Constrained Phosphine Chalcogenide Selenoethers Supported by peri-Substitution

Anna E Tarcza; Alexandra M Z Slawin; Cameron L Carpenter-Warren; Michael Bühl; Petr Kilian; Brian A Chalmers

doi:10.3390/molecules28217297

Constrained Phosphine Chalcogenide Selenoethers Supported by peri-Substitution

Molecules. 2023 Oct 27;28(21):7297. doi: 10.3390/molecules28217297.

Authors

Anna E Tarcza¹, Alexandra M Z Slawin¹, Cameron L Carpenter-Warren¹, Michael Bühl¹, Petr Kilian¹, Brian A Chalmers¹

Affiliation

¹ EaStCHEM School of Chemistry, University of St Andrews, North Haugh, St Andrews, Fife KY16 9ST, UK.

Abstract

A series of phosphorus and selenium peri-substituted acenaphthene species with the phosphino group oxidized by O, S, and Se has been isolated and fully characterized, including by single-crystal X-ray diffraction. The P(V) and Se(II) systems showed fluxional behavior in solution due to the presence of two major rotamers, as evidenced with solution NMR spectroscopy. Using Variable-Temperature NMR (VT NMR) and supported by DFT (Density Functional Theory) calculations and solid-state NMR, the major rotamers in the solid and in solution were identified. All compounds showed a loss of the through-space J_PSe coupling observed in the unoxidized P(III) and Se(II) systems due to the sequestration of the lone pair of the phosphine, which has been previously identified as the major contributor to the coupling pathway.

Keywords: DFT calculations; NMR; peri-substitution; phosphorus; rotational conformation; selenium; single-crystal X-ray structures.

Grants and funding

This research received no external funding. We are grateful to the University of St Andrews School of Chemistry Undergraduate Project grants. Calculations were performed at a local high-performance computing facility maintained by H. Fruchtl.