Synthesis and characterization of a new diimine Schiff base and its Cu2+ and Fe3+ complexes: Investigation of their photoluminescence, conductance, spectrophotometric and sensor behaviors.

Abstract The newly synthesized Schiff base (HL 2 ) and its binary [ML 2 ] type of Cu(II) and Fe(III) complexes were characterized by various spectroscopic methods. The photoluminescence property of [CuL2 2 ] and [FeL2 2 ](NO 3) complexes, and HL 2 was studied in the absence and presence of Cu2+/Fe3+ ions in DMF: aqueous HEPES buffer (v: v, 1: 1, pH = 6.8). The conductance behaviors of compounds were investigated. The complexation reaction of the receptor with these ions, and the formation constants were determined in solution by spectrophotometric and conductometric method. The sensing ability of HL 2 against Cr3+, Fe3+, Ni2+, Zn2+, Cu2+, Co2+, Pb2+, Ba2+ and Ag+ ions were also evaluated in DMF: HEPES. High sensitivity and selectivity was achieved for Cu2+ and Fe3+ by UV–vis spectra in the presence of other ions, and it showed reversibility with EDTA. Job's method confirmed 2: 1 structure between HL 2 and Cu2+ and Fe3+. Receptor was applied for the ppm level detection of Fe3+ ion. Also, it sensed pH by "naked eye". Upon the addition of acid and base, its color instantly changed from yellow to colorless, corresponding to a blue shifting and disappearance in the absorption bands for acid and to orange for base. Graphical abstract Image 1 Highlights • Schiff base (HL2) and its binary Cu(II) and Fe(III) complexes were newly synthesized and characterized by various spectroscopic methods. • The photoluminescence property of [CuL22] and [FeL22](NO3) complexes, and HL2 was evaluated in the absence and presence of Cu2+/Fe3+ ions. • The complexation reaction of the receptor with these ions, and the formation constants were investigated in solution by spectrophotometric and conductometric method. • The sensing ability of HL2 against metal ions was also studied by naked eye and UV-vis spectra. [ABSTRACT FROM AUTHOR]