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[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst
Published on: May 21, 2019
Square-pyramidal copper(ii)-Schiff base complexes with methoxy/ethoxy-phenolate and chloro-benzophenone substituents
Imdadul Haque1, Galib Abdullah1, Kashfia Azad Tuba1
1Department of Chemistry, Jahangirnagar University Dhaka-1342 Bangladesh enamullah@juniv.edu.
RSC Advances
|July 24, 2026
Summary
New copper(II) Schiff base complexes were synthesized and characterized. The free Schiff bases showed higher antioxidant activity than their copper complexes.
Area of Science:
- Coordination Chemistry
- Materials Science
- Organic Synthesis
Background:
- Schiff bases are versatile ligands in coordination chemistry.
- Copper complexes exhibit diverse applications in catalysis and medicine.
- Understanding structure-activity relationships is crucial for designing functional materials.
Purpose of the Study:
- To synthesize and characterize novel copper(II) Schiff base complexes.
- To investigate the structural, spectral, and electrochemical properties of the complexes.
- To evaluate the antioxidant activity of the Schiff bases and their copper complexes.
Main Methods:
- Synthesis of Schiff bases and copper(II) complexes.
- Single-crystal X-ray diffraction for structural analysis.
- Powder X-ray diffraction (PXRD), Differential Scanning Calorimetry (DSC), and Cyclic Voltammetry (CV) for material characterization.
- DPPH radical-scavenging assays for antioxidant activity evaluation.
- Density Functional Theory (DFT) and Time-Dependent DFT (TD-DFT) calculations for theoretical validation.
Main Results:
- Three Schiff bases (HL1-HL3) and their corresponding copper(II) complexes ([Cu(L1)2]–[Cu(L3)2]) were successfully synthesized.
- Structural analysis revealed square-pyramidal geometry around the Cu(II) center with trans-N,N' and O,O' configurations.
- PXRD and DSC confirmed phase purity and thermal behavior, while CV indicated two redox processes.
- Free Schiff bases exhibited superior antioxidant activity compared to the copper(II) complexes.
- Computational studies (DFT/TD-DFT) successfully reproduced experimental absorption spectra and molecular structures.
Conclusions:
- The synthesized copper(II) Schiff base complexes possess well-defined square-pyramidal structures.
- The electronic and structural properties are consistent between experimental and computational methods.
- While Schiff bases show promising antioxidant potential, their copper complexes have diminished activity, suggesting further research into their biological applications.
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