Past Seminars & Events

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Professor Balyn Zaro

Professor Balyn Zaro
Department of Pharmaceutical Chemistry
University of California, San Francisco
Abstract

A Chemical Biology Approach to Innate Immunity

Macrophages regulate how the immune system recognizes self. When a foreign/exhausted cell or pathogen is detected, macrophages engulf and destroy it in a process called phagocytosis. Anti-phagocytic signaling axes, also referred to as ‘don’t eat me’ (DEM) signals, exist between macrophages and other cells. To evade macrophages, healthy cells express DEM signal ligands on their surface. When a DEM ligand engages a DEM receptor on a macrophage, downstream signaling blocks phagocytosis. Four DEM signal ligand- receptor pairs have been discovered, and it is hypothesized that there are others. Dysregulation of DEM signaling has been implicated in cancer, infectious disease, neurodegeneration, and atherosclerosis. In addition to DEM signal ligands, mammalian cells also present ‘eat me’ (EM) ligands, which engage macrophage EM receptors, and are required for phagocytosis. Despite the fundamental role these signals play in basic and disease biology, relatively little is known about the biological mechanisms and consequences of these pathways. Learning to harness and exploit DEM and EM signaling would result in a wave of new biologic discovery in human health and disease. However, highly-selective chemical probes and new specialized chemical proteomic approaches are required. To this end, my lab has developed selective chemical tools and novel proteomic techniques to study macrophage function and host-pathogen interactions. Our new toolkit has lead to discoveries in macrophage function that reveal how we combat disease and may change the way we design immunotherapeutics.

Balyn Zaro

Balyn Zaro, PhD, grew up in California and Connecticut. As an undergraduate researcher at University of Southern California (USC) she studied synthetic methodology and organic chemistry with G.K. Surya Prakash and Nobel laureate George A. Olah. She remained at USC for her PhD studies in chemical biology as the first graduate student in the laboratory of Matthew Pratt, PhD. Her research focused on developing metabolic bioorthogonal chemical reporters to identify and to characterize post-translational modifications of proteins, including glycosylation, acetylation, and ubiquitination. For her postdoctoral studies, she worked in the laboratory of Ben Cravatt, PhD, at Scripps Research Institute in La Jolla, California. There she investigated the metabolism of covalent small molecules using activity-based protein profiling and identified the mechanisms of action of the multiple sclerosis drug Tecfidera® (dimethyl fumarate). She gained additional training with Irving Weissman, MD, at Stanford University School of Medicine in the fields of innate immunity and hematopoiesis before her arrival at UCSF in September 2019.

Hosted by Hannah Lembke

Professor Florence Williams

Professor Florence Williams
Department of Chemistry
University of Iowa
Abstract

Taking Advantage of Strong Boron-Oxygen and Boron-Fluorine Associations for Chemoselective Reactions

The Williams lab has been investigating the utility of highly Lewis acidic boron centers for the activation and cleavage of alkyl ethers and in halogen exchange reactions of trifluoromethylarenes. Such strategies have enabled the targeting of strong C–O bonds and C–F bonds for cleavage in the presence of weaker bonds. These practical methods have important applications in medicinal and agricultural chemistry, as well as in sustainable chemistry development, such as the mild separation of cellulose from lignocellulose – a biopolymer that can provide a renewable source of aromatic chemicals such as vanillin. This talk will examine the development of such boron-mediated methodologies, applications to different modern challenges, and the differential reactivity and behavior of boron trihalide species.

Florence Williams

Florence obtained her Ph. D. at University of California, Irvine working on organometallic catalysis with Prof. Elizabeth Jarvo. After post-doctoral research in chemical biology at Princeton in the lab of Prof. Dorothea Fiedler, Florence began her independent career at University of Alberta in Edmonton, Alberta, Canada and then in 2019 moved to University of Iowa. Her research involves using boron Lewis acids to selectively cleave strong σ bonds, including in complex materials settings, as well as mechanistic investigations of neurotrophic mall molecules that have potential applications in neurodegenerative disease.

Website: www.williamsresearchlab.com

Hosted by Professor Jessica Lamb

Professor Uttam K. Tambar

Professor Uttam K. Tambar
Department of Biochemistry
The University of Texas Southwestern Medical Center
Abstract

Stereoselective Reactions with Feedstock Chemicals

For several decades, chemists have designed new approaches to valuable materials that are economically efficient and environmentally benign. To this end, synthetic chemists have developed new synthetic strategies to access complex molecules from simple, inexpensive, and abundant feedstock chemicals. Our research group explores. new methods in this area. We present recent examples from our laboratory of stereoselective reactions with feedstock chemicals as starting materials. First, we discuss our approach to the stereoselective functionalization of unsaturated hydrocarbons through catalytic pericyclic reactions with chalcogen-based reagents. For example, we have developed enantioselective allylic functionalizations of terminal and internal alkenes. Second, we describe our approach to the enantioselective α-alkylation of aldehydes with amino acid derived alkylating reagents. We have devised a strategy for the activation of pyridinium salts derived from amino acids through the formation of light-activated charge transfer complexes with catalytically generated electron rich chiral enamines derived from aldehyde substrates and a chiral amine catalyst.

