singlet Fission in Bipentacenes

We investigate the mechanisms of Singlet Fission (SF), a phenomenon where an initial photo-excited singlet state spontaneously evolves into a correlated triplet state that can subsequently decorrelate into two triplets. We probe different aspects SF in bipentacenes through both high-level electronic structure studies and simple semi-empirical theories to arrive at rules for identifying SF-active chromophores that absorb intensely in the visible region. Further, we study the recombination rates of the correlated triplet state produced by SF using a new, singularity-free formulation for nonradiative rates. We also show that it is possible to identify key vibronic modes in the recombination process. Finally, we discuss the real-time dynamic methods we have developed to enable atomistic simulations of SF.

Professor Ananth

Professor Ananth's group seeks to understand the molecular origin of chemical selectivity in natural and synthetic systems using theoretical simulation techniques derived from the principles of quantum and classical mechanics. Research interests include:

• Developing semiclassical and path-integral based model dynamics to simulate interesting chemistry in the condensed-phase.
• Developing approximate methods for quantum dynamics that are able to incorporate quantum effects like zero-point energy, tunneling, and coherence and to describe electronically nonadiabatic processes, while retaining the favorable scaling in computational cost with system size exhibited by classical molecular dynamics simulations.
• Understanding the molecular origin of chemical selectivity in natural and synthetic systems.
• Investigating exciton chemistry in organic photovoltaics, multi-electron chemistry in tri-metal-center transition metal complexes, and vibrationally promoted hot-electron chemistry in reactions at metal surfaces.

Goals are to use a combination of theory, electronic structure, and quantum dynamics to 1) uncover the detailed mechanisms of novel charge and energy transfer phenomena, 2) identify productive reaction pathways/intermediates as well as competing loss mechanisms, 3) isolate significant factors, such as chemical environment, relative geometries, and temperature that determine dominant pathways, 4) construct experimentally verifiable hypotheses to enhance charge/energy transport properties of specific materials, and 5) build a database of transferable design principles that can be used predictively in the development of novel materials.

Professor Ananth

Nandini Ananth was born in Chennai, India. She attended Stella Maris College in Chennai, and graduated with a bachelor's degree in chemistry. She then joined the master's program in chemistry at the Indian Institute of Technology Madras. Here she developed a strong interest in quantum mechanics and carried out research on implementing logic gates for quantum computing using Nuclear Magnetic Resonance. During this time, she also received a Summer Research Fellowship from the Jawaharlal Nehru Center for Advanced Scientific Research and was introduced to semiclassical dynamics at the Indian Institute of Science, Bangalore. This further solidified her interest in theoretical chemistry and chemical dynamics. Ananth moved to the United States to pursue doctoral research at the University of California, Berkeley, working on developing semiclassical methods to model quantum dynamical behavior in complex chemical reactions. Upon graduation, she accepted a position as post-doctoral scholar at the California Institute of Technology, Pasadena, where her research focused on developing path-integral methods for the simulation of electronically nonadiabatic processes in the condensed phase. She joined the faculty of the Department of Chemistry and Chemical Biology at Cornell University in 2012.

Professor Francesco Evangelista
Department of Chemistry
Emory University

Abstract

Accelerating Quantum Chemistry with Quantum Computers

An outstanding challenge in modern electronic structure theory is simulating chemistry problems that involve open-shell species, such as bond-breaking reactions, photochemical processes, transition metal catalysis, and molecular magnetism. A common feature of all of these problems is the emergence of strong electron correlation effects or quantum mechanical entanglement. Modeling strong correlation is considered a hard problem since, in the most general case, it has a computational cost that scales exponentially with the number of electrons. Quantum computation offers an intriguing approach to accelerate the simulation of strongly correlated electrons. With sustained progress in quantum device engineering, there is a realistic expectation that medium-sized quantum computers (100-200 qubits) will be available in the near future. These devices could enable computations on systems that are classically intractable and open up new applications of computational chemistry. This talk will give an overview of quantum computing approaches for quantum chemistry and describe my group's efforts to develop hybrid quantum-classical methods that combine renormalization group theory and quantum computing.

Professor Evangelista

Professor Evangelista's theoretical chemistry research focus is the development of new electronic structure methods to address chemical phenomena that are not well understood. Having a predilection for rigorous theoretical approaches that follow from first principles, his research group is particularly fond of many-body methods (e.g. coupled cluster theory), but doesn't shy away from density functional theory.

Evangelista earned his doctorate in chemistry from the University of Georgia, his master's in physical chemistry from the University of Pisa, and his undergraduate degree from the Scuola Normale Superiore di Pisa. He also was an Alexander von Humboldt Junior Fellow in Mainz, Germany, and a post-doctoral associate at Yale University. He has been a professor at Emory University since 2013.

