(1:00-1:15)
[50 - 180-330]: Engineering CO$_2$ Capture: Functionalizing COFs with Guanidine-Based Sorbents
Jacob Bellamah†★, Daniel BercoviciDepartment of Chemistry and Biochemistry, †Frost Support, ★Speaker
Rising atmospheric CO$_2$ levels continue to drive the need for efficient capture technologies, motivating the development of solid sorbent systems with improved performance and scalability. Guanidine-based materials such as pyridine bis-iminoguanidine (PBG) offer selective CO$_2$ binding and low-temperature regeneration, but their solid-state application is limited by poor gas–solid contact. This work focuses on the synthetic development of a PBG-functionalized Covalent Organic Framework (COF), with an emphasis on designing and validating functionalized pathways. Initial efforts have been centered on constructing a molecular COF-mimic system to identify key synthetic challenges, optimize synthetic strategies, and confirm functional group compatibility. Insights from this model system will guide the subsequent synthesis of the imine-linked covalent organic framework (COF) and its post-synthetic functionalization with PBG-based moieties. Throughout this process, particular attention was given to reaction feasibility, framework integrity, and retention of functional groups during incorporation. Materials are characterized using NMR to assess successful functionalization and structural preservation. This work highlights the synthetic approach required to integrate CO$_2$-active functional groups into COFs and evaluates the feasibility of translating molecular sorbents into structured materials for direct air capture applications. |
(1:15-1:30)
[51 - 180-330]: Ester-Aryl Ylidenenorbornadienes: Synthesis and Reactivity of Aryl Propiolate Dieneophiles
Michael Cunningham†★, Daniel BercoviciDepartment of Chemistry and Biochemistry, †Frost Support, ★Speaker
Ester-Aryl Ylidenenorbornadienes (EAr-YNDs) are a class of stable bridged bicyclic molecules that are synthesized via a [4+2] cycloaddition between a fulvene diene and aryl propiolate dieneophile. However, a thiol nucleophile can react with the YND to produce a YND-thiol adduct that spontaneously performs a retro-[4+2] fragmentation. The rate of this fragmentation reaction and the regioselectivity of the thiol addition are highly dependent on the electronics of the aryl substituent. Developing these electron-withdrawing aryl propiolate derivatives will improve the understanding of how electronics affect the YND system. Substituent selection was determined by the Hammet parameter (?p), which represents relative electron deficiency in aryl substituents. A substrate scope of nine different aryl propiolates has been synthesized. Within the scope, the most electron-withdrawing aryl propiolate is the trifluoromethanesulfonyl with a ?p of 0.96, and the phenyl group is electronically neutral with a ?p of 0. These aryl propiolates will be used to make the following EAr-YNDs and will be further investigated. |
(1:30-1:45)
[52 - 180-330]: Probing the Lewis Acidity of Boronate Ester COF Colloids Surfaces with Fluorescent Lewis Adducts
Sofia Valencia†★, Jackson Arroyo, Leslie HamachiDepartment of Chemistry and Biochemistry, †Frost Support, ★Speaker
Covalent organic frameworks (COFs) are crystalline, porous polymers with potential applications in chemically active separations, gas capture, and catalysis. Despite advances in colloidal synthesis, the relationship between COF particle size, surface Lewis acidity, and catalytic activity is poorly understood. Recent synthetic advancements have provided access to colloidal single-crystalline COFs, presenting the opportunity to study their size-dependent performance and properties. In this study, the interaction between the Lewis acidic external borons on COF-5 and a Lewis basic fluorescent probe are used to examine the size-dependent COF-5 surface acidity, which we will use to investigate the relationship between crystallite size and catalytic ability. |
(1:45-2:00)
[53 - 180-330]: Improved Kinetic Analysis of Diaryl Ylidenenorbornadiene Fragmentation Using ¹F NMR
Jonathan Moore★, Daniel BercoviciDepartment of Chemistry and Biochemistry, ★Speaker
The synthesis of a model symmetric diaryl-ylidenenorbornadiene (YND) system has previously been reported via reaction of 6,6-diaryl-substituted fulvenes with dimethyl acetylenedicarboxylate. These YNDs subsequently undergo Michael addition with propanethiol (PT), affording four distinct diastereomers that fragment spontaneously. Variation of electron-donating and electron-withdrawing substituents (ranging from dimethylamino to nitro groups) at the aryl positions resulted in fragmentation rates spanning an order of magnitude, with half-lives ranging from 5 to 60 minutes for the fastest-fragmenting diastereomer (d2). However, interpretation of ¹H NMR spectra proved challenging due to partial diastereomeric impurities and significant peak overlap arising from the structural complexity of the bicyclic system. To address this limitation, fluorinated 6,6-diaryl-substituted fulvenes were investigated. Incorporation of fluorine enabled the use of ¹F NMR spectroscopy, providing a simplified spectral profile with significantly reduced peak overlap for the symmetric YND Michael adducts. This approach offers a more reliable method for monitoring fragmentation kinetics and may serve as a valuable alternative to conventional ¹H NMR analysis in complex systems.
