Two complexes (Cu, Zn) with 1,10-phenanthroline and a tridentate amino-Schiff-base: crystal structures, spectra, thermogravimetric analyses and superoxide dismutase activity

Abstract

Two transition metal (Zn, Cu) complexes with a Schiff base (salicylideneglycine) and 1,10-phenanthroline: (C₉H₇NO₃)Zn(C₁₂H₈N₂)(H₂O) (1) and (C₉H₇NO₃)Cu(C₁₂H₈N₂) (2) have been synthesized and characterized, including crystal structures, spectral characterization, thermogravimetric analyses and quantum chemistry calculations. X-ray crystallographic analysis shows the zinc to be six-coordinate mode, forming a slightly distorted octahedral geometry. The structure of 2 can be evaluated by the Addison distortion index (τ = 0.17), which indicates that the coordination environment of Cu is distorted slightly from square pyramidal (SP). The superoxide dismutase mimetic activity of the complexes was investigated by NBT-illumination. Complex 2 (IC₅₀ = 6.15 µM) has better SOD–like activity than 1 (IC₅₀ = 0.79 µM), although the SOD-like activity for 2 is not higher than some reported, it shows the possibility of SOD-like activity for the complexes with this amino-Schiff-base ligand (salicylideneglycine).

Keywords:

• Transition metal complexes
• Amino-Schiff-base
• Crystal structure
• Thermogravimetric analyses
• SOD-like activity

Acknowledgements

We express our sincere thanks to the National Natural Science Foundation of China (No. 20771051), Education Foundation of Liaoning Province (No. 05L212) and SRF 409 for ROCS, SEM for financial assistance.