Chemistry Commons^™

Targeting Oncogenes: Development And Characterization Of Aurka And Her2 Inhibitors, Itzel Montoya

Chemistry Theses

Targeted inhibition of oncogenes has remained a key strategy in the development of more potent, effective, and less toxic therapeutic anticancer agents. Among the most clinically significant signaling pathways are those mediated by the Human Epidermal Growth Factor Receptor 2 (HER2) and Aurora Kinase A (AurKA). HER2 is a member of the ErbB receptor family that supports cell growth and proliferation through downstream signaling of the PI3K and MAPK pathways and is closely linked to more aggressive tumors and therapeutic resistance. AurKA is a protein kinase essential for mitotic spindle assembly, centrosome maturation, and other key processes in cell cycle …

Control Of Pore Nucleation And Rearrangement Kinetics During Aluminium Anodizing In Phosphoric Acid Electrolyte, Ilya V. Roslyakov, Nikita A. Shirin, Dmitry M. Tsymbarenko, Sergei N. Pavlov, Sergey E. Kushnir, Nikolay V. Lyskov, Kirill S. Napolskii

Journal of Electrochemistry

Anodic aluminium oxide (AAO) porous films with an interpore distance of several hundred nanometers are of great interest due to their unique interaction with visible and near-infrared light, and high thermal stability up to 1500 °C. These porous films are prepared by aluminium anodizing at high voltages in weak acids, leading to a slow kinetics of initial stages of porous structure formation. Here, we propose an approach to accelerate AAO formation in electrolytes based on weak acids such as phosphoric acid. Aluminium foils, pre-patterned using first anodizing under different conditions and subsequent selective dissolution of a sacrificial AAO layer, were …

Leveraging Molecular Mechanisms Of Desorption To Enhance Pfas Bioavailability In Contaminated Soils, Husam Kafeenah, Margaret D. Taiwo, Patrica Ivy Agorsor, Michael O. Eze

Chemistry Faculty Research & Creative Works

Per- and polyfluoroalkyl substances (PFAS) are known for their strong binding properties to soil matrices owing to their amphiphilic properties. While most studies focus on the search for novel PFAS bio degraders, our knowledge of sustainable biomolecules that could drive PFAS desorption and make them more bioavailable is limited. This study investigated the effectiveness of rhamnolipids and organic acids in desorbing PFAS compounds from contaminated soil. Rhamnolipids (25 mg/L) significantly enhanced the release of PFAS compounds from soil, achieving up to 90 % desorption. Acetic acid provided 60–90 % desorption efficiency for most of the PFAS studied, except for PFDA …

Applications For The Quasi-Atomic Orbital And Constrained Density Functional Theory Methods On Catalytic Reactions, Alvaro David Loaiza Orduz

LSU Doctoral Dissertations

Selective activation of C–O, C–H, and C–C bonds underpins biomass upgrading, alkane functionalization, and CO₂ conversion. Despite their importance, the electronic factors governing catalytic performance remain incompletely understood, and many industrial processes still rely on empirical trends or material-specific observations. This dissertation addresses this gap by applying density functional theory (DFT), thermodynamic decomposition, and electronic-structure analysis to identify unifying principles of reactivity across transition-metal phosphides, vanadate oxides, copper-based electrocatalysts, and mixed IrO₂–RuO₂ layers. This work examines how charge transfer, orbital localization, and ligand-induced perturbations control reaction pathways in diverse catalytic systems. C–O bond scission in 2-methyltetrahydrofuran (MTHF) and methanol was …

Regio- And Stereoselective Halogenation By An Iron(Ii)- And 2-Oxoglutarate-Dependent Halogenase In The Biosynthesis Of Halogenated Nucleosides, Philip M. Palacios, Xiaoyun Li, Simahudeen Bathir Jaber Sathik Rifayee, Haoyu Tang, Tatyana Karabencheva-Christova, Christo Christov, Wei-Chen Chang, Yisong Guo

Michigan Tech Publications

Iron(II)- and 2-oxoglutarate-dependent (Fe/2OG) enzymes have garnered strong research interest in past decades due to their ability to catalyze regio- and stereoselective C-H functionalization via a single reactive intermediate, the oxyferryl species. In addition to the hydroxylation reaction that is commonly observed, other reaction outcomes have also been discovered in Fe/2OG enzymes. Among them, halogenation has attracted much research effort with the goal of revealing the molecular determinants to favor halogenation over hydroxylation however, a full mechanistic picture is still missing. In this study, by investigating a recently identified Fe/2OG halogenase, AdeV, from the biosynthetic pathway of Adechlorin, we show, …