Professor Aaron Leconte
W.M. Keck Science Department
Claremont McKenna College
Host: Professor William Pomerantz

Abstract

Using biochemistry and evolution to improve Taq DNA polymerase and Firefly Luciferase

My research group seeks to leverage biochemical characterization and protein engineering to better understand and optimize protein function.  We are currently actively working on two systems, both of which will be discussed. 

We are interested in developing Taq DNA polymerase mutants that are able to synthesize nuclease-resistant forms of modified DNA, which has applications in clinical diagnostics and aptamer technologies.  We have focused on using commercially available substrates and attempting to develop robust, accessible, accurate M-DNA synthesis and reverse transcription reactions.  Our best mutant M-DNA polymerases are able to synthesize long M-DNAs in less than ten minutes; the M-DNA can be reverse transcribed and amplified using entirely commercial reagents in less than an hour. 

We are also developing luciferases for use in multi-component imaging, in collaboration with Prof. Jennifer Prescher (UC-Irvine).  We have used bioinformatics to rapidly identify mutant luciferases with improved function in substrate resolved multi-component imaging applications, and we are currently developing deep mutational scanning approaches to luciferase biochemistry. 

The work that will be described has been performed entirely by undergraduates at The Claremont Colleges, and some of it has been integrated into course-based undergraduate research experiences.  I will highlight the unique opportunities and challenges in this area as well.

Professor Leconte

Professor Leconte earned his bachelor's degree from Carleton College and his doctorate from the Scripps Research Institute. He was a post-doctoral fellow at Harvard University.

Professor Heather Allen
Department of Chemistry & Biochemistry
Ohio State University
Host: Professor Renee Frontiera

Abstract

Interfacial Aqueous Organization and Electric Fields Generated from Chemical Composition

Marine and continental atmospheric aerosol, ocean surfaces, surfaces of the lung, biomembranes, and aqueous interfaces of materials, these interfaces have one thing in common - WATER. This unique molecule plays an important role in the structure of environmental, biological, and material interfaces, and can drive interfacial chemistry in sometimes subtle ways. Water at the air-water interface organizes and facilitates the surface adsorption of other molecular and ionic species. In studies presented, the hydration of surface molecules is evident by spectroscopic signatures using vibrational sum frequency generation (SFG) and infrared reflection absorption (IRRA) spectroscopies. Brewster angle microscopy (BAM) is also used to study macroscopic aggregation, and surface potentiometry is used to reveal the inherent electric field and net dipole perpendicular to and at the water’s surface. I will present studies of salts and lipids, interfacial binding and inherent structure of aqueous interfaces, prior and recent work in our lab. Water has preferred orientations such that free OH oscillators are persistent at the surface, breaking the hydrogen bonding structure of the 3D liquid. Complexation and binding motifs are driven by different rules at the liquid water-vapor interface. Studies on guanidinium surface-anchored receptor binding with phosphate, sulfate, and chloride will be presented. I’ll also present our newest work on applied electric fields to control organization of alcohols, fatty acids, sodium dodecyl sulfate, and ions such as potassium thiocyanate.

Professor Allen

Professor Allen received her bachelor's degree in chemistry from Saddleback, and her doctorate in physical chemistry from the University of California, Irvine. She continued her post-doctoral studies at the University of Oregon. She began her professorial career at Ohio State in 2000, and has since been recognized for many research accomplishments: Research Innovation Award from Research Corp., National Science Foundation CAREER Award, Beckman Young Investigator Award, Alfred P. Sloan Research Fellow Award, Camille Dreyfus Teacher-Scholar Award, Fellow of the American Association for the Advancement of Science, Ohio State Distinguished Scholar Award, and the Alexander von Humboldt Research Award from Germany. In addition, Professor Allen has been recognized for several mentoring awards over the years including the Ohio State Office of Minority Affairs Mentor Award, an Empowered Woman Award from the City of Columbus, and the American Chemical Society National Award for Encouraging Women into Careers in the Chemical Sciences.

Professor Allen's research specialization is in molecular organization, ion pairing, and hydration at aqueous interfaces. Aqueous surfaces are of particular interest with emphasis on understanding surface structure. Investigations of molecular organization and orientation, and chemical reaction mechanisms at gas - liquid, gas - solid, and liquid - solid interfaces are of interest. Cell membranes, atmospheric aerosols, cloud microdroplets, and geochemical systems are interfacial systems that can be studied using vibrational spectroscopic methods, and the Allen research group utilizes and designs optical spectroscopic instruments to this end. To understand the molecular-level details of an interface, state-of-the-art nonlinear optical technologies that utilize ultra-fast femto and picosecond laser pulses are necessary. Surface vibrational sum frequency generation spectroscopy, broadband and scanning technologies, are used by Professor Allen's researchers to elucidate interfacial chemistry. 

