A chelated-type colorimetric chemosensor for sensing Co²⁺ and Cu²⁺

A chelated-type colorimetric chemosensor TAMS (6,6′-((1E,1′E)-((thiobis(2,1-phenylene))bis(azanylylidene))bis(methanylylidene))bis(2-methoxyphenol)) was designed for sensing Co²⁺ and Cu²⁺ in aqueous solution. TAMS can detect Co²⁺ and Cu²⁺ by a clear color change of colorless to yellow with the low detection limits (0.66 μM for Co²⁺ and 0.88 μM for Cu²⁺). TAMS could quantify both Co²⁺ and Cu²⁺ in water samples. TAMS-Cu²⁺ could be distinguished from TAMS-Co²⁺ by using GSH. Based on the UV–vis experiments, ESI-mass, FT-IR, and theoretical calculations, the sensing mechanisms of TAMS to Co²⁺ and Cu²⁺ were demonstrated.