Controlling the Structure, Properties and Surface Reactivity of Clickable Azide‐Functionalized Au25(SR)18 Nanocluster Platforms Through Regioisomeric Ligand Modifications

摘要

Abstract To fine‐tune structure–property correlations of thiolate‐protected gold nanoclusters through post‐assembly surface modifications, we report the synthesis of the o, m, and p regioisomeric forms of the anionic azide‐functionalized [Au25(SCH2CH2‐C6H4‐N3)18]1? platform. They can undergo cluster–surface strain‐promoted alkyne–azide cycloaddition (CS‐SPAAC) chemistry with complementary strained‐alkynes. Although their optical properties are similar, the electrochemical properties appear to correlate with the position of the azido group. The ability to conduct CS‐SPAAC chemistry without altering the parent nanocluster structure is different as the isomeric form of the surface ligand is changed, with the [Au25(SCH2CH2‐p‐C6H4‐N3)18]1? isomer having the highest reaction rates, while the [Au25(SCH2CH2‐o‐C6H4‐N3)18]1? isomer is not stable following CS‐SPAAC. Single‐crystal X‐ray diffraction provide the molecular structure of the neutral forms of the three regioisomeric clusters, [Au25(SCH2CH2‐o/m/p‐C6H4‐N3]0, which illustrates correlated structural features of the central core as the position of the azido moiety is changed.