Two new rhodamine-based fluorescent chemosensors for Fe3+ in aqueous solution

Abstract

Two new rhodamine-based fluorescent probes were synthesized and characterized by NMR, high resolution mass spectrometer (HR-MS) and IR. The probes displayed a high selectivity for Fe(3+) among environmentally and biologically relevant metal ions in aqueous solution (CH3OH-H2O = 3 : 2, v/v). The significant changes in the fluorescence color could be used for naked-eye detection. Job's plot, IR and (1)H NMR indicated the formation of 1: 1 complexes between sensor 1 and Fe(3+). The reversibility establishes the potential of both probes as chemosensors for Fe(3+) detection. The probe showed highly selectivity in aqueous solution and could be used over the pH range between 5 and 9. A simple paper test-strip system for the rapid monitoring of Fe(3+) was developed, indicating its convenient use in environmental samples.

Keywords: Fe3+; chemosensors; fluorescence; reversible; rhodamine.