Tetrameric and Dimeric [N⋅⋅⋅I⁺ ⋅⋅⋅N] Halogen-Bonded Supramolecular Cages

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Halogen Bonding

Background:

• Tripodal N-donor ligands are versatile building blocks in supramolecular chemistry.
• Halogen bonding offers a non-covalent interaction for constructing complex assemblies.
• Silver(I) complexes are frequently employed in the synthesis of coordination cages.

Purpose of the Study:

• To investigate the formation of halogen-bonded assemblies using tripodal N-donor ligands.
• To achieve selective synthesis of discrete tetrameric and dimeric halonium cages.
• To explore the transformation of silver coordination cages into halonium cages via cation exchange.

Main Methods:

• Synthesis of silver coordination cages using specific tripodal ligands (L1 and L2).
• Cation exchange reactions between silver cages and iodine (I2) to form halonium cages.
• Characterization of synthesized cages using NMR spectroscopy, ESI-MS, and single crystal X-ray diffraction.

Main Results:

• Selective formation of tetrameric I6L14 and dimeric I3L2 halonium cages was achieved.
• The choice of ligand (rigid L1 vs. flexible L2) dictated the cage stoichiometry.
• Successful transformation of silver coordination cages into corresponding halonium cages was confirmed.

Conclusions:

• Tripodal N-donor ligands can direct the formation of halogen-bonded assemblies.
• Halogen bonding provides a viable route to construct discrete halonium cages.
• The study highlights the utility of cation exchange for accessing novel supramolecular structures.