Characterization of H 2 ‐Splitting Products of Frustrated Lewis Pairs: Benefit of Fast Magic‐Angle Spinning

Proton spectroscopy in solid‐state NMR on catalytic materials offers new opportunities in structural characterization, in particular of reaction products of catalytic reactions such as hydrogenation reactions. Unfortunately, the 1 H NMR line widths in magic‐angle spinning solid‐state spectra are often broadened by an incomplete averaging of 1 H‐ 1 H dipolar couplings. We herein discuss two model compounds, namely the H 2 ‐splitting products of two phosphane‐borane Frustrated Lewis Pairs (FLPs), to study potentials and limitations of proton solid‐state NMR experiments employing magic‐angle spinning frequencies larger than 100 kHz at a static magnetic field strength of 20.0 T. The 1 H lines are homogeneously broadened as illustrated by spin‐echo decay experiments. We study two structurally similar materials which however show significant differences in 1 H line widths which we explain by differences in their 1 H‐ 1 H dipolar networks. We discuss the benefit of fast MAS experiments up to 110 kHz to detect the resonances of the H + /H − pair in the hydrogenation products of FLPs.