Comparative Expression Of Cgmp-Dependent Protein Kinase G (Pkg) From Plasmodium And Toxoplasma, Tsopmo Asaah

Theses, Dissertations and Culminating Projects

Malaria and Toxoplasmosis are life threatening diseases to humans. The search for a cure and control of these diseases is still one of the major challenges of scientists worldwide. In this research we focused on two Malaria species; Plasmodium bergei² (Pb) and Plasmodium falciparum¹ (Pf) and also on Toxoplasma gondii. Part of the life cycle of these organisms is regulated by the enzyme cyclic GMP-dependent protein kinase G (PKG)⁴. This is our drug target in this research. We believe that inhibiting this enzyme will be a great step in fighting these diseases. In this research, we devised a comparative study …

Vanadyl Phthalocyanine As A Low-Temperature/Low-Pressure Catalyst For The Conversion Of Fructose To Methyl Levulinate, Juan Luna, Mataz Alcoutlabi, Elizabeth M. Fletes, Helia Magali Morales, Jason Parsons

School of Integrative Biological & Chemical Sciences Faculty Publications

In this study, a vanadyl phthalocyanine was synthesized and characterized using XRD, FTIR, and XPS, confirming the successful metalation of the phthalocyanine ring. XRD analysis showed the vanadyl phthalocyanine crystallized in the P-1 crystal lattice, with unit cell parameters a = 12.058 Å, b = 12.598 Å, and c = 8.719 Å, and the lattice angels were 96.203°, 94.941°, and 68.204°. FTIR spectroscopy supported the metalation by the disappearance of the N-H stretch of the non-metalated phthalocyanine. The vanadyl phthalocyanine was tested as a heterogenous catalyst for the conversion of fructose into methyl levulinate in H2SO4–methanol and HCl–methanol systems. The …

Kinetic Analysis Of Hydrolysis And Hydrothermal Conversion Of Methyl Cellulose To Dodecane, Joseph Olembo Were

Electronic Theses and Dissertations

Environmental pollution due to emission of greenhouse gases and increasing global energy demand are some of the concerns associated Analysis with the use of fossil fuels. These concerns have triggered the exploration of sustainable and efficient methods for renewable energy production. One such method is the conversion of cellulosic biomass to hydrocarbon fuels using hydrogen bronze metals. Cellulose is the most abundant biomass globally, and thus its utilization can lead to more sustainable energy production. Previous studies have reported the conversion of cellulose to hydrocarbons at high temperatures and hydrogen pressure. This work focuses on the conversion of methyl cellulose …

Building A Framework For Analyzing Non-Linear And Multidimensional Kinetics, Mainak Dhar

Theses and Dissertations

Many materials exhibit multiple rates of molecular relaxation due to structural complexities. Standard linear and one-dimensional kinetic cannot extract all the necessary dynamic information about these systems. This dissertation contributes to an overarching scheme to develop new non-linear and multidimensional kinetic experiments to obtain this information. The studies span computation and experiments, picosecond to second timescales, and both single-molecule and pulsed-laser kinetics

Single-molecule kinetics experiments yield time series that contain information about unique structural and dynamic properties of materials. However, these time series are noisy, and data analysis is challenging. Parametric methods are computationally intensive and require strong, unverifiable assumptions …

Structural Impacts Of Canonical And Non-Canonical Oligonucleotide Modifications, Deepak Shrestha

Wayne State University Dissertations

Nucleic acids, including DNA (deoxyribonucleic acid) and RNA (ribonucleic acids), are the fundamental building blocks of living organisms. The events that cause modification of DNA/RNA are of interest because they impact the nucleic acid function. Targeting DNA is important for treating diseases such as cancer. Cisplatin (cisPt) is a well-studied drug that targets DNA and blocks replication, but its use is limited by adverse side effects and cellular resistance. Prevoius research addressed some of these challenges through development of platinum analogues such as carboplatin and oxaliplatin. Amino acid-linked platinum analogues (AAPt) are the focus of this thesis work. AAPt complexes …

