In or out? Adaptive metal binding by a diphosphine-based Zr metal-organic cage

Area of Science:

• Coordination Chemistry
• Materials Science
• Supramolecular Chemistry

Background:

• Metal-organic cages (MOCs) are porous materials with tunable properties.
• The development of MOCs with adaptable structures is crucial for advanced applications.
• Lantern-type MOCs offer unique confined environments for guest encapsulation and modification.

Purpose of the Study:

• To synthesize a novel lantern-type Zr-based MOC using a specific diphosphine ligand.
• To investigate the postsynthetic modification capabilities of the MOC with different metal precursors.
• To explore the adaptive structural responses of the MOC upon metalation.

Main Methods:

• Synthesis of Zr-P2N2 metal-organic cage using ditopic carboxylate linkers.
• Single-crystal X-ray diffraction for structural determination.
• Postsynthetic metalation with Palladium (Pd), Platinum (Pt), and Silver (Ag) precursors.

Main Results:

• Successful synthesis of the lantern-type Zr-P2N2 MOC.
• Demonstration of postsynthetic metalation with Pd, Pt, and Ag, forming heterobimetallic cages (Zr-P2N2-PdCl2, Zr-P2N2-PtCl2) and a hexasilver core (Zr-P2N2-Ag).
• Observation of adaptive structural changes, including linker flipping and inward/outward facing metal diphosphine groups, depending on the metal ion.

Conclusions:

• The Zr-P2N2 MOC exhibits remarkable adaptive structural behavior in response to metalation.
• The diphosphine groups within the MOC cavity can be functionalized, leading to diverse metal complexes.
• This adaptability opens new avenues for designing responsive and functional metal-organic cages.