A new Schiff-base type selective fluorescent chemosensor for Cu2+

An original Schiff-base type fluorescent chemosensor 1-phenyl-3-methyl-5-hydroxypyrazole-4-carbaldehyde(benzoyl)hydrazone (H2L) for Cu2+ has been designed and synthesized. An obvious fluorescence quenching only for Cu2+ demonstrates that ligand H2L exhibits high selectivity and efficient signaling behavior toward micromolar concentration of Cu2+ compared with other metal ions. At the same time, the coordination form between ligand and Cu2+ is elucidated via crystal structure.