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Keywords:

  • Crystal structure;
  • Copper;
  • Biomimetic complexes;
  • Superoxide dismutase

Abstract

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 CuII/CuI 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.