Au 36 (SR) 22 Nanocluster and a Periodic Pattern from Six to Fourteen Free Electrons in Core Size Evolution.

An Au 36 (S- t Bu) 22 nanocluster (NC) is synthesized using the bulky tert -butyl thiol as the ligand. Single-crystal X-ray crystallography reveals that it has an Au 25 core which evolves from the Au 22 core in the previously reported Au 30 (S- t Bu) 18 , and the Au 25 core is protected by longer staple-like surface motifs. The new Au 36 NC extends the members of the face-centered cubic structural evolution by adding an Au 3 triangle and an Au 4 tetrahedron unit. Additionally, it is found that Au 36 emits near-infrared photoluminescence at 863 nm with a quantum yield (QY) of 4.3%, which is five times larger than that of Au 30 (S- t Bu) 18 -the closest neighbor in the structural evolution pattern. The higher QY of Au 36 is attributed to a larger radiative relaxation ( k r ), resulting from the structural effect. Finally, we find that the longer staple motifs lead to enhanced stability of Au 36 (S- t Bu) 22 relative to Au 30 (S- t Bu) 18 .