Two new water-soluble copper(II)-dipeptide complexes: [Cu(glygly)(PyTA)]ClO₄·1.5H₂O (1) and [Cu(glygly)(PzTA)]ClO₄·1.5H₂O (2) (glygly = glycylglycine anion, PyTA = 2,4-diamino-6-(2′-pyridyl)-1,3,5-triazine and PzTA = 2,4-diamino-6-(2′-pyrazino)-1,3,5-triazine), utilizing two interrelated DNA base-like ligands (PyTA and PzTA), have been synthesized and characterized. The structure elucidation for 1 performed by single crystal X-ray diffraction showed a one dimensional chain conformation in which the central copper ions arrange in a five-coordinate distorted square-pyramidal geometry. Spectroscopic titration, viscosity and electrophoresis measurements revealed that the complexes bound to DNA via an outside groove binding mode, and cleaved pBR322 DNA efficiently in the presence of ascorbate, probably via an oxidative mechanism with the involvement of ˙OH and ˙O₂ ⁻. Notably, the complexes exhibited considerable in vitro cytotoxicity against four human carcinoma cell lines (HepG2, HeLa, A549 and U87) with IC₅₀ values ranging from 41.68 to 159.17 μM, in addition to their excellent SOD mimics (IC₅₀ ∼ 0.091 and 0.114 μM). Besides, multispectroscopic evidence suggested their HSA-binding at the cavity containing Trp-214 in subdomain IIA with moderate affinity, mainly via hydrophobic interaction. Further, the molecular docking technique utilized for ascertaining the mechanism and mode of action towards DNA and HSA theoretically verified the experimental results.

The ternary Cu(II) complex with 1,10-phenanthroline (phen) and L-valinate (L-Val) has been synthesized and investigated by elemental analysis, molar conductivity, UV/vis, IR, TG-DTG, and X-ray diffraction methods. The complex crystallizes in the triclinic space group P1 with two molecules in a unit cell of dimensions, a = 7.157(2) Å, b = 11.967(4) Å, c = 12.249(4) Å, α = 68.290(4)°, β = 77.813(5)°, γ = 83.490(5)°, V = 0.952.0(5) nm ų, R ₁ = 0.0297, and wR ₂ = 0.0396. The crystal contains two crystallographically independent [Cu(H₂O)(L-Val)(phen)]⁺ subunits Cu1 and Cu2, having a distorted square-pyramidal geometry with the same coordinated atoms around each copper center, the base plane being occupied by two nitrogen atoms of one phen, the amino nitrogen atom and one carboxylate oxygen atom from each independent L-Val moiety, and one water oxygen at an axial position. The SOD-like activity of the complex has been measured by means of modified nitroblue tetrazolium (NBT) photoreduction, and the IC₅₀ value (the concentration of the complex which causes the 50% inhibition of NBT reduction) of the complex for disproportionation of is 2.48 × 10⁻⁷M. The experimental results show that the complex is a potent superoxide dismutase mimic. CCDC: 267641.