Analysis And Optimization Of The Adsorption Of Lead Ions On A New Material Based On Silica Synthesized From Blast Furnace Slag, Toufik Chouchane, Ouahida Khireddine, Sabiha Chouchane, Mohamed Tayeb Abedghars, Hazem Meradi

Turkish Journal of Chemistry

A novel silica-based material (SBM), synthesized from chemically, thermally, and mechanically treated blast furnace slag (TBFS), was examined for its batch-mode lead adsorption capacity, based on various parameters. Physico-chemical examinations revealed that the formulation of the new material (SBM) consists mainly of silica, which represents 81.79% of its total composition. After modification, the measured specific surface area changed significantly, from 275.8 to 480.13 m2/g, with a point of zero charge (PZC) of approximately 3.4 on the pH scale. The experiment revealed that the driving factors (contact time, stirring speed, solution pH, temperature, and initial concentration) greatly influenced the improvement of …

Kinetic Characterization And Identification Of Key Active Site Residues Of The L-Aspartate N-Hydroxylase, Cree, Sydney B. Johnson, Hannah Valentino, Pablo Sobrado

Chemistry Faculty Research & Creative Works

CreE is a flavin-dependent monooxygenase (FMO) that catalyzes three sequential nitrogen oxidation reactions of L-aspartate to produce nitrosuccinate, contributing to the biosynthesis of the antimicrobial and antiproliferative nautral product, cremeomycin. This compound contains a highly reactive diazo functional group for which the reaction of CreE is essential to its formation. Nitro and diazo functional groups can serve as potent electrophiles, important in some challenging nucleophilic addition reactions. Formation of these reactive groups positions CreE as a promising candidate for biomedical and synthetic applications. Here, we present the catalytic mechanism of CreE and the identification of active site residues critical to …

Kinetic Characterization And Identification Of Key Active Site Residues Of The L-Aspartate N-Hydroxylase, Cree, Sydney B. Johnson, Hannah Valentino, Pablo Sobrado

Chemistry Faculty Research & Creative Works

CreE is a flavin-dependent monooxygenase (FMO) that catalyzes three sequential nitrogen oxidation reactions of L-aspartate to produce nitrosuccinate, contributing to the biosynthesis of the antimicrobial and antiproliferative natural product, cremeomycin. This compound contains a highly reactive diazo functional group for which the reaction of CreE is essential to its formation. Nitro and diazo functional groups can serve as potent electrophiles, important in some challenging nucleophilic addition reactions. Formation of these reactive groups positions CreE as a promising candidate for biomedical and synthetic applications. Here, we present the catalytic mechanism of CreE and the identification of active site residues critical to …

Kinetics Of Selenate Reduction Mediated By Underpotentially Deposited Cu On Polycrystalline Au Electrodes In Aqueous Perchloric Acid, Jonathan Strobl, Saurabh Pathak, Daniel Scherson

Faculty Scholarship

The reduction of selenate, SeO²₄⁻(aq),in 0.1 M HClO₄ solutions, induced by underpotential deposition, UPD, of Cu on polycrystalline Au electrodes was investigated using the rotating ring-disk electrode, RRDE, technique. Design and implementation of electrode potential-rotation rate protocols made it possible to determine the rates of SeO²₄⁻(aq)reduction as a function of Cu coverage, θCu, as determined by the Bruckenstein method (Swathirajan et al. J. Phys. Chem. 1982, 86, 2480–2485). In agreement with the results reported recently for Au(111) film electrodes (Strobl et al. Electrochimica Acta 2024, 493, 144,298), the reaction was found to proceed only for θCu above a critical value, …

Evaluation Of P(Hema-Co-Nipam) Hydrogels For Removal Of Methylene Blue From Aqueous Solution:Isotherm, Kinetic, And Thermodynamic Studies, Hayri̇ye Mi̇ne Antep, Müni̇re Nalan Demi̇r, Cevher Gündoğdu Hizliateş, Si̇mge Öztürk, Eli̇f Esen

