Physical Sciences and Mathematics Commons^™

Contra-Thermodynamic Halolactonization Of Lactam-Tethered 5-Aryl-4(E)-Pentenoic Acids For The Flexible And Stereocontrolled Synthesis Of Fused Lactam-Halolactones, Timothy K. Beng, Claire Borg, Morgan J. Rodriguez

All Faculty Scholarship for the College of the Sciences

Halolactonization of alkenoic acids enables the construction of oxygen-heterocycles via intramolecular halonium-induced nucleophilic addition. Although the literature is currently inundated with halolactonizations of 5-aryl-4(E)-pentenoic acids that predictably afford the 6-endo cyclization adducts, methods that reliably alter the innate regioselectivity bias to instead deliver the thermodynamically less favored 5-exo cyclization products are relatively rare. Here, we attempt to bridge this gap and have found mild conditions for contra-thermodynamic halolactonization of lactam-tethered 5-aryl-4(E)-pentenoic acids that lead to the formation of trans-fused lactam-γ-lactones. The natural proclivity for these 5-aryl-4(E)-pentenoic acids to undergo 6-endo cyclization is overridden and 5-exo-trig cyclization predominates. The success of …

Assessment Of The Toxicity Of Legacy And Next-Generation Perfluoroalkyl Substances (Pfas) In Early-Life Stages Of Freshwater And Marine Fish, Kiflom Gebreab

FIU Electronic Theses and Dissertations

Per- and polyfluoroalkyl substances (PFASs) are a group of synthetic surfactants that have utilized for several decades in a wide range of industrial and manufacturing applications. Owing to their high chemical stability, PFAS are widespread and persistent in the environment, and have been shown to be bioaccumulative in diverse organisms including plants, wildlife, and humans. Exposure to PFASs has been linked to a range of documented toxic and/or adverse effects in relation to human and animal health. The potential environmental health and ecotoxicity of next-generation PFAS remain unclear. In the present study, toxicity, and bioconcentration potential, of several perfluoroether carboxylic …

Stereocontrolled Access To Δ-Lactone-Fused-Γ-Lactams Bearing Angular Benzylic Quaternary Stereocenters, Timothy K. Beng, Morgan J. Rodriguez, Claire Borg

All Faculty Scholarship for the College of the Sciences

C-fused γ-lactam-lactones are resident in several bioactive molecules, including anticancer agents such as omuralide. In this embodiment, we report mild conditions for the catalytic halolactonization of lactam-tethered 5-aryl-4(E)-pentenoic acids. The use of dichloromethane as the solvent and Ph₃PS as the catalyst led to predominant 6-endo-trig cyclization and furnished the trans-fused-γ-lactam-δ-lactones. The transformation is modular, regioselective, chemoselective, and diastereoselective. The γ-lactam-δ-lactones bear angular quaternary benzylic stereocenters, which is noteworthy since the presence of a quaternary carbon in bioactive small molecules often promotes an element of conformational restriction that imparts potency, selectivity, and metabolic stability. The …

Prediction And Confirmation Of A Switch-Like Region Within The N-Terminal Domain Of Hsirt1, Angelina T. Huynh, Thi-Tina N. Nguyen, Carina A. Villegas, Saira Montemorso, Benjamin Strauss, Richard A. Pearson, Jason G. Graham, Jonathan Oribello, Rohit Suresh, Brooke Lustig, Ningkun Wang

Faculty Research, Scholarly, and Creative Activity

Many proteins display conformational changes resulting from allosteric regulation. Often only a few residues are crucial in conveying these structural and functional allosteric changes. These regions that undergo a significant change in structure upon receiving an input signal, such as molecular recognition, are defined as switch- like regions. Identifying these key residues within switch-like regions can help elucidate the mechanism of allosteric regulation and provide guidance for synthetic regulation. In this study, we combine a novel computational workflow with biochemical methods to identify a switch-like region in the N-terminal domain of human SIRT1 (hSIRT1), a lysine deacetylase that plays important …

Stem Club, Camden Jones, Erica Gesner, Amber Gadeken

Honors Expanded Learning Clubs

The goal of this club is to introduce various topics stemming from different fields in science. We hope to excite the students about science and show them how important it is to their everyday lives. This club also aims to provide free education to underserved communities.

