Synthesis, Characterization and SOD Activities of IP-copper(II)-L-amino Acid Complexes

Four new ternary complexes: [Cu(IP)(L-Val)(H₂O)]ClO₄·1.5H₂O (1), [Cu(IP)(L-Leu)(H₂O)]ClO₄ (2), [Cu(IP)(L-Tyr)(H₂O)]ClO₄·H₂O (3) and [Cu(IP)(L-Trp)(H₂O)]ClO₄·1.5H₂O (4) have been synthesized and characterized by elemental analysis, molar conductivity, infrared absorption spectroscopy, electronic absorption spectroscopy and cyclic voltammetry, where IP=imidazo[4,5-f][1,10] phenanthroline, L-Val=L-valinate, L-Leu=L-leucinate, L-Tyr=L-tyrosinate and L-Trp=L-tryptophanate. Complex 3 was structurally characterized by X-ray diffraction method, which crystallizes in orthorhombic space group P2₁2₁2 in a unit cell of dimensions a=3.0567(4) nm, b=0.74079(9) nm, c=1.06198(13) nm, V=2.4047(5) nm³, Z=4, μ=0.1084 cm⁻¹. The SOD-like activities of catalytic dismutation of superoxide anions (O⁻₂) by the complexes were determined by means of modified nitroblue tetrazolium (NBT) photoreduction. The IC₅₀ values of complexes 1, 2, 3 and 4 are 0.072, 0.147, 0.429 and 0.264 µmol·L⁻¹, respectively.