The chromogenic and fluorescent sensing properties for a water soluble polymeric chemosensor bearing rhodamine ethanediamine moieties with oxethyl (OCH2CH2) as a spacer

- The N−acryl−(2−oxyethyl) ethylenediamine−N′−(rhodamine B−yl) ethylenediamine (ARBEE) has been synthesized and characterized by FTIR, 1H NMR, EA and MS.
- The water-soluble copolymer, poly(AM-ARBEE) has been prepared by free radical precipitation copolymerization, which possesses oxyethyl (OCH2CH2) as a space group.
- The poly(AM-ARBEE) displayed sensitivity toward the detection of Cr3+, Fe3+, Hg2+ and Al3+ in aqueous solution over a wide range of tested metal ions with remarkably enhanced fluorescence intensities and also clear color changes from colorless to purple.

The water-soluble copolymer, poly(AM-ARBEE) has been prepared by free radical precipitation copolymerization of N−acryl−(2−oxyethyl) ethylenediamine−N′−(rhodamine B−yl) ethylenediamine (ARBEE) and hydrophilic comonomer (acrylamide, AM) and was characterized by FTIR and 1H NMR. The viscosity average molecular weight Mη of poly(AM-ARBEE) was with (7.07 × 103 g mol−1). The poly(AM-ARBEE) was a selective turn-on fluorescent and chromogenic chemosensor for Cr3+, Fe3+, Hg2+ and Al3+ over other metal ions. Titration curves of Cr3+, Fe3+, Hg2+ and Al3+ was constructed using rapid, cheap and widely available techniques of fluorescence spectroscopies. Furthermore, a colorimetric response from the polymeric chemosensor permitted the detection of Cr3+, Fe3+, Hg2+ and Al3+ by naked-eye due to the development of a purple color when these cations interacted with the copolymer in aqueous media.

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