Pyridyl DPP based soluble nanoaggregates for ratiometric/fluorescent detection of Cu2+/Hg2+ in water

A new diketopyrrolopyrrole amphiphile, namely 2-(2-(2-methoxyethoxy)-ethyl)- 3,6-di(pyridin-2-yl)-2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (PyDPP), is designed and synthesized as a novel ratiometric/fluorescent chemosensor for Cu²⁺/Hg²⁺. PyDPP forms soluble loose nanoaggregates by molecular self-assembly in water and maintains intrinsic bright fluorescence and color. The UV–vis absorption spectra data show that PyDPP nanoaggregates exhibits high sensitivity and selectivity toward Cu²⁺/Hg²⁺ among other metal cations in PBS (pH 7.4) solution. The reaction mechanism involved in PyDPP-Cu/Hg was investigated by MS, XPS and DFT calculation. The limit of detection of the present nanosensor for Cu²⁺ is calculated to be 87 nM. This research provides another view in the design and application of FONs nanosensor for heavy metal ions detection.