Small triiminopyrrolic molecular cage with high affinity and selectivity for fluoride

Area of Science:

• Supramolecular Chemistry
• Anion Recognition

Background:

• Developing selective sensors for small anions like fluoride is crucial in environmental and biological monitoring.
• Existing methods often struggle with selectivity in complex matrices.

Purpose of the Study:

• To synthesize a small molecular cage with exceptional selectivity and affinity for fluoride ions.
• To investigate the stability of the encapsulated fluoride under varying conditions.

Main Methods:

• Synthesis of a novel molecular cage (compound 4).
• Fluoride binding studies using techniques to assess affinity and selectivity against competing anions.
• Stability studies involving deprotonation of pyrrolic NH protons.

Main Results:

• The synthesized molecular cage (4) demonstrated high affinity and complete selectivity for fluoride.
• Selectivity was maintained down to the limit of detection, outperforming other small anions.
• The cage successfully retained the encapsulated fluoride anion even after partial deprotonation of pyrrolic NH protons.

Conclusions:

• The developed molecular cage represents a significant advancement in selective fluoride sensing.
• The stability of the fluoride-cage complex under deprotonation conditions broadens its potential applications.