Synthesis, spectral, and X-ray structural characterization of mixed tren-barbitone nickel(II) complex grafted g-C₃N₄ for oxidative stress and antioxidant activities

A new complex, [Ni(Tren)(Barb)(H₂O)](Barb)(Barb-H)·2H₂O (NiC) {Tren = tris(2-aminoethyl)amine and Barb = 5,5-diethlybarbiturate}, has been synthesized and characterized. The nickel(II) complex was grafted to g-C₃N₄, forming NiC@g-C₃N₄. The obtained NiC complex and its hybrid material NiC@g-C₃N₄ were characterized by FT-IR, TGA-DSC, UV–vis, SEM-EDX, and XRD. Single crystal X-ray crystallography shows that NiC exhibits NiN₅O octahedral geometry. The results also show that the complex molecules are connected via N–H⋅⋅⋅⋅O hydrogen bonds. The complex NiC and NiC@g-C₃N₄ show oxidative stress effects on in vivo experiments. They also showed an increase in tissue damage markers that are represented by increase in tissue levels of malondialdehyde (MDA) in brain, liver, kidney and heart. Both materials showed inhibitory activity for examined antioxidants such as glutathione-S-transferase (GST), superoxide dismutase (SOD), glutathione (GSH) and glutathione reductase (GSH-R). The destructive effects were clearer for the NiC@g-C₃N₄ composite in liver, brain and kidney, respectively. The grafting of NiC complex in g-C₃N₄ is responsible for improving the catalytic activity of the compound, due to the synergistic effect of both components and facile recovery, as well recycling of the catalyst.