Synthesis,Structure, and SOD‐like Activity of a Copper(II) Complex Containing a Bistriazole Group

The dinuclear complex Cu₂(HL)₂(H₂O)₂](ClO₄)₂ ( 1 ) H₂L = 5′‐(pyridin‐2‐yl)‐1‐H,2′‐H‐3, 3′‐bis(1, 2,4‐triazole)] was obtained and fully characterized. It exhibits a centrosymmetry configuration, in which each copper(II) ion is pentacoordinate with four nitrogen atoms of two triazole ligands and one oxygen atom from a water molecule. The net atomic charges distribution and atomic orbital contribution to frontier molecular orbitals were obtained using the Gaussian 98 program with Hartree‐Fock method at LANL2DZ level, indicating that the copper(II) ion has the potential to accept the electron of O₂ ^{· –}. The complex showed quasi‐reversible one‐electron Cu^II/Cu^I redox waves with redox potentials of –0.034 V. The SOD‐like activity (IC₅₀) of 1 was measured to be 0.18 ± 0.01 μM by xanthine/xanthine oxidase‐NBT assay at pH 7.8. The relatively high SOD activity suggests that the positive charge of protonated triazole can effectively steer O₂ ^{· –} to and from the active copper ion.