Treatment of Silylene–Phosphinidene with Chalcogens Resulted Exclusively in the Formation of Silicon-Bonded Chalcogens

Abstract

Chalcogen-bonded silicon phosphinidenes LSi(E)−P−MecAAC (E=S (1); Se (2); Te (3); L=PhC(NtBu)2; MecAAC=C(CH2)(CMe2)2N-2,6-iPr2C6H3)) were synthesized from the reactions of silylene–phosphinidene LSi−P−MecAAC (A) with elemental chalcogens. All the compounds reported herein have been characterized by multinuclear NMR, elemental analyses, LIFDI-MS, and single-crystal X-ray diffraction techniques. Furthermore, the regeneration of silylene–phosphinidene (A) was achieved from the reactions of 2–3 with L′Al (L′=HC{(CMe)(2,6-iPr2C6H3N)}2). Theoretical studies on chalcogen-bonded silicon phosphinidenes indicate that the Si−E (E=S, Se, Te) bond can be best represented as charge-separated electron-sharing σ-bonding interaction between [LSi−P−MecAAC]+ and E−. The partial double-bond character of Si−E is attributed to significant hyperconjugative donation from the lone pair on E− to the Si−N and Si−P σ*-molecular orbitals.