Chemistry Colloquium Program

"New NLO Materials: Design, Synthesis, and Crystal Growth"

Nonlinear optical (NLO) materials are critical in generating coherent light through frequency conversion, e.g., second harmonic generation (SHG). From the ultraviolet (UV) to the infrared (IR), NLO materials have expanded the range of the electromagnetic spectrum accessible by solid-state lasers. Wavelengths where NLO materials are still needed include the UV (~200 - 400nm) and deep UV (< 200nm). Coherent deep-ultraviolet (DUV) light has a variety of technologically important uses including photolithography, atto-second pulse generation, and in advanced instrument development. Design strategies will be discussed, as well as synthetic methodologies. In addition, the crystal growth, characterization, and structure-property relationships in new UV and DUV NLO materials discovered in our laboratory will be presented. Finally, our crystal growth capabilities and recent crystal growth of functional materials will be described.

"How social belonging in General Chemistry affects student performance and persistence, and what characteristics do students use in describing their belonging?"

Studies show that social belonging affects student learning and retention. In general chemistry - as well as introductory physics, introductory biology, and organic chemistry - we are studying both student’s sense of belonging and the less examined factor “uncertainty in social belonging” within a course. Our findings indicate that these affective variables influence student performance and persistence. To deepen our understanding of how social belonging influences students, we are examining their written responses for their reported levels of belonging in a course. Specifically, we are interested in determining the course features that students perceive as affecting their belonging. We hope this information will guide instructors in modifying their teaching practices to foster a greater belonging in their courses.

"Ligand design for earth-abundant transition metals to model active sites and promote cooperative catalysis"

Many processes of significant importance to the ongoing development of the clean energy economy depend on transition metals, including as catalysts for fuel production and for charge storage in batteries.  Optimizing these processes, especially so that they can be carried out with earth-abundant transition metals, requires careful control of the metal’s environment.  This can be accomplished through ligand design, including the design of ligands that incorporate cooperative properties.  Much of our work broadly focuses on developing ligands, reagents, and transition metal complexes which have potential applications in, and/or provide fundamental insight into, these types of processes.  This includes (1) first-row transition metal complexes of pyrazine(diimine) ligands which catalyze hydrogen evolution through ligand-centered cooperative process; (2) bioinspired chelators with tunable selective binding that control the redox properties and spin states of coordinated transition metals through steric effects; and (3) newly developed pathways to install terminal methylidyne ligands as models for processes on the surface of heterogeneous transition metal catalysts.

About the Speaker: Sid Creutz is an Associate Professor at Mississippi State University. His group’s research focuses on synthetic inorganic chemistry, including organometallic chemistry, bioinorganic chemistry, and semiconductor nanomaterials synthesis.  Research is funded by the U.S. National Science Foundation, National Institutes of Health, and the American Chemical Society. 

"Saloplastics: Processing Blends of Charged Polymers with Salt"

Charged polymers, or polyelectrolytes, are widely used in technology. Mixtures of oppositely-charged polymers spontaneously form complexes, which can be solid-like or liquid-like. In either case, salt solutions can be used to break the electrostatic crosslinks between polymers and therefore soften them, much like heat softens thermoplastics. These polyelectrolyte complexes, PECs, offer a wide range of applications and morphologies. This talk will focus both on the mechanisms controlling the mechanical properties of PECs and on some of their new useful applications.

"Applying to and Succeeding in Tenure-Track Research Faculty Positions at Primary Undergraduate Institutions"

Dr. McCauley is an Associate Professor in the Department of Chemistry & Biochemistry at California State University Dominguez Hills (CSUDH). She is the Program Director for the NIH Undergraduate Research Training Initiative for Student Enhancement (U-RISE), the Beckman Research Scholars, and the Elements of Equity Student Research Programs. Additionally, she has served as the Chair of the Department’s Tenure Track hiring committee since 2022. This talk will be catered to students and postdocs who are interested in pursuing careers as faculty members at Primary Undergraduate Institution (PUI), and will cover: 1) How to put together a successful application package with strong undergraduate research plans and teaching statements; 2) how to successfully navigate the interview process; and 3) how to build a strong sustainable undergraduate research program once hired so that you can successfully proceed through the tenure process

