Chemistry
Presenter(s): Matthew Nwerem, Brian Han
Advisor(s): Dr. O. Maduka Ogba
Sulfur is an abundant, versatile element that exists in 14 unique forms and five oxidation states. Due to its many oxidation states and high electronegativity, sulfur is hungry for reactions that complete its octet or fill its empty d-orbital. Sulfur has been used medicinally since its antiquity, and now with more than 240 sulfur-containing US FDA approved drugs on the market, it’s worth continues to rise[1]. Since the early 20th century, nitrogen-containing sulfur (VI) compounds such as sulfonamides have been synthesized via either the oxidation of thiols or the substitution of sulfur (VI) chlorides. The former occurs under harsh conditions which limit the functional group compatibility. Sulfur (VI) chlorides precursors in the latter are thermodynamically unstable and are susceptible to hydrolysis and redox reactions. Sulfur (VI) fluorides have emerged as promising alternatives to the chloride analogs in the synthesis of sulfonamides. A recent study by Ball and coworkers has reported the use of stoichiometric calcium triflimide in the activation of sulfonyl fluorides; however, the mechanism of this process was unknown. We employed DFT computational techniques to (1) elucidate the calcium complex responsible for the S-F bond activation, (2) investigate the mechanism of the reaction, and (3) provide rationale behind the use of stoichiometric amount of calcium salt. Results from this study will be presented.