Ether Naphthotube Host-Guest Complexes and [2]Rotaxanes with Dications

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry

Background:

• Host-guest chemistry explores molecular recognition and self-assembly.
• Naphthotube derivatives are explored for their complexation abilities.

Purpose of the Study:

• Investigate the interactions between ether naphthotube and dication guests.
• Determine the binding affinities and driving forces of these host-guest complexes.
• Utilize these complexes for the synthesis of interlocked molecules.

Main Methods:

• Spectroscopic analysis (1H-NMR) to confirm complex formation.
• Isothermal Titration Calorimetry (ITC) to quantify binding thermodynamics.
• Synthesis of interlocked [2]rotaxanes via cationization and cycloaddition reactions.

Main Results:

• Ether naphthotube selectively forms 1:1 host-guest complexes with dications.
• Association constants range from 10^2 to 10^6 M^-1, primarily driven by enthalpy.
• Guest para-substitution influences binding affinity via electronic effects (linear free energy relationship).
• Two [2]rotaxanes were successfully synthesized using the host-guest complexes.

Conclusions:

• Ether naphthotube is an effective host for dication guests.
• Enthalpy is the primary driving force for host-guest complexation.
• The developed host-guest systems are valuable for constructing complex interlocked architectures.