Turkish Journal of Chemistry

In this study, a novel adsorbent material, poly (2-hydroxyethyl methacrylate-co-N-isopropyl acrylamide) (p(HEMA-co-NIPAM) hydrogel, was synthesized for the purpose of removing methylene blue (MB) from aqueous media. The synthesis of hydrogel was carefully conducted, and its properties were thoroughly examined using techniques such as Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The adsorption experiments conducted revealed a remarkable affinity of p(HEMA-co-NIPAM) hydrogel towards MB. The highest adsorption was observed when 0.05 g of the adsorbent were utilized, with optimal conditions at a pH of 6.0 and a temperature of 15 °C. This underscores the importance of …

Developing Methods For Analysis Of Chiral Small Molecules And D-Amino Acid Containing Peptides, Joshua I. Putman

Chemistry & Biochemistry Dissertations - Archive

This dissertation covers the development of methods to analyze chiral small molecules and d-amino acid containing peptides. The first section covers the development of liquid chromatographic chiral screening approaches for newly synthesized chiral molecules. The next part of the dissertation covers methodologies for the analysis of d-amino acid containing peptides. Lastly the bacterial degradation of three commonly used pesticides by bacteria harvested from Colorado potato beetles (Leptinotarsa decemliniata) is presented.

Twelve new azole compounds and eleven racemic ethanolamine derivatives were synthesized. These twenty-three compounds were evaluated using eight chiral columns, four macrocylic glycopeptides, a cyclodextrin derivative …

Computational Study Of Proton Transfer At Transition Metal Hydrides, Megan Ford

Honors Theses

Energy storage in the bonds of common chemical feedstocks is an attractive solution to the unreliability of wind and solar power due to its long term efficiency and easy recoverability. Energy is stored by reducing chemicals like ammonia, formic acid, and hydrogen, the reaction of which is dependent on a catalyst. To catalyze the reaction, the catalyst undergoes a slow proton transfer (PT) step to form what is known as a metal hydride. The sluggish kinetics of this step lower the effectiveness of the catalyst, and therefore must be better understood in order to improve the efficiency of energy storage …

Assessing Fixed-Node Diffusion Monte Carlo For Radical Polymerization Reaction Energetics, Timothy Brian Huber

Graduate Research Theses & Dissertations

The art of quantum chemistry is grounded to the discovery of a time efficient computational method that can capture the essential physics. Historically, the Hartree-Fock method, where an electron moves in the mean field of the other electrons, has provided the orbitals used to construct a single-reference Slater determinant and thus formed the basis for molecular orbital calculations. Kohn-Sham density functionals have become overwhelmingly popular among the chemistry community due to their low computational cost. However, their prediction of thermodynamic properties important in free radical polymerization has shown difficulty due to an artificial delocalization of electron density and spin contamination …

Studies Towards Mechanistic Understanding Of The Suzuki-Miyaura Catalyst-Transfer Polymerization, Mitchell Tyler Howell

Graduate Research Theses & Dissertations

Semiconducting organic conjugated polymers show major promise for the manufacturing of organic electronic and optoelectronic devices. Their utility comes from inherent conductivity, elasticity, processability and low weight paving the way towards novel materials and applications. The molecular weight, polydispersity, and precise incorporation of structural elements into the conjugated backbone are among the important parameters that affect a conjugated polymer’s mechanical and electrical properties. Therefore, precise control over such parameters provides a path for electronic materials with tunable properties tailored for a specific application. Recent success in this endeavor has been achieved with Suzuki-Miyaura Catalyst-Transfer Polymerization (SCTP) which is a transition …

Contributions Of Tunneling In 8Π-6Π Electrocyclic Cascade Reactions Of Bicyclo[4.2.0]Octa-2,4-Diene Moieties, Ishika Jain, Claire Castro, William L. Karney

Featured Student Work

Six-electron electrocyclic reactions usually require relatively high temperatures; however recent research has shown that such reactions can occur at significantly lower temperatures in biosynthetic and biomimetic pathways. Pathways resulting in bicyclo[4.2.0]octa-2,4-diene moieties arise from thermally allowed 8π-6π electrocyclization cascade reactions of 1,3,5,7-octatetraenes, as in the biosynthesis of endiandric acids, elysiapyrones, and numerous other natural products. We report multidimensional tunneling calculations to explore the possible contribution of heavy-atom tunneling (e.g. by carbon) to biosynthetic pathways and biomimetic syntheses, and thus to provide a more complete picture of biochemical kinetics. M06-2X/cc-pVDZ calculations on the 8π-6π cascade cyclizations of methylated octatetraene model systems …

Cationic Frontal Polymerization: Front Kinetics, Effects Of Additives, And Applications, Brecklyn R. Groce

LSU Doctoral Dissertations

Cationic frontal polymerization broadens the potential application of frontal polymerization by allowing for use of monomers such as epoxies and vinyl ethers. In this work, the effects of monomer and initiator composition and additives including fillers on front kinetics, along with applications of cationic frontal polymerization were investigated.

