Monitoring In Crystallo Elementary Steps at Cationic, Site-Isolated Pt Sites Using Solid-State NMR Signatures.

Understanding active sites and monitoring elementary steps in heterogeneous catalysis are central to establishing structure-activity relationships. In this context, solid-state molecular organometallic chemistry (SMOM) has emerged as an original approach in which reactive metal centers are site-isolated within a confined crystalline lattice. This enables in crystallo solid-gas transformations that are directly relevant to heterogeneous catalysis. However, experimentally determined metal speciation of reaction products and tracking changes in the coordination environment of the metal sites upon in crystallo reactions can be challenging when samples are not suitable for analysis by single-crystal X-ray diffraction or three-dimensional electron diffraction. Here, we report the development of SMOM approaches to generate isolated Pt sites in well-defined environments and demonstrate how 195Pt solid-state NMR spectroscopy enables reporting on the changes in the atomic-scale local structure of metal centers during in crystallo reactivity studies.