Structured copper-hydride nanoclusters provide insight into the surface-vacancy-defect to non-defect structural evolution

Exploring the structural evolution of clusters with similar sizes and atom numbers induced by the removal or addition of a few atoms contributes to a deep understanding of structure–property relationships. Herein, three well-characterized copper-hydride nanoclusters that provide insight into the surface-vacancy-defect to non-defect structural evolution were reported. A surface-defective copper hydride nanocluster [Cu(28)(S-c-C(6)H(11))(18)(PPh(2)Py)(3)H(8)](2+) (Cu(28)-PPh(2)Py for short) with only one C(1) symmetry axis was synthesized using a one-pot method under mild conditions, and its structure was determined. Through ligand regulation, a 29(th) copper atom was inserted into the surface vacancy site to give two non-defective copper hydride nanoclusters, namely [Cu(29)(SAdm)(15)Cl(3)(P(Ph-Cl)(3))(4)H(10)](+) (Cu(29)-P(Ph-Cl)(3) for short) with one C(3) symmetry axis and (Cu(29)(S-c-C(6)H(11))(18)(P(Ph-(p)Me)(3))(4)H(10))(+) (Cu(29)-P(Ph-Me)(3) for short) with four C(3) symmetry axes. The optimized structures show that the 10 hydrides cap four triangular and all six square-planar structures of the cuboctahedral Cu(13) core of Cu(29)-P(Ph-Me)(3), while the 10 hydrides cap four triangular and six square-planar structures of the anti-cuboctahedral Cu(13) core of Cu(29)-P(Ph-Cl)(3), with the eight hydrides in Cu(28)-PPh(2)Py capping four triangular and four square planar-structures of its anti-cuboctahedral Cu(13) core. Cluster stability was found to increase sequentially from Cu(28)-PPh(2)Py to Cu(29)-P(Ph-Cl)(3) and then to Cu(29)-P(Ph-Me)(3), which indicates that stability is affected by the overall structure of the cluster. Structural adjustments to the metal core, shell, and core–shell bonding model, in moving from Cu(28)-PPh(2)Py to Cu(29)-P(Ph-Cl)(3) and then to Cu(29)-P(Ph-Me)(3), enable the structural evolution and mechanism responsible for their physicochemical properties to be understood and provide valuable insight into the structures of surface vacancies in copper nanoclusters and structure–property relationships.