UCLA

Boehringer-Ingelheim Seminar: Selective Catalytic Functionalization of C-H Bonds
2020-10-22 16:00 (America/Los_Angeles)
Abstract:The selective introduction of functional groups at the positions of typically unreactive C-H bonds has been a longstanding challenge in catalysis. To this end, our group has developed practical methods for the catalytic functionalization of C-H bonds with main group reagents.(1-4) These studies have led us to a general strategy of installing a single transient functional group to form a range of products from one C-H bond functionalization reaction. This research has led us to seek next-generation catalysts for the functionalization of C-H in complex molecules, new classes of reactions for functionalization of these bonds, and new strategies, such as the construction of artificial metallenzymes to control the site at which such reactions occur.
This lecture will present recent directions of research in our group toward discovering selective reactions of both small and complex molecules with large and small catalysts. The design and selection, as well as the intimate mechanism, of catalysts and catalytic reactions for selective functionalization processeswill be presented.

Chem 268: Guillaume Chanfreau and Cathy Clarke
2020-10-23 15:30

Chem 228: Prof. Christine Isborn
2020-10-26 16:00
“Simulating linear and nonlinear optical spectra for chromophores in the condensed phase”

Teaching opportunities after grad school in primarily undergraduate institutions
2020-10-27 12:00
Panelist:
Prof. Jennifer Casey
Dept. of Chemistry and Biochemistry
University of California, Los Angeles
&
Prof. Jay Foley
Dept. of Chemistry
William Paterson University
&
Prof. Jacob Olshansky
Dept. of Chemistry
Amherst College

Midstream Presentation: Evan Maltz
2020-10-27 16:00
Evan Maltz
Wollman Group
“Phenotypic Consequences of Gene Expression Variability”

Chem 278: Prof. Yuzhang Li
2020-10-28 16:30
“Imagining, Building, and Understanding the Next Generation Battery”
Abstract: Electrochemical energy conversion and storage is critical for vehicle electrification and storing clean energy from intermittent sources (i.e. wind, solar) on the grid. Towards these goals, my group pursues the broad spectrum of stages necessary for technological innovation: (1) developing new tools to discover fundamental understandings, (2) designing and synthesizing unique materials to address intrinsic failure modes, and (3) patenting the technology for real world applications. In this talk, I will first discuss a graphene cage design strategy to stabilize the silicon anode for high-energy Li-ion battery chemistries. Next, I will introduce the powerful cryogenic-electron microscopy technique that we have pioneered for atomic-resolution studies on sensitive and reactive battery materials. Using this technique, new discoveries at the nanoscale are correlated with macroscopic battery performance, further expanding our understanding of battery failure mechanisms and providing insight for future materials design.

Some Simple Concepts and Their Consequences in Covalent Mechanochemistry
2020-10-29 16:00
Abstract:The potential to use mechanochemistry, either in isolated polymers or in polymeric materials, to trigger a programmed, desirable covalent molecular response was first revealed only a decade or so ago. Since that time, covalent polymer mechanochemistry has undergone a renaissance in which it has been extensively explored by a number of research groups and for a variety of purposes including (but not limited to) biasing and probing reaction pathways, trapping transition states and intermediates, catalysis, release of small molecules and protons, stress reporting, stress strengthening, and soft devices. Increasingly creative mechanophore designs and new properties continue to emerge at an ever-accelerating pace.
The precision with which mechanophores can be predictively designed has increased as quantitative experimental and computational studies have provided insights into structure-activity relationships. Additional benefits will be realized as these quantitative relationships are mapped onto existing, intuitive physical organic frameworks. This talk will present quantitative studies of mechanochemical reactions and their mechanisms, highlighting opportunities for classical physical organic principles and the new chemistry empowered by mechanochemistry to enrich each other.

Chem 268: Margot Quinlan and Todd Yeates
2020-10-30 15:30

Midstream Presentation: Matthew Paul Agdanowski and Janine Fu
2020-11-03 16:00
Matthew Paul Agdanowski
Yeates Group
“The Development of an Imaging Scaffold for RNA Structural Analysis via Cryo-EM”
and
Janine Fu
Loo Group
“Targeting acyl-lysine modifications in the Rhodopseudomonas palustris proteome via diagnostic ions”

Chem 278: Dr. Jiao Deng
2020-11-04 16:30
“Ambient Electrochemical Functionalization of Methane with d0 early transition metal-oxo species”
Abstract: The abundant yet widely distributed methane (CH4) resources demands an efficient conversion of CH4 into liquid chemicals at ambient conditions with minimal infrastructure support. In the existing approaches of metal-catalyzed reactions and catalysis based on free-radical chain mechanism, the reactivities of the former metal species seem insufficient to achieve ambient activation of CH4 and the latter radical species are uneasy to be sustainably replenished. This talk will show that a controlled electrochemical generation of oxygen radicals on the ligands binding to d0 early transition metal centers is capable to address the above-mentioned challenge, given the electrochemical redox process provides a sustained method of replenishing radical species at ambient conditions without sacrificing their high reactivities. This proposed mechanism represents a new scalable approach that helps mitigate the flaring or direct emission of natural gas at remote locations.