"Molecular Imaging in Clinical & Translational Research"

Positron emission tomography (PET) has emerged as a critical biomedical imaging modality for in vivo visualization and quantification of various pathophysiological processes in normal human development and disease. PET is routinely used for the clinical diagnosis in oncology, cardiology and in neurodegenerative disease as well as clinical and translational research applications. Professor Snyder will introduce the basics of PET imaging and the process of systematically developing and advancing novel diagnostics from benchtop to bedside. He will describe the role of PET in novel therapeutic development, the investigation of disease mechanisms, and the identification of unique biomarkers. Specific examples will include the diagnosis and staging of cardiomyopathies and brain tumors, detection of therapeutic targets in solid tumors, and investigation of various pathological processes during disease progression in Alzheimer’s Disease.

"Nanoscale Iron Oxide Surfaces: From Low Temperature Graphene to Supersensitive Magnets"

Nanoparticles present an enormous amount of surface to the world: a small speck of nanoparticulate rust, for example, can possess the surface area of a basketball court.  We are now able to design this interface with a great deal of molecular precision opening the door for new applications.  This talk will illustrate this in three case studies.  In the first, nanoparticle-polymer interfaces are used as a template for biomolecular association leading to soft assembly driven by biomolecular crystallization.  When the nanoparticle-polymer interface is less densely packed, these complexes rapidly nucleate crystallization of Albumin and Lysozyme.  The resulting single crystals are examples of novel biomolecule-nanoparticle composites with unique properties and applications.  The second case study illustrates how the hard interface between adjacent magnetic nanoparticles in supercrystals can lead to collective magnetic properties distinct from isolated particles or bulk materials.  When iron oxide nanoparticles share crystalline interfaces, as they do in these porous and aligned assemblies, then their collective properties are defined both by dipolar interactions as well as exchange interactions.  The latter feature is particularly powerful as it results in highly sensitive soft magnets that can be fully magnetized at extremely low external magnetic fields.  The last case study illustrates how it is possible to leverage the reactive surfaces of iron oxide at low temperatures in a liquid phase to generate graphitic carbons through thermal decomposition of fatty acid feedstocks.  Normally such conversions require elevated temperatures and solid-state processing.  This chemical approach opens up a new avenue for exploring more sustainable methods for generating conductive carbon materials.

"A conceptual approach to understanding complexity using the tools of theory and simulation"

I will discuss how simple concepts in theoretical physical chemistry can be used to understand complex phenomena in the condensed phase.  I will emphasize Coulombic systems and discuss phenomena ranging from fundamentals of solvation to collective effects such as (anomalous) screening.  I will discuss the role of the coupling between short-range and long-range interactions to construct models of reduced complexity to connect with experimental observations of complex phenomena in liquids.

"Microporous Membranes and Recyclable Polymers Enabled by Overlooked Chemistry for a Sustainable Future"

Innovative polymer chemistry plays an important role in achieving a sustainable future. I will present two types of polymers synthesized from commercially available chemicals for energy-efficient chemical separations and as recyclable high-performance thermosets. The first type is extremely glassy ladder-shaped polymers from norbornadiene and aryl bromides via an efficient annulation polymerization. These polymers have abundant microporosity, and can be cast into mechanically robust membranes with a remarkable size-sieving effect after an intriguing aging process. These membranes give an unprecedented combination of ultrahigh selectivity and permeability for the separation of industrially important gases with low energy input. The second type of polymers is recyclable thermosets based on polydicyclopentadiene with excellent mechanical strength and toughness. Their recyclability is enabled by an overlooked olefin metathesis reactivity of enol ethers. A small fraction of cyclic enol ether as an additive allowed us to prepare thermosets and composites in an energy efficient frontal process. These materials have convenient processibility, tunable thermomechanical properties, can be chemically deconstructed on-demand and recycled multiple times while maintaining the processability and material properties. I will discuss the enabling chemistries for the development of these polymers, optimization of their material properties and performance, and paths toward real-world applications.