High Sensitivity and Selectivity of Aminoantipyrine Schiff Base for the Recognition of Fe2+

An aminoantipyrine based chemosensor, (E)-1,5-dimethy1-44(2-(4-methylpyridin-2-yl)pyridin-4-y1) methyleneamino)-2-phenyl-1,2-dihydropyrazol-3-one(L), derived from 4-aminoantipyrine and 2-(4-methylpyridin-2yl) isonicotinaldehyde, was synthesized and the optical and metal sensing properties were investigated. The chemosensor L showed a selective colorimetric sensing ability for Fe' by changing colors from pale yellow to deep red in water-ethanol (9:1, V/V) medium, which facilitates the 'naked-eye' recognition of Fe' from other examined metal ions. The complex stoichiometry of Fe' to L (1:3, [FeL3](2+)) was obtained by Job's method. The association constant was determined to be 3.70x10(21) L-3.mol(-3). The present results indicate that the chemosensor L could be used as a selective, sensitive colorimetric sensor for Fe'. CCDC: 1817471, L.