Supramolecular Cages Based on a Silver Complex as Adaptable Hosts for Poly-Aromatic Hydrocarbons

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Coordination Chemistry

Background:

• Host-guest chemistry is crucial for molecular recognition and separation.
• Developing adaptable materials for selective binding of aromatic hydrocarbons is an ongoing challenge.
• Existing cage compounds and coordination networks have limitations in accommodating diverse guest molecules.

Purpose of the Study:

• To synthesize and characterize an adaptable silver complex (M) capable of hosting aromatic hydrocarbons.
• To investigate the structural transformations of M in the presence of different aromatic guests.
• To explore the potential of M as a novel adsorptive molecular material for polycyclic aromatic hydrocarbons (PAHs).

Main Methods:

• Synthesis and characterization of the L-shaped silver complex, AgLClO4 (M).
• Single-crystal and powder X-ray diffraction to analyze host-guest complex structures.
• Nuclear magnetic resonance (NMR) and fluorescence spectroscopy to study host-guest interactions in solution.

Main Results:

• The silver complex M exhibits adaptability, transforming from a closed to open crystalline structures upon guest inclusion.
• M successfully hosts a range of medium and large aromatic hydrocarbons, including PAHs.
• Host-guest complexes (M·nG) show structural confirmation via X-ray diffraction, with adaptable cavities fitting guest molecules.
• Solution studies indicate rapid exchange of guest molecules in and out of the host cavities.

Conclusions:

• The adaptable nature of M allows for flexible binding of diverse aromatic guests, overcoming limitations of traditional host materials.
• This adaptability provides insights into host-guest interaction strengths.
• M represents a new class of adsorptive molecular materials with significant potential for binding aromatics, particularly PAHs.