Affiliation:
1. School of Chemistry and Chemical Engineering Shandong University Jinan 250100 China
2. College of Chemistry Chemical Engineering and Materials Science Soochow University Suzhou 215123 China
3. Department of Chemistry Southern University of Science and Technology Shenzhen 518055 China
4. State Key Laboratory of Elemento-Organic Chemistry Nankai University Tianjin 300071 China
Abstract
AbstractThis report unveils an advancement in the formation of a Lewis superacid (LSA) and an organic superbase by the geometrical deformation of an organoboron species towards a T‐shaped geometry. The boron dication [2]2+ supported by an amido diphosphine pincer ligand features both a large fluoride ion affinity (FIA>SbF5) and hydride ion affinity (HIA>B(C6F5)3), which qualifies it as both a hard and soft LSA. The unusual Lewis acidic properties of [2]2+ are further showcased by its ability to abstract hydride and fluoride from Et3SiH and AgSbF6 respectively, and effectively catalyze the hydrodefluorination, defluorination/arylation, as well as reduction of carbonyl compounds. One and two‐electron reduction of [2]2+ affords stable boron radical cation [2]⋅+ and borylene 2, respectively. The former species has an extremely high spin density of 0.798e at the boron atom, whereas the latter compound has been demonstrated to be a strong organic base (calcd. pKBH+ (MeCN)=47.4) by both theoretical and experimental assessment. Overall, these results demonstrate the strong ability of geometric constraining to empower the central boron atom.
Funder
National Natural Science Foundation of China
Natural Science Foundation of Shandong Province
Taishan Scholar Foundation of Shandong Province