Solvent Effects and Internal Functions Control Molecular Recognition of Neutral Substrates in Functionalized...

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Iron (Fe4L6) cage complexes represent a versatile platform for molecular recognition.
• Tuning solubility is crucial for studying host-guest interactions in diverse environments.
• Understanding the influence of internal functionalization and solvent effects is key to designing effective molecular recognition systems.

Purpose of the Study:

• To synthesize and characterize internally functionalized Fe4L6 cage complexes with lipophilic end groups.
• To investigate the molecular recognition capabilities of these cages towards neutral, nonpolar guests.
• To analyze the impact of internal functional groups and solvent polarity on guest binding affinities.

Main Methods:

• Synthesis of Fe4L6 cage complexes with tailored lipophilic end groups.
• Solubility testing in a range of solvents (e.g., HFIP, THF).
• Spectroscopic analysis (UV-Vis) to study host-guest interactions and internal functional group effects.

Main Results:

• Lipophilic end groups enabled cage solubility across a wide polarity spectrum.
• Micromolar guest binding affinities were observed for neutral guests.
• Polar internal groups enhanced binding in nonpolar solvents, while bulky aliphatic groups decreased affinity.
• High dielectric solvents favored binding, whereas low dielectric, high polarity solvents hindered guest recognition.

Conclusions:

• Fe4L6 cages with internal functionalization offer tunable molecular recognition properties.
• Solvent properties significantly influence host-guest complexation, with implications for solvent displacement effects.
• Optimizing host:guest interactions and solvent effects is critical for applications in supramolecular catalysis and biomimetic systems.