Au<sub>36</sub>(SR)<sub>22</sub> Nanocluster and a Periodic Pattern from Six to Fourteen Free Electrons in Core Size Evolution
Yitong Wang, Christopher G. Gianopoulos, Zhongyu Liu, Kristin Kirschbaum, Dominic Alfonso, Douglas R. Kauffman, Rongchao Jin
Abstract
High Resolution Image Download MS PowerPoint Slide 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 .