Structural Characterization of Frustrated Lewis Pairs and Their Reaction Products Using Modern Solid‐State NMR Spectroscopy Techniques

Abstract

AbstractFrustrated Lewis pair (FLP) chemistry has provided a new strategy for small‐molecule binding and/or catalytic activation. The most prominent FLPs are based on intramolecular phosphaneborane adducts, the catalytic properties of which can be tailored over wide ranges of reactivity and selectivity. Advanced solid‐state NMR spectroscopic techniques, together with DFT calculations, can provide new structural insights in these systems. This review illustrates the utility of 31P and 11B NMR chemical shifts, 11B electric field gradient tensors, and 31P11B indirect and direct dipoledipole interactions for characterizing intramolecular boranephosphane FLPs. We demonstrate the potential of this method to 1) quantify the extent of boronphosphorus bonding interactions (and hence, the “degree of frustration”); 2) reveal specific structural details (i.e., boronphosphorus distances and other local geometric aspects) related to their catalytic activities; and (3) characterize products of FLP reactions with regard to molecular structure, stereochemistry, and aggregation properties in terms of internuclear distances, bonding connectivities, and orientational parameters.