Adaptive Behavior of Dynamic Orthoester Cryptands

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Computational Chemistry

Background:

• Dynamic covalent chemistry in macrocycles is well-established for studying host-guest interactions.
• The constitutional dynamic chemistry of cryptands, however, remains largely unexplored.
• Orthoester bridgeheads offer a novel approach to dynamic cryptand systems.

Purpose of the Study:

• To investigate the unexplored constitutional dynamic chemistry of cryptands.
• To explore metal ion selection preferences within dynamic cryptand mixtures.
• To report the first self-assembly of a chiral orthoester cryptate.

Main Methods:

• Synthesis of cryptands featuring orthoester bridgeheads.
• Formation of dynamic mixtures of cryptand subcomponents.
• Metal ion binding studies with alkali metal cations (Li+, Na+, K+, Rb+, Cs+).
• Density Functional Theory (DFT) calculations for rationalization.

Main Results:

• Alkali metal ions exhibit distinct preferences for cryptands of specific sizes and donor numbers.
• Demonstrated metal ion-induced selection from a dynamic mixture of cryptand precursors.
• Successfully achieved the first self-assembly of a chiral orthoester cryptate.

Conclusions:

• Orthoester-based cryptands provide a versatile platform for dynamic host-guest chemistry.
• Metal ion templation can drive the selective formation of specific cryptand structures.
• The study opens new avenues for chiral cryptate synthesis and applications.