C3-symmetric triaminoguanidine based colorimetric and fluorometric chemosensor: Sequential detection of Zn2+/PPi, its RGB performance for detection of Zn2+ ion and construction of IMPLICATION logic gate

In this work, new ethyl(E)-2-cyano-3-(1H-pyrrol-2-yl)acrylate appended C-3 -symmetric star-shape triaminoguanidine based Schiff base (LH3) was designed and synthesized from simple synthons. New probe, LH3 was completely analyzed by H-1 NMR. C-13 NMR and mass spectrum. In the present probe LH3, effective pi-conjugated ethyl(E)-2-cyano-aciylate unit was introduced on the periphery of the pyrrole-triaminoquanidine conjugates by using carefully chosen building units. The probe LH3 shows high selectivity and sensitivity towards Zn2+- ion via colorimetric and fluorometric changes. The yellowish orange color of LH3 solution turned to wine red color upon addition of Zn2+ solution, along with red shifted absorption maxima from 450 nm to 550 nm, this indicates the formation of LH3-Zn2+ species. Job's plot and mass spectrum analysis confirms the formation of 1:3 stoichiometric complex between the LH3 and Zn2+ ions. Further this ensemble shows selective detection towards PPi anion over the other anions based on displacement metal ion approach. Hence, reversible colorimetric/emission response of LH3 towards Zn2+ and PPi ions via on-off-on manner could allow the construction of IMPLICATION logic gate functions. The practical efficacy of the probe LH3 was established by utilization of the probe for the detection of Zn2+ ions in real water sample analysis. Further, the significant noticeable colorimetric changes of the probe LH3 upon addition of Zn2+ ion have been successfully integrated with a smartphone app RGB color value to construct a real-time analysis of Zn2+ ions. (C) 2020 Elsevier B.V. All rights reserved.