Resorcinarene bis-thiacrowns: prospective host molecules for silver encapsulation

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Organic Synthesis

Background:

• Resorcinarene derivatives are versatile macrocyclic hosts.
• Thiacrown ethers offer selective metal ion binding.
• Mixed-donor macrocycles combine properties of different donor atoms.

Purpose of the Study:

• Synthesize novel tetramethoxy resorcinarene bis-thiacrown hosts.
• Investigate the binding properties of these hosts with soft metal cations.
• Elucidate the binding modes and key interactions in host-guest complexes.

Main Methods:

• Organic synthesis of resorcinarene bis-thiacrowns.
• Nuclear Magnetic Resonance (NMR) spectroscopy for solution studies.
• X-ray crystallography for solid-state structure determination.

Main Results:

• Successful synthesis of mixed-donor resorcinarene bis-thiacrown hosts.
• Remarkable affinity for complexing silver cations (Ag+).
• Formation of 1:2 host-guest complexes in solution.
• Unanticipated endo- and exo-cavity binding of silver within the same host molecule in the solid state.
• Sulfur donor atoms identified as primary interaction sites for silver binding.

Conclusions:

• Resorcinarene bis-thiacrowns are effective ligands for soft metal cations like silver.
• The presence of sulfur donors is crucial for high-affinity silver binding.
• The study reveals diverse binding modes, highlighting the flexibility of these hosts.