Metal Complexes Of Redox Active Ligands, Alexandra Chaparro, Parker Keller

Chemistry & Biochemistry Student Scholarship

Alexandra Chaparro ’22, Major: Biochemistry

Parker Keller ’24, Major: Chemistry

Mentor: Dr. Maria Carroll, Chemistry and Biochemistry

Our research focuses on synthesizing and studying the properties of metal complexes that contain redox active ligands. Ligands are molecules or ions that can bind to a metal ion, and this particular class of ligands is interesting because they can either accept or lose electrons. We synthesized zinc complexes, in order to measure the reduction potentials of the ligands, which provide information about the ease with which they accept electrons. We then synthesized iron complexes and determined their structures. These complexes are potentially …

A Damaged Reputation: Nuclear Depictions In Entertainment Media, Alexander Cannon

Chemistry & Biochemistry Student Scholarship

This paper, originally written for Dr. Adamus Liotta in an honors chemistry class, explores the possibility of a significant influence over public common sense found in the depictions of entertainment media. Through careful analysis and interpretation of Godzilla, The Simpsons, Fallout, and Call of Duty, this paper finds a synergy throughout this diverse range of audience, medium and historical origin, which culminates in an effect much greater than the sum of its parts. This effect frames nuclear science, of any kind, in a hyperbolically catastrophic and horrific light, reinforcing an excessively cautious, pessimistic public perspective on nuclear technology …

Evaluation And Improvement Of Capillary Microextraction Of Volatiles Coupled To Gas Chromatography-Mass Spectrometry For The Analysis Of Ignitable Liquid Residues In Fire Debris, Michelle Nikole Torres

FIU Electronic Theses and Dissertations

A key aspect of fire debris analysis is the ability to extract the remnants of an ignitable liquid from a matrix with a high degree of reliability and sensitivity. Although there are several robust, standardized methods, there is no single technique universally applicable to casework. In this work a novel extraction technique – Capillary Microextraction of Volatiles (CMV) – has been applied, for the first time, for ignitable liquid residue (ILR) extraction. A 20-minute dynamic sampling laboratory protocol from traditional 1 L paint cans was established and optimized based upon ASTM guidelines. The development of new adsorption phases for CMV …

Insights Into The Deglacial Variability Of Phytoplankton Community Structure In The Eastern Equatorial Pacific Ocean Using [231Pa/230Th]Xs And Opal-Carbonate Fluxes, Danielle Schimmenti, Franco Marcantonio, Christopher T. Hayes, Jennifer Hertzberg, Matthew Schmidt, John Sarao

OES Faculty Publications

Fully and accurately reconstructing changes in oceanic productivity and carbon export and their controls is critical to determining the efficiency of the biological pump and its role in the global carbon cycle through time, particularly in modern CO₂ source regions like the eastern equatorial Pacific (EEP). Here we present new high-resolution records of sedimentary ²³⁰Th-normalized opal and nannofossil carbonate fluxes and [²³¹Pa/²³⁰Th]xs ratios from site MV1014-02-17JC in the Panama Basin. We find that, across the last deglaciation, phytoplankton community structure is driven by changing patterns of nutrient (nitrate, iron, and silica) availability which, in …

The Value Of Peer Mentoring Networks For Developing Leaders And Inspiring Change, Chrystal D. Bruce, Patricia M. Flatt, Sarah R. Kirk, Elizabeth Roberts-Kirchhoff, Hala G. Schepmann

2022 Faculty Bibliography

A peer-mentoring network, funded by the National Science Foundation ADVANCE program, profoundly impacted the career trajectory of five women chemistry faculty at predominantly undergraduate institutions. By providing each other support, encouragement, information, and accountability, we advanced our careers, became leaders in our own right, and implemented change at our institutions. To extend this benefit to more women STEM faculty, we have developed and implemented a model to support 74 faculty and administrators representing 51 institutions across the country.