2005/03/01 by George J. P. Britovsek, Juri Ugolotti, Andrew J. P. White · 1 citation
Chemistry · #Crystallography and molecular interactions #Organoboron and organosilicon chemistry #Synthesis and characterization of novel inorganic/organometallic compounds
paper · doi:10.1021/om049091p
openalex publication_date 2005/03/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The pentafluorophenyl esters of bis(pentafluorophenyl)borinic acid (C 6 F 5 ) 2 BOC 6 F 5 ( 2 ) and pentafluorophenylboronic acid C 6 F 5 B(OC 6 F 5 ) 2 ( 3 ) have been prepared and characterized by multinuclear NMR and X-ray analysis. VT NMR studies have shown that restricted rotation around the B−O bond in 2 occurs below 193 K, corresponding to Δ G ⧧ = 35 kJ/mol for this process. This low barrier and the random torsion angles around the B−O bonds observed in the solid state structures of compounds 2, 3, and B(OC 6 F 5 ) 3 ( 4 ) suggest that these torsion angles are not related to pπ−pπ interactions between boron and oxygen, but more likely a consequence of the extensive intermolecular F−π interactions seen in the solid state structures. The Lewis acidity of 2, 3, and 4 has been compared with B(C 6 F 5 ) 3 ( 1 ), using various Lewis bases. All compounds 1 − 4 appear to be strong Lewis acids, whereby 4 interacts more strongly with hard bases whereas 1 binds more strongly to softer bases.