Fluorescence and Colorimetric Anion Sensor Based on Pyrrole Derivative as Its Schiff Base

An anion probe molecule based on pyrrole derivative as its Schiff base (1,4-dicylaldehydepyrrole-2',4'-dinitrophenyl-hydrazone, 1) was designed and synthesized according to the binding site-signaling subunit approach. The compound was characterized by (1)H NMR, ESI-MS and elemental analyses. The binding properties of the probe with anions such as F(-), AcO(-), H(2)PO(4)(-), Cl(-), Br(-) and I(-) were evaluated by fluorescence, UV-Vis and (1)H NMR spectra. The results obtained indicated that the compound 1 was a probe for colorimetric detection of F(-), AcO(-), H(2)PO(4)(-), without resorting to any expensive spectroscopic instrumentation. In addition, addition of F(-), AcO(-), H(2)PO(4)(-) resulted in significant enhancement of the fluorescence of 1 at 413 nm, whereas the other anions tested had little influence on the fluorescence of 1. Job's plot showed the formation of 1/anions complexes of 1 : 1 stoichiometry.