Ag₂₀ Nanoclusters with Surface Azides as an Easily Functionalized Platform for Diverse Chemical Applications

Area of Science:

• Nanomaterials Science
• Surface Chemistry
• Organic Synthesis

Background:

• Modifying atomically precise nanocluster surfaces is challenging while preserving the core structure.
• Developing methods for functionalizing nanoclusters is crucial for their application.

Purpose of the Study:

• To synthesize and characterize novel silver nanoclusters (AgNCs) with surface azide moieties.
• To investigate the reactivity of these AgNCs in cluster surface strain-promoted azide-alkyne cycloaddition (CS-SPAAC) reactions.
• To demonstrate the ability to introduce new functionalities onto the AgNC surface via CS-SPAAC.

Main Methods:

• Synthesis of targeted Ag20 nanoclusters with specific azide ligands.
• Characterization using UV-vis, FT-IR, and NMR spectroscopies.
• Structural confirmation via single crystal X-ray diffraction (SCXRD).
• Reactivity screening using strained cyclooctynes for CS-SPAAC reactions.

Main Results:

• Two Ag20 nanoclusters, [CO3@Ag20(StBu)10(m-N3-C6H4COO)8(DMF)4] (1-m) and [CO3@Ag20(StBu)10(p-N3-C6H4COO)8(DMF)4] (1-p), were successfully synthesized.
• The presence of surface azide groups and the integrity of the nanocluster frameworks were confirmed.
• Clusters 1-m and 1-p demonstrated successful reactivity in CS-SPAAC reactions with strained cyclooctynes.

Conclusions:

• The synthesized AgNCs are amenable to modification via CS-SPAAC reactions.
• This approach allows for the introduction of new functionalities while maintaining the nanocluster core.
• Opens new avenues for the efficient modification of silver nanoclusters for diverse applications.