Group II salts bound to weakly coordinating counterions, such as bistriflimide, have recently gained attention as Lewis acid catalysts in chemical reactions. These salts are particularly attractive because they are cheap, abundant, and non-toxic alternatives to transition metal catalysts typically used in modern organic synthesis. Catalyst scope data across several reports using these group II salts reveal reactivity differences when different group II metal ions are used; a deep understanding of metal ion effects on catalysis would foster efficient reaction design. To that end, we use a case study from recent experiments showing that calcium bistriflimide was effective in activating sulfur(VI) fluorides toward nitrogen-containing sulfur(VI) compounds via sulfur(VI)- fluoride exchange (SuFEx). In this work, significantly reduced yields were observed when magnesium bistriflimide was employed. Density functional theory (DFT) methods were used to compute and compare the SuFEx mechanism mediated by magnesium bistriflimide to that of calcium bistriflimide. Structural, energetic, and electronic properties of the activated species were analyzed to reveal the origins of the metal ioninduced differences in SuFEx reactivity mediated by group II Lewis acidic salts.

Metal ion effects on sulfur(VI)-fluoride exchange mediated by group II salts

Where thousands of chemistry professionals meet to share ideas and advance scientific and technical knowledge. Spring 2023 abstracts, posters, and presentations will launch at the end of March.

ACS Spring 2023

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.