Allyl-functionalized dioxynaphthalene[38]crown-10 macrocycles: synthesis, self-assembly, and thiol-ene...

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Materials Science

Background:

• Crown ethers are macrocyclic compounds known for their ability to bind ions and molecules.
• Pseudorotaxanes are mechanically interlocked molecular architectures with potential applications in nanotechnology.
• Dioxynaphthalene[38]-crown-10 (DNP38C10) is a specific type of macrocycle investigated for its host-guest properties.

Purpose of the Study:

• To synthesize novel allyl-functionalized DNP38C10 macrocycles.
• To evaluate the self-assembly of these macrocycles with methyl viologen into [2]pseudorotaxanes.
• To investigate the impact of allyl substitution on the binding thermodynamics and subsequent functionalization.

Main Methods:

• Synthesis of five DNP38C10 macrocycles with varying numbers of allyl moieties.
• Evaluation of self-assembly with methyl viologen using association constants.
• Thermodynamic analysis (enthalpic and entropic factors) of binding.
• Solution phase and solid-state analysis of macrocycles and complexes.
• Functionalization of allyl groups using thiol-ene click chemistry.

Main Results:

• Successful synthesis of allyl-functionalized DNP38C10 macrocycles.
• Comparable association constants between methyl viologen and both functionalized and unfunctionalized DNP38C10.
• Systematic variation in enthalpic and entropic contributions to binding free energy with increasing allyl substitution.
• Demonstration of facile functionalization of allyl groups via thiol-ene click chemistry.

Conclusions:

• Allyl functionalization of DNP38C10 macrocycles modulates binding thermodynamics with methyl viologen.
• The synthesized macrocycles serve as versatile platforms for creating more complex supramolecular structures.
• Thiol-ene click chemistry provides an efficient route for post-assembly modification of these systems.