Five-component, one-pot synthesis of an electroactive rotaxane comprising a bisferrocene macrocycle

Area of Science:

• Supramolecular Chemistry
• Organic Synthesis
• Electrochemistry

Background:

• Rotaxanes are mechanically interlocked molecules with potential applications in molecular machines.
• Hydrogen-bonding interactions are crucial for templating the formation of rotaxanes and pseudorotaxanes.
• Ferrocene derivatives are valuable for their redox activity and use in constructing complex molecular architectures.

Purpose of the Study:

• To describe the templated synthesis of a novel ferrocene-containing [2]rotaxane.
• To compare the efficiency of different hydrogen-bonding motifs in directing rotaxane assembly.
• To characterize the electrochemical behavior and solid-state structure of the synthesized rotaxane.

Main Methods:

• Templated clipping reaction between a ferrocene-grafted isophthalic acid derivative and 1,4-bis(aminomethyl)benzene.
• Comparative analysis of yields using various hydrogen-bonding templating strategies.
• Electrochemical measurements (e.g., cyclic voltammetry) to probe redox properties.
• Single crystal X-ray diffraction to determine the molecular structure.

Main Results:

• Successful synthesis of a [2]rotaxane featuring a ferrocene-grafted macrocycle encircling a hydrogen-bonding axle.
• Yields for rotaxane and pseudorotaxane formation varied significantly (0-41%) depending on the templating hydrogen-bonding motif.
• The electrochemical properties of the doubly ferrocene-decorated [2]rotaxane were investigated.
• The single crystal X-ray structure of the target [2]rotaxane was successfully determined.

Conclusions:

• The study demonstrates a viable route for synthesizing ferrocene-based [2]rotaxanes via templated clipping.
• The choice of hydrogen-bonding motif significantly impacts the efficiency of rotaxane synthesis.
• The characterized ferrocene-containing rotaxane offers a platform for exploring redox-active supramolecular systems.