A Dual Purpose Strategy to Endow Gold Nanoclusters with Both Catalysis Activity and Water Solubility

Gold nanoclusters have attracted
extensive interest for
catalysis
applications in recent years due to their ultrasmall sizes and well-defined
compositions and structures. However, at least two challenges exist
in this emerging field. First, the steric hindrance of the ligands
inhibits the catalysis activity, and second, the mechanism underlying
water-phase catalysis using gold nanoclusters is often ambiguous.
Herein, we introduce a “kill two birds with one stone”
strategy to address these two challenges via the use of host–guest
chemistry. As an illustration, a novel adamantanethiolate-protected
Au40(S-Adm)22 nanocluster was synthesized, bound
with γ-CD-MOF, and then transferred to the HRP-mimicking reaction
system. The as-obtained catalyst exhibits excellent water solubility
and catalytical activity, totally different from the virgin Au40(S-Adm)22 nanoclusters. Further, the detailed
HRP-mimicking catalysis mechanism was proposed and supported by DFT
calculation. Another interesting finding is the unique structure of
Au40(S-Adm)22, which can be regarded as an Au13 icosahedron unit derived structure but different from the
widely reported icosahedron contained nanocluster where the Au13 icosahedrons are often centered. These novel, intriguing
results have important implication for the property tuning and practical
application of metal nanoclusters in the future.