Eight-electron Pt/Cu superatom encapsulating three "electron-donating" hydrides.

Abstract

Hydrides in metal complexes or nanoclusters are typically viewed as electron-withdrawing. Several recent reports have demonstrated the emergence of "electron-donating" hydrides in tailoring the structure, electronic structure, and reactivity of metal nanoclusters. However, the number of such hydrides included in each cluster kernel is limited to one or two. There is even no structure model, neither theoretical nor experimental, for encapsulating a third electron-donating hydride into one cluster entity. Here, we present a structurally precise superatomic nanocluster, PtH₃Cu₂₃(iso-propyl-PhS)₁₈(PPh₃)₄ (PtH₃Cu₂₃), which contains three interstitial electron-donating hydrides. The molecular structure of PtH₃Cu₂₃ describes the encapsulation of a PtCu₁₂ core that contains three interstitial hydrides in a distorted anticuboctahedral architecture, in an outer sphere consisting of copper atoms and thiolate and phosphine ligands. Density functional theory calculations reveal that the three hydrides in PtH₃Cu₂₃ contribute their valence electrons to the cluster superatomic electron count of eight. In this regard, the cluster represents a rare Pt-included copper-hydride superatom with eight free electrons.