A Novel Fluorescent Probe Based on Spiro[chromeno[2,3-c]pyrazole-4,1′-[2]benzofuran]-3′-one for Detecting Copper(II) ions in Aqueous Solution

A novel fluorescent probe, DHMP {7-(dibutylamino)-3-methyl-1 H ,3′ H -spiro[chromeno[2,3- c ]pyrazole-4,1′-[2]benzofuran]-3′-one} was designed and synthesized by condensation of 2-[4-(dibutylamino)-2-hydroxybenzoyl]benzoic acid with 5-methyl-2,4-dihydropyrazol-3-one. The ultraviolet absorption and fluorescence emission spectra of DHMP showed a clear pH dependence and highly selective and sensitive response to copper(II) ions in aqueous medium. The detection limit of Cu 2+ was estimated at 9.05 × 10 −8 M.