Using a radical-induced cationic frontal polymerization (RICFP) method with a superacid generating salt and a thermal radical initiator, the addition of vinyl ethers to epoxy formulations was studied, where an increase of front velocity was seen with increase of divinyl ether to epoxy ratio. Other aspects of vinyl ether systems, such as …

Interfacial Ligand Transformation On Plasmonic Nanostructures: Mechanistic Insights Unraveled By Plasmon-Enhanced Spectroscopy, Kexun Chen

Theses and Dissertations

We employ surface-enhanced Raman scattering (SERS) as an in situ spectroscopic tool, in conjunction with density functional theory (DFT) calculations, to develop a detailed mechanistic understanding of plasmon-driven photocatalytic reactions and heterogeneous transfer hydrogenolysis reactions of molecular adsorbates on metallic nanostructure surfaces. The excitation and decay of plasmon resonances in metallic nanostructures give rise to intriguing photophysical and photochemical effects, including the generation of hot charge carriers, local field enhancements, and photothermal transduction. These effects can be intentionally harnessed to drive or enhance interfacial molecular transformations along unconventional reaction pathways. The first part of the thesis focuses on the plasmon-driven …

A Critical Inter-Subunit Interaction For The Transmission Of The Allosteric Signal In The Agrobacterium Tumefaciens Adp-Glucose Pyrophosphorylase, Hiral Patel, Gabriela Martinez-Ramirez Ms., Emily Dobrzynski, Alberto A. Iglesias, Dali Liu, Miguel Ballicora

Chemistry: Faculty Publications and Other Works

ADP-glucose pyrophosphorylase is a key regulatory enzyme involved in starch and glycogen synthesis in plants and bacteria, respectively. It has been hypothesized that inter-subunit communications are important for the allosteric effect in this enzyme. However, no specific interactions have been identified as part of the regulatory signal. The enzyme from Agrobacterium tumefaciens is a homotetramer allosterically regulated by fructose 6-phosphate and pyruvate. Three pairs of distinct subunit-subunit interfaces are present. Here we focus on an interface that features two symmetrical interactions between Arg11 and Asp141 from one subunit with residues Asp141 and Arg11 of the neighbor subunit, respectively. Previously, scanning …

Cationic Polymer Coating Increases The Catalytic Activity Of Gold Nanoparticles Toward Anionic Substrates, Nicholas Langer, Mason Legrand, Ofer Kedem

Chemistry Faculty Research and Publications

Organic coatings on catalytic metal nanoparticles (NPs) typically hinder their activity due to the blocking of active sites. Therefore, considerable effort is made to remove organic ligands when preparing supported NP catalytic materials. Here, cationic polyelectrolyte coatings are shown to increase the catalytic activity of partially embedded gold nanoislands (Au NIs) toward transfer hydrogenation and oxidation reactions with anionic substrates compared to the activity of identical but uncoated Au NIs. Any potential steric hindrance caused by the coating is countered by a decrease in the activation energy of the reaction by half, resulting in overall enhancement. The direct comparison to …

V-Shaped Temperature Dependences And Pressure Dependence Of Elementary Reactions Of Hydroxyl Radicals With Several Organophosphorus Compounds, Xiaokai Zhang

Dissertations

Organophosphorus compounds have brought increasing attention since they are widely used as flame-retardants, which can take effect in combustion via reactions with reactive radicals. These reactions are influenced by variables such as temperature and pressure, resulting in a temperature and pressure dependent rate constant. Studying this reaction kinetics has great importance in both combustion reaction and atmospheric environment.

