An amide based dipodal Zn(2+) complex: nano-molar detection of HSO(4) (−) in a semi-aqueous system.

A new chromogenic dipodal Zn2+ complex (4) bearing an amide group has been synthesized. The anion binding profile of this sensor was investigated with fluorescence and UV-Vis spectroscopy. The receptor 4 has high affinity for HSO4 − with a binding constant of 3.5 × 104 M−1 and a detection limit of 50 nM. The binding ability was confirmed with spectroscopic methods and density functional theory calculation (DFT).