H-Aggregation of Squaraine Dye as Generic Colorimetric Molecules to Detect Cu²

An infrared squaraine dye was utilized to detect Cu²⁺ in solvents based on H-aggregates of squaraine dye. H-aggregates are a type of aggregation with enhanced photophysical properties compared to monomers. In the presence of a Ca²⁺ solution, F-Cl offers exceptional H-aggregators that can be transformed into monomers by adding Cu²⁺. Furthermore, this mode successfully demonstrated fluorescence changes in HeLa cells cultured in vitro after the addition of Ca²⁺ or Cu²⁺. A highly specific detection of Cu²⁺ was achieved using this transformation mode.