Uttam K. Tambar

Uttam Tambar moved from India to New York City in 1982. He received his A.B. degree from Harvard University in 2000, where he conducted research with Professors Cynthia Friend and Stuart Schreiber. He obtained his Ph.D. from the California Institute of Technology in 2006 under the guidance of Professor Brian Stoltz. After he completed his NIH Postdoctoral Fellowship at Columbia University with Professor James Leighton in 2009, Uttam began his independent research career at UT Southwestern Medical Center in Dallas. The Tambar lab is interested in catalysis, natural product synthesis, chemical biology, and medicinal chemistry. Uttam has received several awards, including the Thieme Chemistry Journal Award (2012), Sloan Foundation Research Fellowship (2013), Welch Foundation Norman Hackerman Award in Chemical Research (2019), Arthur C. Cope Scholar Award (2024), and Dallas Home Bartender Tiki Cocktail Prize (2019). Uttam is currently the Bonnie Bell Harding Professor in Biochemistry, Director of Diversity for Biochemistry, and Director of the Organic Chemistry Graduate Program, and Co-Leader of the Simmons Cancer Center’s Chemistry and Cancer Program.

Homepage: www.utsouthwestern.edu/labs/tambar/
Twitter/X: @TambarLab

Hosted by Professor Courtney Roberts

Professor Cathleen Crudden

Professor Cathleen Crudden
Queen’s University
Abstract

N-Heterocyclic Carbenes as Novel Ligands for Nanoparticles and Nanoclusters. Applications in Catalysis, Sensing and Molecular Medicine

NHCs have been documented as strong ligands for single metal atoms in molecular catalysts and as alternative to thiolates on planar metal surfaces. In this final talk, their use as ligands to stabilize atomically precise metal nanoclusters will be described. The structure of the cluster is shown to be strongly influenced by the nature of the NHC. By tuning the NHC structure (backbone and wingtip groups) a variety of new nanoclusters can be prepared. We will present the use of NHC-based nanoclusters with Au₁₀, Au₁₁, Au₁₃, Au₂₄ and Au₂₅ cores, along with recent results on bimetallic cores. The unique properties of these NHC-stabilized clusters, including chirality, photophysical properties, stability and catalytic activity will be addressed.

Cathleen Crudden

Dr. Cathleen Crudden is the A.V. Douglas Distinguished Professor of Chemistry and Canada Research Chair (Tier 1) in metal organic chemistry at Queen’s University in Kingston, Ontario. She holds a Research Professorship at the Institute of Transformative Bio-Molecules (ITbM) in Nagoya, Japan, where she runs a satellite laboratory. She is a Fellow of the Royal Society of Canada, the Chemical Institute of Canada, the Royal Society of Chemistry (UK) and an elected member of the American Association for the Advancement of Science.

Dr. Crudden has made significant impact on diverse areas of science. She described one of the first cross-coupling reactions with chiral, enantiopure molecules that has made considerable impact on the preparation of pharmaceutical compounds. More recently, she has demonstrated the strength and versatility of N-heterocyclic carbene ligands in materials science, showing these ligands to be viable and versatile alternatives to thiolates as ligands for planar metal surfaces, nanoparticles and nanoclusters. This work has been called “game changing,” “elegant,” and “the new gold standard” by experts in the field.

Crudden has served as President of the Canadian Society for Chemistry and Chair of the Chemical Institute of Canada.She is Scientific Director of the Carbon to Metals Coatings Institute (C2MCI) at Queen’s University. She is currently Editor-in-Chief for ACS Catalysis. She has won numerous awards including the 2023 John Polanyi Award, a 2019 Cope Scholar award of the American Chemical Society, the Montreal Medal (2019), and the 2018 Carol Taylor award from the International Precious Metals Institute.

Hosted by Professor Gwen Bailey

Professor Cathleen Crudden

Professor Cathleen Crudden
Queen’s University
Abstract

N-Heterocyclic Carbenes as Novel Ligands on Planar Metal Surfaces–Self Assembled Monolayers, on Surface Ligand Dynamics and Applications in Atomic Layer Deposition

The use of N-heterocyclic carbenes to modify homogeneous metal catalysts is widespread since the high metal–NHC bond strength renders high oxidative and chemical stability to the resulting metal complexes. The use of NHCs to modify metal surfaces has received considerably less attention. We will describe the modification of planar metallic surfaces with NHCs. The nature of the surface overlayer is strongly dependent on the nature of the NHC. The ability of these NHC overlayers to act as small molecule inhibitors for atomic layer deposition processes will be described.

