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Full-Text Articles in Inorganic Chemistry
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
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 …
Ion Separations: Achieving Selectivity Through Rational Design In Solvent Extraction And Crystallization Systems, Neil Justin Williams
Ion Separations: Achieving Selectivity Through Rational Design In Solvent Extraction And Crystallization Systems, Neil Justin Williams
Doctoral Dissertations
The selective separation of ions from aqueous solutions has been a difficult challenge to address in the separation sciences. The difficulties associated with selective separations of ions are due to a multitude of chemical and physical differences between them. Additionally, the term ions encompass both positively charged cations and their counter parts the negatively charge anions. The work covered in this dissertation discusses the difficulties encountered during the selective separation of both oxoanions and cations. Apart from the Introduction Chapter 1 and Conclusion Chapter 10, the selective separations oxoanions and cations will be discussed separately with the dissertation being …