Atomically Precise Gold Nanoclusters: Synthesis and Catalytic Application - Atomically-Precise Methods for Synthesis of Solid Catalysts - page 127

d n 9 r 4 n g | 3

Figure 5.2 UV-visible spectra (a) and MALDI mass spectra (b) of Au nanoclusters
during the size-focusing process. Au-SG stands for the starting Au n (SG) m
mixture in aqueous solution. 10 min to 40 h indicates the time that
Au n (SG) m reacts with excess PhC 2 H 4 SH. The asterisk (*) shows a fragment
of Au 38 (SC 2 H 4 Ph) 24 which was caused by the MALDI method.
Adapted from ref. 22.

.

Figure 5.3 MALDI mass spectra of Au nanoclusters obtained from ligand exchange
of Au n (SG) m with PhC 2 H 4 SH (reaction for 10 min). The starting Au n (SG) m
nanoclusters were made (a) in methanol and (b) in acetone.
Adapted from ref. 22.

Guided by the size-focusing principle, other solvents were investigated, and
we found that acetone was indeed a good solvent for high-yielding synthesis
of Au 38 (SR) 24 as acetone solvent gave rise to a proper size distribution of
Au n (SG) m (Figure 5.3a) as the starting material for the size-focusing step. The
acetone-mediated synthesis of Au n (SG) m produced a dominant size range
from 8 to 18 kDa (charge z ¼ 1), while the methanol system produced a