Prof. Michael Gerken from , Department of Chemistry and Biochemistry, University of Lethbridge, Lethbridge, Alberta, CANADA
C-CRAFT website: http://www.uleth.ca/research/centres-institutes/canadian-centre-research-advanced-fluorine-technologies
will give a guest lecture titled
Sulfur Tetrafluoride: New Perspectives on an Old Molecule
Abstract:
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.