A versatile and conformationally adaptable fluorene-based receptor for efficient binding of silver cation

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Coordination Chemistry

Background:

• Fluorene derivatives are versatile scaffolds in supramolecular chemistry.
• Designing receptors with conformational adaptability is key for selective ion binding.
• Silver cation binding requires specific receptor architectures.

Purpose of the Study:

• To synthesize a novel fluorene-based receptor capable of conformational adaptation.
• To investigate the binding efficiency and selectivity of the receptor for silver cations.
• To confirm the binding mechanism using spectroscopic and competition experiments.

Main Methods:

• One-pot synthesis of a fluorene-based receptor (1) from available precursors.
• 1H NMR and UV-vis spectroscopy to monitor silver cation binding.
• Competition experiments using tris[2.2.2]paracyclophane (2) and a model compound (3).

Main Results:

• The synthesized receptor (1) exhibits conformational flexibility, adopting deltaphane- or pi-prismand-like conformers.
• Receptor 1 binds a single silver cation with high efficiency (K ≈ 15,000 M-1).
• Binding was confirmed by spectroscopic data and validated through competition assays.

Conclusions:

• The fluorene-based receptor (1) demonstrates remarkable efficiency and conformational adaptability for silver cation binding.
• The study highlights the potential of such versatile receptors in supramolecular chemistry and ion sensing.
• The synthetic strategy offers a facile route to conformationally adaptable host molecules.