Professor Danielle Dube
Department of Chemistry
Bowdoin College
Host: Professor Erin Carlson

Abstract

Chemical tools to discover and target glycoproteins on pathogenic bacteria 

The bacterial cell wall is a quintessential drug target due to its critical role in colonization of the host, pathogen survival, and immune evasion. The dense cell wall glycocalyx contains distinctive monosaccharides that are absent from human cells, and proper assembly of monosaccharides into higher-order glycans is critical for bacterial fitness and pathogenesis. However, the systematic study and inhibition of bacterial glycosylation enzymes remains challenging. Bacteria produce glycans containing rare deoxy amino sugars refractory to traditional glycan analysis,  complicating the study of bacterial glycans and the creation of glycosylation inhibitors. Thus, the development of chemical tools that label bacterial glycans is a crucial step toward discovering and targeting these biomolecules. This seminar will describe how metabolic glycan labeling – which exploits carbohydrate biosynthetic pathways to install unnatural sugars bearing chemical reporters into cellular glycans – has facilitated the studying and targeting of glycoproteins on pathogenic bacteria. In particular, I will describe how this method enabled the discovery of glycoproteins in the gastric pathogen Helicobacter pylori, our recent expansion of this methodology to a range of pathogenic and symbiotic bacterial species, and our development of metabolic inhibitors of glycan biosynthesis to inactivate bacterial pathogens. This work sets the stage to refine our knowledge of the glycan repertoire in diverse bacteria and to disarm bacterial based on their distinctive glycan coating, ultimately providing a platform for the development of novel, narrow-spectrum antibiotics to treat infectious disease. 

Professor Dube

Recent efforts in Professor Dube's laboratory have focused on the pathogenic bacterium Helicobacter pylori, which is the leading cause of duodenal ulcers and stomach cancer worldwide.  Researchers are taking a metabolic labeling-based approach to study H. pylori sugar-coated proteins and to target H. pylori based on its unique sugars. They are pursuing a series of parallel projects that seek to: 

• structurally characterize H. pylori’s distinctive sugars;
• explore the role of these sugars in causing disease;
• identify the genes responsible for their biosynthesis;
• validate H. pylori’s sugars as potential drug targets;
• create inhibitors of bacterial glycan biosynthesis; and
• develop targeted antibiotics that, like smart-bombs or guided missiles, seek out and react with H. pylori’s sugars, leading to selective destruction of H. pylori cells without destroying beneficial bacteria 

Kevin Ehrman-Solberg
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.

Danielle Schultz, Ph.D.
Merck
Host: Professor Courtney Roberts

Utilizing high-throughput experimentation to catalyze diverse chemistry and collaborations within and outside of Merck

Current examples will be discussed that highlight how approaching catalysis through high-throughput experimentation (HTE) has addressed several synthetic challenges that have occurred during pharmaceutical development at Merck. Emphasis will be given towards recently published methodologies that focus on the direct functionalization of sp3 C-H bonds via decatungstate photocatalysis and Ni-catalyzed C-H arylation. These methodologies were the result of strong academic-industrial collaborations that were ultimately enabled with HTE.

Danielle Schultz, Ph.D.

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.

Professor Rebekka Klausen
Department of Chemistry
Johns Hopkins University
Host: Professor Marc Hillmyer

Abstract

Fragments of Crystalline Silicon via Target-Oriented Synthesis

Our experience of daily life includes tools made from the ubiquitous semiconductor silicon: computers, solar cells, and many more. Yet silicon synthesis relies on top-down, high-temperature approaches that yield only the most thermodynamically stable forms of silicon. Uncovering new structure-function space demands a different synthetic vision. This talk will describe the synthesis of molecular and polymeric silanes inspired by the complexity, selectivity, and elegance of target-oriented organic synthesis. Topics include the chemoselective polymerization of novel bifunctional silane monomers, selective preparation of linear and cyclic polycyclosilanes, and the stereocontrolled synthesis of cis- and trans-siladecalin. Approaches to the structural characterization of novel silane architectures will also be discussed.

Professor Klausen

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.

Professor Caroline Saouma
Department of Chemistry
University of Utah
Host: Professor Connie Lu

Abstract

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.

Professor Saouma

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.

Research 

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.