Pillar[5]arene‐Stabilized Silver Nanoclusters: Extraordinary Stability and Luminescence Enhancement Induced by Host–Guest Interactions

• Published in: Angewandte Chemie International Edition 2019-10, Vol.58 (44), p.15665-15670
• Main Authors: Muhammed, Madathumpady Abubaker Habeeb, Cruz, Laila Khalil, Emwas, Abdul‐Hamid, El‐Zohry, Ahmed M., Moosa, Basem, Mohammed, Omar F., Khashab, Niveen M.
• Format: Article
• Language: English
• Subjects: host–guest chemistry; molecular recognition; nanoclusters; pillararene; sensors
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201906740

Herein, we report the synthesis of a new class of functional silver nanoclusters (AgNCs) capped with pillar[5]arene (P5)‐based host ligands. These NCs are readily prepared through direct synthesis or ligand exchange synthesis and are stable at room temperature for over 4 months. The pillar[5]arene‐stabilized NCs (Ag29(LA‐P5)12(TPP)2) endorse reversible host–guest interactions with neutral alkylamines and cationic quaternary ammonium guests. This results in the formation of spherical assemblies with unparalleled changes in their optical properties including an astonishing circa 2000‐fold luminescence enhancement. This is the highest luminescence enhancement ratio reported so far for such atomically precise NCs. Our synthetic protocol paves the way for the preparation of a new generation of metal nanoclusters protected by macrocyclic ligands with molecular recognition and selectivity toward specific guests. Light pillars: Host–guest interactions of pillar[5]arene (P5)‐capped silver nanoclusters (Ag29(LA‐P5)12(TPP)2 with alkylamines and quaternary ammonium guest molecules resulted in the modulation of optical properties of the NCs, including an extraordinary circa 2000‐fold photoluminescence enhancement.