Polyhydrido Copper Nanoclusters with a Hollow Icosahedral Core: [Cu 30 H 18 {E 2 P(OR) 2 } 12 ] (E=S or Se; R=nPr, iPr or iBu).

Although atomically precise polyhydrido copper nanoclusters are of prime interest for a variety of applications, they have so far remained scarce. Herein, this work describes the synthesis of a dithiophosphate-protected copper(I) hydride-rich nanocluster (NC), [Cu ₃₀ H ₁₈ {S ₂ P(OnPr) ₂ } ₁₂ ] (1 _H ), fully characterized by various spectroscopic methods and single-crystal X-ray diffraction. The X-ray structure of 1 _H reveals an unprecedented central Cu ₁₂ hollow icosahedron. Six faces of this icosahedron are capped by Cu ₃ triangles, the whole Cu ₃₀ core being wrapped by twelve dithiophosphate ligands and the whole cluster has ideal S ₆ symmetry. The locations of the 18 hydrides in 1 _H were ascertained by a single-crystal neutron diffraction study. They are composed of three types: capping μ ₃ -H, interstitial μ ₄ -H (seesaw) and μ ₅ -H ligands (square pyramidal), in good agreement with the DFT simulations. The numbers of hydrides and ligand resonances in the ¹ H NMR spectrum of 1 _H are in line with their coordination environment in the solid state, retaining the S ₆ symmetry in solution. Furthermore, two new Se-protected polyhydrido copper nanoclusters, [Cu ₃₀ H ₁₈ {Se ₂ P(OR) ₂ } ₁₂ ] (2 _H : R=iPr 3 _H : R=iBu) were synthesized from their sulfur relative 1 _H via ligand displacement reaction and their X-ray structures feature the exceptional case where both the NC shape and size are fully conserved during the course of ligand exchange. DFT and TD-DFT calculations allow understanding the bonding and optical properties of clusters 1 _H -3 _H . In addition, the reaction of 1 _H with [Pd(PPh ₃ ) ₂ Cl ₂ ] in the presence of terminal alkynes led to the formation of new bimetallic Cu-Pd alloy clusters [PdCu ₁₄ H ₂ {S ₂ P(OnPr) ₂ } ₆ (C≡CR) ₆ ] (4: R=Ph; 5: R=C ₆ H ₄ F).
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