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(2:00-2:15)
[54 - 180-330]: The Characterization of Inverse Opal Metal Oxides
Maelyn Peters1★, Elijah Hannaford2†★, Justin Hancock2, Leslie Hamachi21 Materials Engineering, 2 Department of Chemistry and Biochemistry, †Frost Support, ★Speaker
This project is the synthesis and characterization of high refractive index metal oxide structural color pigments. In these materials, color comes from the interaction of light on the pigment’s nanostructure, rather than differences in chemical composition from traditional pigments. For inverse opal, our chosen nanostructure, pore size dictates the perceived color of the material. Other researchers have successfully created the inverse opal nanostructure with a limited number of high refractive index metal oxides; but there is room for expansion on the metal oxides capable of forming the inverse opal structure. Inverse-opal nanostructure is created using a polymer template that takes the form of an opal lattice, then integrating a precursor metal oxide into the polymer template, proceeding to pyrolyze the template in a box furnace, leaving behind the metal oxide in the form of inverse-opal. To ensure we have properly made the inverse opal microstructure, we use the characterization methods of scanning electron microscopy, X-ray diffraction, and CIELAB color meter. Our data from these techniques shows the success of the formation of the inverse opal microstructure. |
(2:15-2:30)
[55 - 180-330]: Targeting Conceptions of Derivative: Introducing Derivatives in Calculus With Inquiry
Hannah Freund1†★, Chris Liu2†★, Morgan Raak1†★, Saba Gerami1†1 Department of Mathematics, 2 Department of Statistics, †Frost Support, ★Speaker
In this study, we leverage the Conceptions of Derivative (CoD) framework (Gerami et al., 2025) to analyze eight U.S. college calculus instructors’ instructional tasks for introducing derivatives. During four task-oriented interviews, each instructor proposed up to eight tasks for introducing derivatives with inquiry in their calculus I courses. Based on Zandieh's (2000) process-object model, the CoD framework was used to reveal derivative conceptions that instructors were targeting in their tasks. We identified four components of derivative conceptions targeted in the tasks: contextual framing, epistemological approaches (limit-based, infinitesimal/differential-based, and instrumental/rule-based), mathematical representations, and process-object layers. While pure contextual frames and limit-based approaches dominated early instruction of derivatives for these instructors, some targeted physics and biology contexts as well as infinitesimal/differential-based and rule-based epistemologies. We discuss implications for research on calculus teaching. |
(2:30-2:45)
[56 - 180-330]: Trisections of $4$-Manifolds via Covering Spaces
Matthew Stark†★, Tri Tran†, Terrin Warren†Department of Mathematics, †Frost Support, ★Speaker
Visualizing manifolds can be quite challenging in higher dimensions. In dimensions $3$ and $4$, we can break a manifold into simpler pieces and encode its structure using $2$-dimensional Heegaard diagrams and trisection diagrams, respectively. We examine the relationship between the spin operation and covering spaces. Specifically, we begin with genus-$1$ Heegaard diagrams of lens spaces and classify all of their covering spaces. This result is then extended to a family of $4$-manifolds called spun lens spaces. We then generalize further to get a description of a finite-sheeted covering space of any spun $4$-manifold $\mathcal{S}(X)$, which is obtained from ''spinning'' a covering space of a $3$-manifold $X$. |
(2:45-3:00)
[57 - 180-330]: Toward a robust and simple guideline for checking the Central Limit Theorem
Visruth Srimath Kandali†★, Beth ChanceDepartment of Statistics, †Frost Support, ★Speaker
In statistical practice, many introductory statistical procedures require the sampling distribution of means to be approximately normal. Most students learn a simplified check of this condition as “n ? 30”, which often becomes a black-and-white mantra replacing visual inspection of the data. A slightly more detailed version might be “n ? 30 as long as the population distribution is not too skewed.” Our research seeks to clarify a guideline that incorporates measures of skewness along with sample size. Extensions include specification of different error rates and corrections for sample skewness. We used simulation to explore the consequences of skewed populations with different sample sizes. We hope to provide students and practitioners with a more refined yet still viable guideline that encourages consideration of skewness. |