Cathleen Crudden

Join us for a reception at the Coffman Union Campus Club after the seminar, from 5:00 – 7:00 p.m.

Hosted by Professor Gwen Bailey

Professor Cathleen Crudden

Professor Cathleen Crudden
Queen’s University
Abstract

Chirality in the Suzuki- Miyaura Cross-Coupling Reaction

The Suzuki-Miyaura cross-coupling reaction has revolutionized the way chemists make carbon- carbon bonds. However, the method is primarily employed to construct C sp 2 –C sp 2 bonds resulting in flat molecules, which have lower bioactivity and selectivity compared to their three-dimensional counterparts. As these molecules populate pharmaceutical libraries, they inhibit the discovery of valuable new drug candidates. In this talk, our work enabling the introduction of chirality into the Suzuki-Miyaura cross-coupling reaction will be presented, including work using compounds with predetermined chirality, both in the nucleophile or electrophile. Work on the development of novel electrophiles based on sulfones will illustrate the versatility of these novel molecules in cross-coupling chemistry.

Cathleen Crudden

Hosted by Professor Gwen Bailey

Professor W.E. Moerner

Professor W.E. (William E.) Moerner
Departments of Chemistry and Applied Physics (courtesy)
Stanford University
Abstract

The Story of Light and Single Molecules: From Spectroscopy in Solids, to Super-Resolution Nanoscopy in Cells and Beyond

The optical detection of single molecules has provided a new view into the nanoscale. Since ensemble averaging is removed, each single molecule can act as a reporter of not only its position, but also local information about the nearby environment. One key application is super-resolution microscopy, which enables biological objects and material structures to be observed with resolutions down to tens of and below. Examples range from protein superstructures in bacteria to bands in axons to details of the shapes of amyloid fibrils, cell surface sugars, protein superstructures in the primary cilium, and much more. For super-resolution imaging in thick cells, a new tilted light sheet design makes use of optical engineering methods which alter the fundamental way in which a microscope works, providing a simple, useful 3D microscope. Low temperature single-molecule imaging provides much improved localization precision in order to complement cryo-electron tomography studies. Even coronavirus RNA in an infected mammalian cell forms amazing cluster-like structures which are reminiscent of the galaxies from modern telescopes. Combining super-resolution imaging of a static structure with time-dependent 3D tracking of other biomolecules provides a powerful view of cellular dynamics. While not all of these topics can be covered, they serve to illustrate the continuing richness of the field.

W. E. Moerner

W. E. Moerner is the Harry S. Mosher Professor of Chemistry, Applied Physics, Biophysics, and Molecular Imaging at Stanford University. He is a pioneer in the fields of single molecule spectroscopy, super-resolution microscopy, and quantum optics including single-molecule biophysics in cells; nanophotonics of metallic nanoantennas; and photoactive polymer materials. Major milestones include first room-temperature single-molecule source of single photons, 3-D studies of single molecules diffusing in gels, observation of blinking and switching in single GFP molecules, pumping of single molecules with whispering gallery modes of microspheres, and beam fanning and self-pumped phase conjugation in new extremely high gain photorefractive polymers. He is the 2014 Nobel Laureate in Chemistry for the development of super-resolved fluorescence microscopy, in addition to awards including the Wolf Prize in Chemistry, the Peter Debye Award in Physical Chemistry, the Earle K. Plyler Prize for Molecular Spectroscopy, and the Irving Langmuir Prize in Chemical Physics.

Professor Victor N. Nemykin

Professor Victor N. Nemykin
Department of Chemistry
University of Tennessee, Knoxville
Abstract

Creating new electron-deficient types of functional dyes that are potentially useful as electron acceptors in solar cells

We have developed synthetic protocols for the preparation of several classes of electron-deficient functional dyes that have a first reduction potential close to the traditional fullerenes. These include (i) functionalization of BODIPY core at meso-position; (ii) creation and functionalization of BOPHY platform; (iii) selective synthesis of 2-pyridone-BODIPYs; (iv) creation of electron-deficient “Manitoba Dipyrromethene” (MB-DIPY) chromophores and (v) discovery of hybrid β-isoindigo-aza-DIPY systems (Figure 1).

Victor N. Nemykin

Professor Victor Nemykin is currently a Head of the Department of Chemistry at the University of Tennessee - Knoxville. He was born and raised in Ukraine, where he received an undergraduate degree from Kyiv State University and a Ph.D. from the Institute of General and Inorganic Chemistry (1995). After JSPS (1998-2000) and Duquesne University postdoctoral positions, he was a faculty at the University of Minnesota - Duluth (2004-2016) and Professor and Head of the Department of Chemistry at the University of Manitoba (2016-2020). He co-authored more than 265 research papers, reviews, and book chapters.

