A Multi-Stimuli Transformational Network of Benzil-Based Pd(II) Assemblies.

Area of Science:

• Coordination chemistry
• Supramolecular chemistry
• Materials science

Background:

• Precise control over supramolecular topology and nuclearity in coordination-driven self-assemblies is challenging.
• Ligand design is crucial for directing self-assembly outcomes.

Purpose of the Study:

• To introduce a flexible ligand (L^A) capable of adopting multiple conformations.
• To explore the formation of diverse palladium(II) assemblies with varying topologies and nuclearities.
• To investigate stimuli-responsive transformations of these assemblies.

Main Methods:

• Synthesis of ligand L^A based on a benzil backbone.
• Coordination of L^A with Pd(II) to form homoleptic and heteroleptic assemblies.
• Characterization of resulting supramolecular structures.
• Post-assembly modification via ligand condensation.

Main Results:

• Formation of mononuclear (PdL^A₂) and cage (Pd₂L^A₄) homoleptic assemblies.
• Synthesis of heteroleptic assemblies (cis-Pd₂L^A₂L^C₂, Pd₃L^A₂L^D₄) with secondary ligands.
• Demonstration of interconversion and guest-induced transformations between architectures.
• Post-assembly conversion to a rigid quinoxaline-based complex (PdL^B₂).

Conclusions:

• Ligand conformation and assembly environment dictate structural outcomes and reactivity.
• Demonstrated a stimuli-responsive system for dynamic control over supramolecular structures.
• Highlighted the potential for mimicking natural systems' control over reactivity via confinement and allosteric effects.