Ligand-Free Sub-Nanometer Metal Clusters in Catalysis

Visible light enhanced catalytic activity of Aun subnanoclusters: the importance of d–sp interband transitions

“…Gold subnanoclusters (Au SNCs) constitute a special class of catalysts showing excellent activity in several organic transformations in solution, including C-C, C-Br or C-O bond formation. 1 These catalytic species consist of ligand-free clusters of 3-8 gold atoms, exhibiting molecular-type behaviour, with an electronic structure of defined molecular orbitals, in contrast to gold nanoparticles (Au NPs), which display an electronic band structure. The main drawback of Au SNCs is their transient existence, showing a large tendency to aggregate; however, they can be temporarily stabilized by a cooperative network of dispersive AuÁ Á ÁC-H and/or AuÁ Á Áp interactions, which improves their catalytic performance.…”