Combining Theory and Experiment to Develop Selective Three-Component Fe-Catalyzed Radical Cascade/Cross-Couplings
2020-11-05 16:00
Abstract: Despite advances in high-throughput screening methods leading to a surge in the discovery of catalytic reactions, our knowledge of the molecular-level interactions in the rate- and selectivity-determining steps of catalytic reactions, especially those involving highly unstable and reactive open-shell intermediates, is rudimentary. These knowledge gaps prevent control, suppression or enhancement, of competing reaction channels that can drive development of unprecedented catalytic reactions. In this talk, I will focus on our use of high-level quantum mechanical calculations, rigorously calibrated against experimental data, to interrogate the mechanisms and to guide the development of new catalysts and reagents for currently sluggish or unselective reactions. In particular, I will focus on our use of combined experimental and computational tools to understand and develop new (asymmetric) three-component iron-catalyzed radical cascade/cross-coupling reactions.

Chem 268: Rob Clubb and Carla Koehler
2020-11-06 15:30

Chem 228: Prof. Brenda Rubenstein
2020-11-09 16:00
“Computing with Molecules: Storage and Classical Computation Using Small Molecules and Their Reaction Networks”

Midstream Presentation: Kyle Meador and Natalie Schibrowsky
2020-11-10 16:00
Kyle Meador
Yeates Group
“Design and Assembly of 3D Protein Crystals”
and
Natalie Schibrowsky
Rodriguez Group
“Biochemical and structural analysis of in vivo Cry11Bs crystalline inclusions”

Chem 218: Prof. Vanessa Wood
2020-11-12 12:00
“Structure and Surfaces at the Nanoscale”
Abstract: Liquid-phase and wet-processing techniques offer tremendous opportunities for low-cost manufacturing and enable the concept of large-scale nanotechnology. Today, these approaches have facilitated the massive upscaling of lithium ion battery technology and promise to play a future role in a wide variety of electronic, photonic, and electrochemical systems. Materials and devices made from these approaches often exhibit hierarchical structures and have complex interfaces that are key to their performance. In this talk, I will describe the importance of understanding structure-performance relationships to achieve the full potential of solution processed systems.
To characterize structure and structural dynamics in these complex, multiscale materials, we leverage a wide variety of techniques including electron microscopies, x-ray imaging, diffraction, and scattering, neutron scattering and imaging, and muon spectroscopy. Combining information from characterization with simulation and experiment, we use our findings to understand the origins of performance limitations and develop design guidelines to systematically improve material and devices.
My talk will present several examples, including the role of nanocrystal surfaces in determining their emission linewidths, carrier cooling, and charge transport, and the role of nanoscale structure and surface chemistry on electrolyte infilling in lithium ion batteries and lithium transport. I will address the experimental and computational challenges associated with studying these systems and emphasize ways machine learning techniques and systematic leveraging of size control the nanoscale can be used to overcome these challenges.

Development of New Chemical Platforms for Polymer Synthesis
2020-11-12 16:00
Abstract: Synthetic polymers have permeated nearly every facet of modern life. From the ubiquity of polyolefins to recent advancements in 3-D printing, organic materials continue to shape the world around us. While tremendous accomplishments have been made with relatively few polymer families, the future requires the development of materials with increased control over structure to produce systems that can respond to programmed inputs, as well as the exploration of entirely new polymer compositions. Our group takes a chemistry-focused approach to address these challenges through the strategic application of organic methodologies to design new monomer families and reagents for precision polymer synthesis. This presentation will specifically highlight (1) the utility of enyne chemistry to impart degradability and expedite functionalization of metathesis-derived materials and (2) the development of a new class of living polymerization that is enabled by the unusual reactivity profiles of twisted amide molecules.

Chem 268: Juli Feigon
2020-11-13 15:30

Chem 228: Alex Wiltschko, Ph.D.
2020-11-16 16:00
“Machine learning for scent”

NSF Center for Integrated Catalysis Webinar Series
2020-11-17 13:00
The NSF Center for Integrated Catalysis is delighted to announce that it will be hosting a monthly webinar series. The second day of this series will be held on Tuesday, November 17th at 1:00 PM. We are pleased to invite all students, postdocs, faculty, and staff.

Midstream Presentation: Carter Lantz
2020-11-17 16:00
Carter Lantz
Loo Group
“Mass Spectrometry Analysis of Amyloid Proteins and their Interaction with the Aggregation Inhibiting Compound CLR01”

Chem 278: Prof. Caroline Saouma
2020-11-18 16:30
“Thermodynamic and Mechanistic Studies of C02Reduction Catalysts”
Abstract: 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.

