Redox induced reversible structural transformations of dimeric and polymeric phenanthroline-based copper chelates

Area of Science:

• Coordination Chemistry
• Materials Science
• Electrochemistry

Background:

• Phenanthroline ligands are versatile building blocks for metal complexes.
• Bridging ligands enable the formation of polynuclear metal species.
• Copper complexes are relevant in catalysis and materials science.

Purpose of the Study:

• Synthesize and characterize novel copper complexes with bridging phenanthroline ligands.
• Investigate the electrochemical and spectroelectrochemical properties of dimeric and polymeric copper complexes.
• Compare the behavior of these complexes with monomeric copper-phenanthroline species.

Main Methods:

• Synthesis of bridging phenanthroline ligands and their copper complexes.
• Electrochemical characterization using cyclic voltammetry (CV).
• Electrochemical quartz crystal microbalance (EQCM) for mass change analysis.
• UV-vis spectroscopy and spectroelectrochemistry for electronic property monitoring.

Main Results:

• Formation of a discrete dimeric copper complex ([Cu(2)(1)(2)](BF(4))(2)) and a coordination polymer ([2(Cu(2))(n)](BF(4))(n)).
• Redox cycling of the dimeric complex leads to precipitation and stripping.
• Electrooxidation of the coordination polymer induces reversible changes in copper coordination.

Conclusions:

• The redox state of copper centers dictates the structural integrity and behavior of the complexes.
• Coordination polymers exhibit reversible dissociation and regeneration linked to copper redox activity.
• These findings offer insights into designing redox-responsive coordination materials.