Highly selective colorimetric fluorescence sensor for Cu2+: Cation-induced 'switching on' of fluorescence due to excited state internal charge transfer in the red/near-infrared region of emission spectra

Article abstract of DOI:10.1016/j.tetlet.2010.08.048

A 1,8-naphthalimide-based colorimetric fluorescence perinone dye, receptor 1 is reported herein for the selective detection of Cu²⁺ over the other heavy and transition metal ions. Receptor 1 shows a strong colorimetric change from orange to purple and a dramatic enhancement of fluorescence intensity due to cation-induced excited state internal charge transfer during the sensing event, that is, a dual optical response that would facilitate naked-eye detection of Cu²⁺.