Writing the rules for targeting dynamic proteins
2020-11-19 16:00
Abstract: Transcriptional coactivators and their partner transcription factors have been labeled as intrinsically disordered, fuzzy, and undruggable. We propose that the identification of conserved mechanisms of engagement between coactivators and their cognate activators should provide general principles for small-molecule modulator discovery. Towards that end, biophysical characterization of the structurally divergent coactivator Med25 reveals that it forms short-lived and dynamic complexes with three different transcriptional activators and that conformational shifts are mediated by a flexible substructure of two dynamical helices and flanking loops. Analogous substructures are found across eukaryotic coactivators. Further, targeting one of the flexible structures with a small molecule modulates Med25-activator complexes. Thus, the two conclusions of the work are actionable for the discovery of small-molecule modulators of this functionally important protein class.

Chem 268: Steve Clarke
2020-11-20 15:30

Chem 228: Prof. Brandi Cossairt
2020-11-23 16:00
“Interfacial Chemistry of Colloidal Nanocrystals to Direct Energy Conversion”

Interfacial Chemistry of Colloidal Nanocrystals to Direct Energy Conversion: Prof. Brandi Cossairt, University of Washington
2020-11-23 16:00
Interfacial Chemistry of Colloidal Nanocrystals to Direct Energy Conversion
We are interested in developing colloidal nanocrystals for wide-ranging applications in energy interconversion. Our approach leverages the extraordinary properties of nanoscale systems and applies design principles of molecular inorganic chemistry. This talk will focus on two key research themes. First, we will explore how interfacial chemistry can be used to control the photophysics and emissive properties of colloidal semiconductor nanocrystals. Second, we will explore interfacial chemistry concepts to control the inner-sphere reactivity of colloidal electrocatalysts for multi-proton, multi-electron transformations. Ligand etching, ligand exchange, and covalent functionalization will be presented as complementary methods to alter electrocatalytic interfaces by tuning the activity, selectivity, and bulk interfacial properties. Ultimately, we are viewing nanocrystal interfaces as platforms for coordination chemistry that will direct function.

Midstream Presentation: Maria Flores and Logan Scott Richards
2020-11-24 16:00
Maria Flores
Rodriguez Group
“Investigating the atomic structures of prion-like assemblies formed by CPEB3”
and
Logan Scott Richards
Rodriguez Group
“Structural Characterization of LECT2 Systemic Amyloidosis”

Chem 228: Prof. Amber Krummel
2020-11-30 16:00
“Exploiting Molecular Vibrations to Visualize Chemical Structures & Dynamics in Advanced Materials”

Midstream Presentation: Troy Lucas Lowe
2020-12-01 16:00
Troy Lucas Lowe
S. Clarke Group
“Responses of a Protein Arginine Methyltransferase (PRMT7) to Intracellular Stress”

Chem 278: Dr. Evan Doud
2020-12-02 16:30
“Beyond Traditional Superatom Ligands and Cores”
Abstract: As technological development continues to advance at a rapid pace, there is an increasing need for next-generation materials. There are several fundamental challenges associated with developing these novel materials, including understanding the nature of the electronic contacts and tuning the specific properties of a material. In the context of novel ligands and core compositions of superatoms, this talk will first describe how Near Edge X-ray Absorption Fine Structure (NEXAFS) and X-ray Photoelectron Spectroscopy (XPS) coupled with Density Functional Theory (DFT) calculations were used to determine the geometry and structure of N-heterocyclic carbenes (NHCs) on a Au(111) surface. Followed by a demonstration of how a novel in situ reduction technique was used to probe the conductance of NHCs on the single molecule level using the Scanning Tunneling Microscopy – Break Junction (STM-BJ) technique. Finally, the synthesis of nickel phosphinidene superatoms from the uncommon organocyclophosphine precursor will be discussed

Chem 218: First Principles Many-Body Theory and Quantum Dynamics for Materials Prediction - Prof. Yuan Ping, UCSC
2020-12-03 12:00
First Principles Many-Body Theory and Quantum Dynamics for Materials Prediction
Materials prediction is the ultimate solution for ending blind experimental search within an expansive material parameter space. First-principles theory entirely based on quantum mechanics without prior input parameters is the perfect tool for new material design. In order to predict exotic quantum materials and out-of-equilibrium processes, many-body physics and quantum kinetic theory are needed to bridge with first-principles methods.
In this talk, I will discuss the past development on theory and numerical codes of solving the Bethe-Salpeter equation without explicit empty states, for accurate prediction of optical excitation and exciton recombination. I will show the recent developments on radiative and phonon-assisted nonradiative exciton recombination in two-dimensional materials and spin defects. Next, I will show our recent method development on real-time quantum dynamics with coupled spins, electrons, photons and phonons based on first-principles density-matrix approach. This method will offer new and unbiased insights for spin relaxation and decoherence in general systems, and determine design rules for new quantum materials with ideal physical properties for spintronics and quantum information science.
