Electrochemical anion recognition with ferrocene functionalised macrocycles.

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Electrochemistry

Background:

• Cyclam ligands are macrocyclic compounds with diverse applications in coordination chemistry.
• Ferrocene-containing molecules offer unique redox properties for sensing applications.

Purpose of the Study:

• To synthesize and characterize novel redox-active cyclam ligands appended with ferrocenyl groups.
• To investigate the anion binding and sensing capabilities of these new ligands and their metal complexes.

Main Methods:

• Synthesis and structural characterization (including X-ray crystallography) of ferrocenylmethyl-appended cyclam ligands (L3 and L4).
• Electrochemical titrations to study anion binding through redox potential shifts.
• Isolation and structural characterization of the Zn(II) complex of L3.

Main Results:

• Successful synthesis and structural determination of L3 and L4, featuring ferrocenyl groups linked to cyclam macrocycles.
• Electrochemical evidence of hydrogen-bonding interactions upon anion binding, detected by shifts in the ferrocene redox potential.
• Demonstrated ability of L3, L4, and [ZnL3]2+ to electrochemically recognize chloride (Cl-) and acetate (AcO-) anions in MeCN-CH2Cl2 solutions.

Conclusions:

• The synthesized ferrocenylmethyl-cyclam ligands (L3, L4) and their Zn(II) complex exhibit electrochemical anion recognition properties.
• This sensing capability is specific to non-aqueous environments, being lost in aqueous solutions.
• The study highlights the potential of these redox-active macrocycles in developing electrochemical sensors for specific anions.