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Thursday, May 27 • 9:00am - 10:30am
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Parker Morris Designer Catalysts: The Role of Sterics on Nickel Catalyzed Allylbenzene Isomerization
Synthetic chemistry is vital to manufacturing daily household products such as perfumes, food additives, and synthetic materials. The chemical industry manufactures chemical products on the million tons scale yearly and developing energy efficient ways to create these materials is an important area of study for organic and inorganic chemists. One approach to increasing reaction efficiency is through the use of a metal catalyst. Unfortunately, some of the most successful metal catalysts are derived from precious metals such as platinum, palladium, iridium, or ruthenium. Nickel is a cheap, earth abundant alternative to the precious metal counterparts.  This project saw the synthesis of four nickel-based n-heterocyclic carbene complexes to be used in catalytic isomerization reactions. The primary goal of the study was to determine the role of ligand sterics on product distribution and kinetics in the isomerization of allylbenzene via nickel catalysis. Contrary to hypotheses, it was determined that with larger steric incumbrance, the rate of reaction increased as did overall yield. Additionally, synthetic routes to reach these complexes were established starting from cheap and available starting materials.  

Lillian Payne Inducing Photo-accessible Metal States in Zirconium Metal Organic Frameworks 
Photocatalysis, the acceleration of a photoreaction in the presence of a catalyst, is utilized in many famous industrial processes such as water splitting, water purification, and CO2 conversion. Metal organic frameworks (MOFs) are desirable for photocatalytic applications. To effectively preform photocatalytic transformations, long exciton lifetimes are needed. Ti(IV) MOFs have provided these long exciton lifetimes through ligand to metal charge transfer and metal-localized proton coupled electron transfer (PCET), but similarly structured Zr(IV) MOFs show less stable ligand to ligand excitations. This difference can be attributed to the lack of photoaccessible metal states at the conduction band edge in Zr(IV) MOFs. We show here that destabilizing the linker orbitals through removal of aromaticity gives access to metal states and allows stable excitations through a Zr(IV)/Zr(III) redox couple upon PCET.  

Haley Rice Exploring Oxaliplatin Derivatives Through Modification of the 3,4 Position 
Platinum anti-cancer compounds have been in clinical use for over 40 years and are used in around 20% of cancer regimes today. Despite their long use, the widespread binding activity for the three FDA approved platinum drugs, cisplatin, oxaliplatin and carboplatin, has not been well studied. The mechanism of action for cisplatin is through DNA damage response, however, it was recently discovered that oxaliplatin’s mechanism of action is through ribosome biogenesis stress, also referred to as nucleolar stress. Previous research in the DeRose lab has established structural characteristics necessary for platinum compounds to cause nucleolar stress, including hydrophobicity, steric bulk, and directionality. To determine what biomolecules are interacting with these platinum compounds, we aim to create an azide incorporated oxaliplatin mimic which can be used to pull down biomolecules. Here we investigate the 3,4 position of the cyclohexane ring of oxaliplatin to determine the window of tolerance in which an azide could be incorporated on the scaffold. We synthesize oxaliplatin derivatives with varying groups in the axial and equatorial position and determine whether these derivatives cause nucleolar stress using an nucleophosmin (NPM1) relocalization assay in non small cell lung cancer. Better understanding the targets of oxaliplatin may illuminate the specific biomolecules binding to platinum which can be used to better design new platinum compounds for use in cancer treatments. 

Stacey Andreeva Structural changes in organic-inorganic hybrid materials dictated by bond dynamics 
Dynamic chemical bonding is responsible for the basic mechanism of crystallization for many material systems because erroneous bond formation can be corrected through facile reversal until the material settles into the most favorable crystalline phase. A particularly important class of crystalline materials that emerge from this dynamic process are metal-organic frameworks (MOFs). For the past two decades, MOFs have been viewed as rigid structures, but we propose that even after formation, MOFs contain metal-ligand bonds that remain dynamic such that the crystalline structure contains mixtures of partially tight and loose arrangements. We hypothesize that metal-linker bonds are especially dynamic, and with variable-temperature diffuse reflectance infrared Fourier transform spectroscopy (VT-DRIFTS) aided by ab initio plane wave density functional theory, we demonstrate that similar evidence for melting behavior in zeolitic imidazolate frameworks (ZIFs) – reversible metal-linker bonding driven by specific vibrational modes – can be observed for other classes of MOFs by monitoring the redshifts of stretches coupled to metal-linker modes. We present general evidence that challenges the common perception of MOF metal-linker bonds being static. Insight into their labile nature would provide a predictive model of their growth mechanism and inspire important applications such as the use of MOF for self-healing membranes. 

Thursday May 27, 2021 9:00am - 10:30am PDT