Professor Philippe Buhlmann

Professor Philippe Buhlmann
Department of Chemistry
University of Minnesota

Electroanalytical Sensing with Polymeric Receptor-Doped Sensor Membranes

Selective electrodes for the detection of ions in liquids such as human body fluids or environmental waters are highly sensitive and selective analytical tools that offer a variety of advantages, such as simplicity of measurement, high analysis throughput, rapid detection, continuous on- line monitoring, and low cost of analysis. While such sensors are used in clinical laboratories for billions of measurements every year, applications in continuous health monitoring, the food industry, and environmental sciences still pose challenges. The Buhlmann group has contributed to the development of such sensors with new design principles and quantitative theory as well as the introduction of new materials to meet the needs of real life applications. This talk will address the long-term sensor stability of wearable and implantable sensors, challenges and opportunities of calibration-free measurements, miniaturization and low-cost design for point-of-care analysis, and—in view of long-term monitoring in the human body and the environment—robust design and resistance to chemical and biological fouling.

Philippe Buhlmann

Professor Philippe Buhlmann has been a member of the University of Minnesota Department of Chemistry since 2000. His group’s research is interested in the use of molecular recognition for chemical sensing. Their chemical sensor development focuses on new receptors that bind analytes of interest with high selectivity, novel strategies to obtain very low detection limits, and perfluoropolymers that permit long- term monitoring and eventually the implantation into the human body. Buhlmann’s research also pursues new ways to chemically modify metal and carbon nanotube tips, and use them in scanning tunneling microscopy for chemically selective imaging with molecular resolution.

Over the past two decades, his dedication to research and mentorship have earned the 3M/Alumni Professorship and the Distinguished University Teaching Professorship. Earlier this year, he received the American Chemical Society’s 2023 Minnesota Award “for being an international authority in the field of ion-selective electrodes and related research fields, for his outstanding work in volunteering for MN ACS, for being an outstanding research advisor, mentor, scholar and teacher AND having a positive impact on the lives of many graduate students in his own research group, in the Chemistry Department, and beyond.”

Professor Lynn Walker

Professor Lynn Walker
Department of Chemical Engineering and Materials Science
University of Minnesota
Flier

Engineering fluid-fluid interfaces through processing and multicomponent adsorption

Systems involving deformable interfaces between immiscible fluids offer a significant challenge for materials design and processing. Static interfacial/surface tension is often the only parameter considered in the design of systems with fluid-fluid interfaces. In foams, emulsions, blends, sprays, droplet-based microfluidic devices and many other applications, the dynamic nature of surface active species and deformation of interfaces requires a more detailed characterization of the interfacial transport, dynamic interfacial properties and interfacial structure. Macroscopic properties and the ability to tune and control phenomena requires an improved understanding of the time-dependent properties of the interfacial tension and interfacial mechanics. We have developed tools and approaches to quantify the impact of surface active species, particularly polymeric species, on interfacial behavior. Surfactant-nanoparticle complexes, polymer-surfactant aggregates and proteins (sequence specific polymers) show the potential of interfacial processing in controlling interfacial properties. The use of sequential adsorption, differences in transport timescales and variability in reversibility of different species allows interfaces to be engineered. This talk will provide the motivation to use microscale interfaces for efficient analysis of complex interfacial phenomena and how that relates to the material properties of interface-dominated materials

Professor Lynn Walker

Prof. Lynn Walker received her B.S. degree from the University of New Hampshire and a Ph.D. from the University of Delaware, both in chemical engineering. Prior to joining CEMS, she was at Carnegie Mellon University in Chemical Engineering and both Chemistry (by courtesy) and Materials Science & Engineering (by courtesy). She was an NSF International Postdoctoral Fellow at the Katholieke Universiteit in Leuven, Belgium before joining CMU in 1997. She has held visiting faculty positions at the Polymer IRC in Leeds, UK, Chemical Engineering at UCSB, and held the Piercy Visiting Professorship at the University of Minnesota. Her research focuses on quantifying the coupling between flow behavior and flow-induced microstructure in complex fluids. Currently her research focuses in two directions: quantifying the influence of flow on self-assembled nanostructures and controlling transport to complex fluid-fluid interfaces. She recently took the role of Perspectives Editor for AIChE Journal, served as Editor-in-Chief of Rheologica Acta and serves on the editorial boards of the Journal of Rheology, and Journal of Non-Newtonian Fluid Mechanics. She is a fellow of the American Institute of Chemical Engineers, the Society of Rheology, and the American Physical Society (DSOFT).