Prof. Michael Gerken from , Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, CANADA
will give a guest lecture titled
Sulfur Tetrafluoride: New Perspectives on an Old Molecule
Sulfur tetrafluoride has been known for more than 80 years and it is one of the textbook examples for the VSEPR rules. Recently, we obtained its solid-state structure and documented the Lewis-acid properties of SF4 towards organic bases. These bases include N-bases, such as pyridine, as well as O-bases, such as THF and cylcopentanone. Adducts of SF4 with N-bases can be solvolyzed by HF, generating salts that exhibit interesting interaction modalities in the solid state. It has been known for a long time that SF4 can also reacts with Lewis acids to form SF3+ salts. The two most stable salts, i.e., [SF3][AsF6] and [SF3][SbF6], have not been structurally characterized until our recent work. The study of the [SF3][SbF6] salt shows phase transitions between three different modifications. The SF3+ cation is thought to play a crucial role in deoxofluorination reagents of organic carbonyl compounds. We showed that SF3+ strongly interacts with organic bases. Solutions of [SF3][AsF6] in anhydrous HF act are superacidic, resulting in protonation of ketones, which were structurally characterized.