A silver-alkynyl cluster encapsulating a fluorescent polyoxometalate core: enhanced emission and fluorescence...

Area of Science:

• Inorganic Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Polyoxometalates (POMs) serve as versatile building blocks in supramolecular chemistry.
• Silver(I)-alkynyl clusters offer tunable electronic and optical properties.
• Europium-containing POMs can exhibit unique luminescence characteristics.

Purpose of the Study:

• To synthesize and characterize a novel silver(I)-alkynyl cluster templated by a polyoxoanionic core.
• To investigate the photophysical properties, specifically fluorescence, of the synthesized cluster.
• To explore the potential of the cluster for sensing applications, particularly for UV irradiation and sulfide ions.

Main Methods:

• Solvothermal synthesis of the silver(I)-alkynyl cluster using a [Eu(W5O18)2](9-) precursor.
• Single-crystal X-ray diffraction for structural elucidation.
• Spectroscopic analysis (UV-Vis absorption and fluorescence spectroscopy) to study photophysical properties.
• Investigation of fluorescence response to high energy UV irradiation and sulfide ion addition.

Main Results:

• Successful synthesis of a 42-core silver(I)-alkynyl cluster, [Ag42{Eu(W5O18)2}((t)BuC≡C)28Cl4][OH]·H2O (1), templated by [Eu(W5O18)2](9-).
• The cluster exhibits enhanced fluorescence compared to the POM precursor due to its hydrophobic shell.
• Fluorescence quenching is observed upon high energy UV irradiation (reduction of silver ions) and addition of sulfide ions.
• The fluorescence modulation demonstrates potential for sensing applications.

Conclusions:

• A novel silver(I)-alkynyl cluster with a unique structure and enhanced fluorescence has been synthesized.
• The cluster's fluorescence can be quenched by high energy UV light and sulfide ions, indicating its potential as a sensor.
• This work presents a new strategy for designing functional materials based on silver(I)-alkynyl clusters for detecting specific stimuli.