Gold nanoparticles functionalized with deep-cavity cavitands: synthesis, characterization, and photophysical studies

Area of Science:

• Nanotechnology
• Supramolecular Chemistry
• Materials Science

Background:

• Gold nanoparticles (AuNP's) are widely used in various applications.
• Functionalization of AuNP's can alter their properties and introduce new functionalities.
• Cavitands are host molecules capable of encapsulating guest molecules.

Purpose of the Study:

• To functionalize AuNP's with deep-cavity cavitands for molecular encapsulation.
• To synthesize and characterize two types of functionalized AuNP's: one soluble in organic solvents and another in water.
• To investigate the host-guest complex formation and the effect of AuNP's on guest properties.

Main Methods:

• Synthesis of four new deep-cavity cavitands.
• Functionalization of AuNP's with thiol- and amine-terminated cavitands.
• Characterization of functionalized AuNP's using various analytical techniques.
• Investigation of host-guest complex formation and photophysical properties of encapsulated guests.

Main Results:

• Two types of functionalized AuNP's were successfully synthesized and characterized.
• Organic-soluble AuNP's formed 1:1 host-guest complexes with exposed guests.
• Water-soluble AuNP's formed 2:1 host-guest complexes, protecting guests from the solvent.
• Phosphorescence of encapsulated guests was quenched by AuNP's.
• Thiol-functionalized AuNP's exhibited stability, while amine-functionalized ones showed aggregation.

Conclusions:

• Deep-cavity cavitand-functionalized AuNP's can be synthesized with tunable solubility and host-guest properties.
• The encapsulation environment within AuNP's influences guest accessibility and photophysical behavior.
• Thiol-functionalized cavitands provide stable AuNP conjugates for potential applications.