A Redox-active Cyclometalated Platinum Ring Enables Synthetic Post-processing of a [2]Rotaxane

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Coordination Chemistry

Background:

• Post-synthetic modification of mechanically interlocked molecules (MIMs) is crucial for creating complex molecular architectures.
• Developing new strategies for MIM modification remains an underdeveloped area in chemistry.

Purpose of the Study:

• To synthesize and characterize a novel [2]rotaxane featuring an emissive cyclometalated platinum(II) unit.
• To explore the post-synthetic modification of this rotaxane via redox state changes at the metal center.
• To investigate the structural, photophysical, and dynamic properties of the resulting modified MIMs.

Main Methods:

• Synthesis of a platinum(II)-containing [2]rotaxane.
• Electrochemical or chemical oxidation to alter the platinum center's oxidation state.
• Characterization using techniques such as NMR spectroscopy, mass spectrometry, and UV-Vis spectroscopy.
• Analysis of photophysical properties and molecular dynamics.

Main Results:

• Successful synthesis and characterization of a platinum(II) [2]rotaxane.
• Redox-induced transformation into a platinum(IV) [2]rotaxane or a platinum(III) [3]rotaxane featuring an unprecedented intermetallic Pt-Pt bond.
• Demonstration of distinct structural, photophysical, and shuttling dynamics for the different oxidation states.

Conclusions:

• The reported redox-driven post-synthetic modification strategy enables the construction of complex MIMs.
• This approach provides a versatile route to novel supramolecular assemblies with tunable redox properties.
• The findings open avenues for designing advanced functional materials based on interlocked structures.