Arylpyrazole Schiff base: Synthesis and selective recognition of Cu2+

A series of novel arylpyrazole Schiff bases were designed and synthesized, and their structures were characterized by 1H NMR, 13C NMR, FT-IR, and elemental analysis. The UV-absorption and fluorescence emission spectra of arylpyrazole Schiff bases have investigated in pure DMF solution. The ion recognition experiment showed that both A1 and C1 could selectively recognize Cu2+ with two different ion recognize mechanisms: compound C1 coordinated with Cu2+ to form copper complexes, while A1 would take an oxidation cyclization reaction to generate compound 1,3,4-oxadiazole (A1–1) after coordinating with Cu2+. Density functional theoretical calculations were also used to explain the recognition mechanisms.