Year: 2025
Type: article
Abstract: High Resolution Image Download MS PowerPoint Slide The characteristic electronic structure of the phosphoryl group in phosphine oxides confers great stability on the P + –O – bond, in part because of back-bonding from O-based lone pairs into the P–C antibonding orbitals. The partial nature of this donation allows the O atom in the phosphoryl unit to exhibit Lewis basicity. This backbonding weakens as the atomic number of the pnictogen increases, which results in a significant enhancement in basicity for the heavier stiboryl congener. Here, we compare the ability of R 3 PnO (Pn = P, As, Sb) species to bind to main-group Lewis acids. As the steric bulk of the R group increases, R 3 PO and R 3 AsO lose this capacity; Dipp 3 PO and Dipp 3 AsO (where Dipp = 2,6-diisopropylphenyl) are unable to bind even the very strong Lewis acid B(C 6 F 5 ) 3 . In contrast, the enhanced basicity of the stibine oxides allows them to overcome this steric hindrance and form adducts, even in the case of the very hindered Dipp 3 SbO·B(C 6 F 5 ) 3 .
Source: Organometallics
Institution: University of California, Santa Cruz
Language: English
Subfield: Inorganic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,500
OpenAlex ID: W4414158144