Synthesis, Characterization and Applications of Stibonium (III) Cationic Complex

Abstract

As a part of our fundamental research interest on the Lewis acid chemistry exhibited by main group Lewis acids, we chose to explore the activity of electron deficient pnictogen cationic species particularly, stibonium cation [1]+OTf-. In objective to synthesize [1]+OTf-, initially we successfully synthesized two different precursors, monochloro amino stibane complex, [1]-Cl and dichloro amino stibane complex, [1]-Cl2. Utilizing [1]-Cl, we successfully synthesized its respective cationic complex, [1]+OTf-. This [1]+OTf- was further utilized to exploit its reactivity and catalytic activity. Based on crystallographic evidence, it was revealed that [1]+OTf- is less likely to coordinate with weak donors like MeCN. Additionally, NMR spectroscopic studies of the preliminary catalytic reactions revealed that [1]+OTf- is capable of acting as a catalyst for simple organic transformation reactions like hydroboration and cyanosilylation for aldehydes. On the other hand, we also made use of [1]-Cl2 to generate its respective stibonium cationic and treated it with ItBu-NHC but surprisingly a dimer complex with Sb-O-Sb bridge connecting two abnormal centers of ItBu-NHC was obtained which is against the consensus yet an interesting species to carry out further investigative studies.