Novel simple fluorescent sensor for nickel ions

Abstract A novel pyrazoline with benzimidazole substituent was conveniently synthesized, starting from a chalcone and 2-hydrazinylpyridine. The addition of Ni 2+ to ethanol solution of the synthesized pyrazoline resulted in a rapid color change from blue to green which allows the selective detection of Ni 2+ ion over a great number of other metal ions. The association constant for the 1:1 complex was determined to be 2.72 × 10 7  M −1 .