Probing Substrate Diffusion in Interstitial MOF Chemistry with Kinetic Isotope Effects

<p>Metal-organic frameworks (MOFs) have garnered substantial interest as platforms for site-isolated catalysis. Efficient diffusion of small molecule substrates to interstitial lattice-confined catalyst sites is critical to leveraging unique opportunities of these materials as catalysts. Understanding the rate of substrate diffusion in MOFs is challenging and few <i>in situ </i>chemical tools are available to evaluate substrate diffusion during interstitial MOF chemistry. Here, we demonstrate nitrogen-atom transfer (NAT) from a lattice-confined Ru2 nitride to toluene to generate benzylamine. We use a comparison of the <i>intramolecular </i>deuterium kinetic isotope effect (KIE), determined for amination of a partially deuterated substrate, with the <i>intermolecular </i>KIE, determined by competitive amination of a mixture of perdeuterated and undeuterated substrates, to establish the relative rates of substrate diffusion and interstitial chemistry. We anticipate the developed KIE-based experiments will contribute to the development of porous materials for group-transfer catalysis</p>