A Redox-Switchable, Allosteric Coordination Complex.

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Electrochemistry

Background:

• Development of molecular switches with tunable properties is crucial for advanced materials.
• Redox-switchable ligands offer a pathway to dynamic control over metal complex structures.
• The weak-link approach enables the synthesis of sophisticated molecular architectures.

Purpose of the Study:

• To synthesize and characterize a redox-regulated molecular tweezer complex.
• To investigate the allosteric regulation of coordination site accessibility by redox agents.
• To explore the electrochemical control over multiple distinct structural and electronic states.

Main Methods:

• Synthesis via the weak-link approach.
• Characterization using multinuclear NMR spectroscopy, cyclic voltammetry, and UV-vis-NIR spectroscopy.
• Structural determination via single-crystal X-ray diffraction (SCXRD) and density functional theory (DFT) calculations.

Main Results:

• Successful synthesis of a Pt(II) complex featuring a redox-switchable hemilabile ligand (RHL) with a ferrocenyl moiety.
• Demonstration of reversible switching between a fully closed and a semi-open state controlled by the ferrocene oxidation state.
• Identification and characterization of four distinct coordination states within the system, modulated by redox potential and structure.

Conclusions:

• The RHL-based system provides unprecedented electrochemical control over coordination site occupancy.
• This work establishes a new paradigm for designing dynamic coordination complexes with multiple, switchable states.
• The findings open avenues for stimuli-responsive materials and molecular devices.