Development of C3 symmetric triaminoguanidine-2-naphthol conjugate: aggregation induced emission, colorimetric and turn-off fluorimetric detection of Co2+ ion, smartphone and real sample applications

Abstract Herein, a simple aggregation induced emissive star shaped organic compound LH3 with 2-naphthol moiety was prepared by simple one-pot condensation reaction from low-cost chemicals. Aggregation induced emission (AIE) features of LH3 was established in DMF-H2O mixtures. Further, the cation sensing capability of the probe LH3 was examined towards various metal ions in DMF-H2O (Tris-HCl buffer solution pH 7.4, 8:2, and v/v) by using UV-vis and emission spectral experiments. The probe LH3 exhibits high selective and sensitive detection towards Co2+ ions over different metal ions via colorimetric as well as turn-off fluorometric fashion. Job’s plot analysis and mass spectral measurement confirms the formation of LH3-Co2+ complex (L-Co3) with 1:3 stoichiometric ratio. When the probe LH3 binds with Co2+ in 1:3 ratio, turn-off emission behavior was observed via chelation enhanced quenching (CHEQ) mechanism. To establish the practical application of the probe LH3, the detection of Co2+ ions present in real water was established. The visual noticeable color variation of probe LH3 upon addition of Co2+ ions have been clearly incorporated with a smartphone app via variation in RGB color values to build a on-site analysis of Co2+ ions.