Electronic Structures of Pt(0) Complexes and Atomically Precise Clusters from Solid-State ¹⁹⁵ Pt NMR Signatures

Metal clusters are of broad interest across fields in that they possess unique properties making them appealing for a variety of applications; additionally, they provide fundamental understanding of the structure, bonding, and reactivity of the extended metal systems at an atomic level. Pioneering studies on metal clusters were directed toward the rationalization of their (electronic) structure from symmetry considerations and computations. The need to relate these theoretical models to specific spectroscopic signatures of metal clusters in relation to their (electronic) structure has not yet been addressed. In this work, we studied a family of structurally related Ptn(0) species with different nuclearities (up to 15); we were able to show how 195Pt solid-state NMR can be used as a general tool to distinguish among metal sites in metal clusters and how their computed MO diagrams can be validated experimentally through the analysis of their NMR fingerprints. We applied this approach to known Pt phosphine/carbonyl ‘Chini’ clusters as well as to an unprecedented Pt5 square-pyramidal cluster. We propose that this approach can be extended to several other classes of metal clusters containing NMR-active centers, as well as (un)supported metal-based nanostructures.