Coexisting Mixed-Ligated Coordination Architectures as Hosts for Supramolecular Matchmaking with Customized Guests

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Coordination architectures offer tunable properties for molecular recognition.
• Ligand design is crucial for controlling the structure and function of metal-organic frameworks.
• Understanding host-guest interactions is key to developing selective binding systems.

Purpose of the Study:

• To synthesize and characterize novel mixed-ligated palladium coordination architectures.
• To investigate the guest-binding capabilities of architectures with different cavity exposures.
• To demonstrate a supramolecular matchmaking phenomenon based on selective guest binding.

Main Methods:

• Ensemble reaction of palladium precursors with bis-monodentate and tris-monodentate ligands.
• Isolation and characterization of 2D ([1]) and 3D ([2]) coordination architectures.
• Guest-binding studies with nonpolar and polar guests of varying sizes.

Main Results:

• Successfully synthesized two coexisting mixed-ligated palladium architectures, [1] (2D) and [2] (3D).
• Architecture [1] features an exposed cavity unsuitable for nonpolar guests, while [2] has a confined cavity for smaller nonpolar guests.
• Both architectures bind polar guests, but [2] has size limitations for larger polar guests.
• Demonstrated supramolecular matchmaking: [1] selectively binds larger polar guests, and [2] binds smaller nonpolar guests.

Conclusions:

• The charge and cavity characteristics of palladium coordination architectures dictate their guest-binding selectivity.
• The coexisting architectures [1] and [2] exhibit complementary binding preferences, enabling selective guest recognition.
• This work establishes a foundation for designing sophisticated supramolecular systems for targeted molecular capture.