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 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. [ABSTRACT FROM AUTHOR]