This study is focused on kinetics of several elementary reactions of combustion importance. The kinetics of hydroxyl radicals were studied using pulsed laser photolysis coupled to transient UV-vis absorption spectroscopy over the 295 - 837 K temperature range and the 1 - …

Halide Exchange And Transport In Halide Perovskite Lattices, Temban Acha Billy

Department of Chemistry: Dissertations, Theses, and Student Research

In recent years, metal-halide perovskites (MHPs) have risen quickly to prominence as promising materials across a variety of fields, from photovoltaics to optoelectronics in general. We show here a facile solution growth for creating a variety of mixed halide MAPbBr_3-xI_x crystals, which we will use to study halide exchange and transport in halide perovskites. We generated a calibration curve between the optical response and chemical composition in mixed Br/I MHPs at room temperature. All mixed Br/I MHP crystals were subjected to measurements of photoluminescence (PL) and Raman spectroscopy. A subset of mixed-halide MHP crystals exhibited multiple emission …

Facile Synthesis And Characterization Of Multi-Walled Carbon Nanotubes Decorated With Hydroxyapatite From Cattle Horns For Adsorptive Removal Of Fluoride, Walter Ojok, James P. Bolender, John Wasswa, Emmanuel Ntambi, William Wanasolo, Brenda Moodley

Chemistry and Biochemistry: Faculty Scholarship

Developing a new adsorbent for fluoride removal from cattle horn waste materials by a facile chemical method has shown great potential for fluoride removal. This paper reports the synthesis of multi-walled carbon nanotubes decorated with hydroxyapatite from cattle horns (MWCNT-CH) using a facile chemical method. Characterization studies using standard techniques showed that the composite is mesoporous with a rough morphology and contained MWCNTs uniformly encapsulated by the hydroxyapatite forming a crystalline MWCNT-CH composite. Optimization of fluoride adsorption by the as-synthesized composite using Response Surface Methodology (RSM) showed that a maximum fluoride removal efficiency of 80.21% can be attained at initial …

Predicting The Reactivities And Reaction Mechanisms Of Photochemically Produced Reactive Intermediates, Benjamin Barrios Cerda

Dissertations, Master's Theses and Master's Reports

Photochemically produced reactive intermediates (PPRIs) such as the hydroxyl radical, carbonate radical (CO₃^•-) singlet oxygen (¹O₂) and triplet state of chromophoric dissolved organic matter (³CDOM^*) are formed in sunlit natural waters upon photoexcitation of chromophoric dissolved organic matter (CDOM). PPRIs react with the organic compounds involved in key environmental processes, resulting in transformation products of smaller molecular weight than their parent compounds. Photochemical transformation of these key water constituents due to their reactions with PPRIs may pose potential effects on human and aquatic ecosystems. Consequently, there is a need …

Molecular Insights Into The Redox Of Atmospheric Mercury Through Laser Spectroscopy, Rongrong Wu Cohen

Theses and Dissertations

The widespread pollution of mercury motivates research into its atmospheric chemistry and transport. Gaseous elemental mercury (Hg(0)) dominates mercury emission to the atmosphere, but the rate of its oxidation to mercury compound (Hg(II)) plays a significant role in controlling where and when mercury deposits to ecosystems. Atomic bromine is regarded as the main oxidant for Hg(0) oxidation, known to initiate the oxidation via a two-step process in the atmosphere – formation of BrHg (R1) and subsequent reactions of BrHg with abundant free radicals Y, i.e., NO2, HOO, etc. (R2), where the reaction of BrHg +Y could also lead to the …

Calcium Bistriflimide-Mediated Sulfur (Vi)–Fluoride Exchange (Sufex): Mechanistic Insights Toward Instigating Catalysis, Nicholas Ball, Brian Han, Samuel R. Khasnavis, Matthew Nwerem, Michael Bertagna, O Maduka Ogba

Pomona Faculty Publications and Research

We report a mechanistic investigation of calcium bistriflimide-mediated sulfur(VI)–fluoride exchange (SuFEx) between sulfonyl fluorides and amines. We determine the likely pre-activation resting state─a calcium bistriflimide complex with ligated amines─thus allowing for corroborated calculation of the SuFEx activation barrier at ∼21 kcal/mol, compared to 21.5 ± 0.14 kcal/mol derived via kinetics experiments. Transition state analysis revealed: (1) a two-point calcium-substrate contact that activates the sulfur(VI) center and stabilizes the leaving fluoride and (2) a 1,4-diazabicyclo[2.2.2]octane additive that provides Brønsted-base activation of the nucleophilic amine. Stable Ca–F complexes upon sulfonamide formation are likely contributors to inhibited catalytic turnover, and a proof-of-principle redesign …