From Proton to Boron: The Lewis Analogs of Protonated Bronsted Super Acids

Isolation and characterization of highly reactive intermediates are crucial to understand the nature of chemical reactivity. Accordingly, the reactivity of weakly coordinating anions (WCA), usually used to stabilized cationic super electrophiles are of fundamental interest. When a variety of WCA are known to form stable sigma-complexes with a proton, inducing Bronsted super acidity, bis-coordinated weak-coordinated anions are much more elusive and considered as long-sought reactive species. In this work, the chemistry of borylated sulfate, triflimidate and triflate anions were scouted in details with the aim of synthetizing the unique analogs of protonated Bronsted superacids. Those complexes were formed by successive borylation with a 9-boratriptycene derived Lewis super acid paired with a weak coordinated anion, characterized in solution and in the solid state and exhibit unique structures and reactivities.

Automated summary

Isolation and characterization of highly reactive intermediates are important for understanding chemical reactivity. The chemistry of borylated sulfate, triflimidate, and triflate anions were studied in order to synthesize unique analogs of protonated Bronsted superacids. Complexes formed by borylation with a 9-boratriptycene derived Lewis super acid and a weakly coordinated anion were characterized in solution and in the solid state, exhibiting unique structures and reactivities.