A new triazine bearing a pyrazolone group capable of copper, nickel, and zinc chelation

Interest in inorganic applications of triazines is growing. In this report, metal complexes of copper(ii), nickel(ii), and zinc(ii) and a novel class of chelates composed of a triazine ring substituted with a hydrazine group and pyrazolone are evaluated using spectrophotometric methods, single crystal X-ray diffractometry, and electrochemistry. Complexes with copper(ii) include a single chelate and chloride ion(s)/water to satisfy a trigonal bipyramidal coordination sphere. The nickel(ii) and zinc(ii) complexes are composed of two chelating groups that adopt an octahedral geometry around the metal ion. Irreversible redox activity was observed with the copper(ii) complex but no redox activity was observed with the ligand alone or zinc(ii) and nickel(ii) complexes. Use of the coumarin carboxylic acid assay shows that the ligand motif is capable of preventing redox cycling of copper in biological conditions and could thus serve as an antioxidant preventative agent. Cellular toxicity studies show that the new triazine molecule could have therapeutic applications in the μM concentration range based on the measured EC(50) = 1.183 ± 0.002 mM. Altogether this work shows that by merging triazine chemistry into inorganic compounds, there is potential to explore a range applications thanks to the new architecture.