Sensitive and Specific Guest Recognition through Pyridinium-Modification in Spindle-Like Coordination Containers.

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Coordination containers offer tunable frameworks for molecular recognition.
• Functionalized linkers are crucial for designing specific host-guest interactions.
• Intramolecular charge transfer (ICT) significantly influences photophysical properties.

Purpose of the Study:

• To synthesize and characterize a pyridinium-functionalized octanuclear zinc(II) coordination container.
• To investigate the selective recognition of guest molecules by the coordination container.
• To elucidate the role of ICT in the observed host-guest interactions and electronic property modulation.

Main Methods:

• Self-assembly of zinc(II) ions, p-tert-butylsulfonylcalix[4]arene, and a pyridinium-functionalized dicarboxylate linker (H2BrL1).
• Single-crystal X-ray diffraction for structural determination.
• Absorption and emission spectroscopy to study host-guest interactions and electronic property changes.

Main Results:

• Successful synthesis of the octanuclear zinc(II) coordination container (1-Zn).
• Demonstrated highly sensitive and specific recognition of 2-picolylamine.
• Observed drastic blueshifts in absorption and emission spectra upon guest binding.
• Attributed spectral changes to decreased ICT in the host and induced intermolecular charge transfer.

Conclusions:

• The designed zinc(II) coordination container exhibits selective guest binding capabilities.
• ICT modulation is key to the container's electronic property changes upon guest encapsulation.
• This work highlights the potential of coordination containers for developing responsive materials and sensors.