Frustrated Lewis Pairs Comprising Nitrogen Lewis Acids for Si–H Bond Activation

Abstract

Abstract N‐heterocyclic nitrogen Lewis acids are a recent addition to the field of organic chemistry. Based on nitrenium cations, these acids where previously shown to generate Lewis adducts when combined with the appropriate Lewis bases. Herein, a triazinium‐based Lewis acid was combined with t Bu 3 P to generate a frustrated Lewis pair (FLP) capable of cleaving, for the first time, Si−H bonds in silanes. Whereas low yields were initially encountered owing to insufficient Lewis acidity, a new nitrenium‐based Lewis acid was synthesized, and its superior Lewis acidity was experimentally and computationally confirmed. A FLP based on this acid cleaved the Si−H bond in PhSiH 3 , generating the triazane product in a quantitative yield. This unprecedented N−H triazane was fully characterized by multinuclear NMR techniques and single‐crystal X‐ray crystallography. A new class of compounds, N‐H triazanes display the potential capacity to participate in hydride transfer reactions.