A Mismatch Minimization Strategy for Sorting in [Pd₂L₂]⁴⁺ Macrocycles

Area of Science:

• Supramolecular Chemistry
• Coordination Chemistry
• Materials Science

Background:

• Molecular sorting strategies are crucial for predictable complex molecule and system formation.
• Ditopic bis-bidentate ligands with internal hydrogen-bonding sites offer unique assembly possibilities.
• Palladium(II) complexes are widely studied for their coordination and self-assembly properties.

Purpose of the Study:

• To design and synthesize ditopic bis-bidentate ligands for predictable molecular assembly.
• To investigate the self-assembly behavior of these ligands with palladium(II) ions.
• To develop a predictive model for palladium(II)-based molecular assemblies.

Main Methods:

• Synthesis of novel ditopic bis-bidentate ligands with internal hydrogen-bond donors/acceptors.
• Coordination studies of ligands with palladium(II) to form homoleptic and heteroleptic complexes.
• Structural analysis of assembled macrocycles using techniques like X-ray crystallography (implied).

Main Results:

• Predictable self-assembly of palladium(II) complexes was achieved, maximizing favorable hydrogen bonds.
• Unfavorable hydrogen:hydrogen and lone-pair:lone-pair clashes were minimized during assembly.
• Formation of two low-symmetry [Pd2(L)(L')]4+ macrocycles occurred integratively, driven by the disfavored nature of their homoleptic counterparts.
• Narcissistic and statistical sorting behaviors were observed in various combinations.

Conclusions:

• Ditopic bis-bidentate ligands effectively control palladium(II) assembly, leading to predictable outcomes.
• A scoring system based on observed assembly behavior can predict future palladium(II)-based systems.
• This approach offers a pathway for designing complex molecular architectures with high fidelity.