DAB-Am-4 based colorimetric receptors for fluoride and pyrophosphate anions

Flexible four armed polypropylenimine tetraamine dendrimer (DAB-Am-4) core linked through urea moieties to a chromophore (aza group) gave rise to the colorimetric sensor 1 for fluoride ions, and a fluorophore (naphthyl group) attached to a similar assembly resulted in 2 which showed an excellent association constant with pyrophosphate anions.

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► Two new easy-to-prepare four armed dendrimer (DAB-Am-4) based neutral receptors are reported.
► Sensor 1 effectively recognizes biologically important F− and HP2O73− anion.
► To the best of our knowledge, the receptor 1 is the first naked-eye-detectable chemosensor containing four-armed dendritic core that permits discrimination between different anionic substrates as a result of disparate change in color.
► From the binding study experiments, receptor 2 can be termed as selective sensor for F− and HP2O73− anions.