A 8-hydroxyquinoline-cyclodextrin conjugate as an efficient chelating agent for cobalt(II) and nickel(II) in neutral aqueous solution

Chelating agents offer a versatile and effective means of removing toxic metal ions from the human body. Mounting evidence suggests that exposure to nickel and cobalt causes a number of adverse nasal/pulmonary health effects, skin hazards and allergies. In this context, the development of chelatorsthat are able to bind nickel and cobalt with high stabilityconstants is clearly crucial. Herein, the interaction of cobalt(II) and nickel(II) with a 8-hydroxyquinoline-cyclodextrin conjugate was investigated in aqueous solution at neutral pH. This family of chelator under study is potentially relevantin the treatment of diseases related to metal dyshomeostasis. Stability constants for the cobalt(II) and nickel(II) complexeswere determined by competition experiments. The data indicate the formation of stable complexes, which were characterized by spectroscopic techniques. The collected information may provide new insights and suggest further strategiesfor the development of hydroxyquinoline derivatives for the control of cobalt and nickel toxicity.