Anionic guests in prismatic cavities generated by enneanuclear nickel metallacycles

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Nickel-azide systems are known for their magnetic properties.
• Polydentate aminated ligands offer versatile coordination possibilities.
• Metallacycles can form cage-like structures for molecular recognition.

Purpose of the Study:

• To synthesize and characterize novel nickel-nitrogen clusters.
• To investigate the structural diversity and topological features of these clusters.
• To explore the anion encapsulation capabilities of the resulting metallacycles.

Main Methods:

• Synthesis of polynuclear nickel complexes using polydentate aminated ligands.
• Characterization of cluster structures using X-ray crystallography.
• Investigation of anion binding through crystallographic and spectroscopic methods.

Main Results:

• A series of nickel-nitrogen clusters with unprecedented topologies were obtained.
• A unique family of {Ni9} metallacycles exhibiting cryptand-like cavities was identified.
• Selective encapsulation of azide and halide anions within these cavities via hydrogen bonding was demonstrated.

Conclusions:

• The combination of specific ligands and nickel-azide precursors yields complex cluster architectures.
• {Ni9} metallacycles represent a new class of host molecules for anion recognition.
• Hydrogen bonding plays a crucial role in the selective guest encapsulation within these supramolecular cages.