A Cyclic Phosphonium Ion with an Asymmetrically Substituted Selenide‐Stabilized Silicon Center: Synthesis, Structure, and Substituent Effects

Abstract

A new heterocyclic four-membered CPSeSi cation was synthesized in its racemic form by B(C 6 F 5 ) 3 -mediated ring-closing reaction starting from the hydrosilane precursor. The cation has an asymmetrically substituted silicon center, which is stabilized by a selenium-silicon bond. The phosphonium hydroborate and its precursor were characterized by single-crystal X-ray diffraction analysis and NMR spectroscopy. 77 Se, 31 P, and 29 Si NMR spectroscopic parameters proved to be sensitive probes for determining small electronic changes around the silylium-type center. Density functional theory (DFT) calculations of the ring-opening energy of the selenium-based cation gave insight into the stability of the Se-Si bond and revealed a stronger intramolecular stabilization of the silicon atom compared to a coordinating phosphane sulfide function. For the first time, the influence of a C 6 F 5 group at the silicon atom of these type of cations was also investigated, showing a slightly increased stabilization of the Se-Si linkage in the cyclic selenium-based cation.

A Powerful P−N Connection: Preparative Approaches, Reactivity, and Applications of P‐Stereogenic Aminophosphines

“…In addition, amino‐ and thiophosphates have recently been proposed as plausible molecules in early Earth scenarios [13] . Especially in the context of ligand design, oxidation of P(III) compounds with selenium has many advantages, as the 77 Se NMR spectroscopic parameters such as the 1 J P−Se coupling constant provide important information about the electronic nature of the new phosphines [7c,f,g] …”