A biphenyl based coumarin fluorescent molecule, N,N’-bis(7-diethylamino-2-oxo-2 H-chromen-3-yl)methylene)biphenyl-2-2’-dicarbohydrazide (molecule 1) has been synthesized and characterised. Photophysical studies of 1 exhibit solvent polarity dependent absorption and emission maxima. Citrate capped gold nanoparticles (AuNPs) have been mixed with molecule 1 for the preparation of AuNPs/1 conjugate. The association constant of the AuNPs/1 conjugate has been calculated to 4.54 × 10⁴ M^− 1. The AuNPs/1 conjugate has been found to detect Hg²⁺ ion selectively by fluorescence enhancement. While addition of molecule 1 into the solution of AuNPs, fluorescence intensity of 1 quenched. On addition of several monovalent, divalent and trivalent metal ion into the solution of AuNPs/1 conjugate separately, there was no change in fluorescence intensity of 1 has been observed. However, upon addition of Hg²⁺ ion into the solution of AuNPs/1 conjugate, the fluorescence intensity enhancement occurred, indicating released of 1 from the surface of AuNPs and probably aggregation of AuNPs took place in presence of Hg²⁺ ion. The AuNPs/1 conjugate has been found to have a detection limit of 2.3 × 10^− 9 M for Hg²⁺ ion in aqueous solvent. Meanwhile, the AuNPs/1 conjugate have also been successfully applied for the determination of Hg²⁺ in real water samples.

合成并表征了基于联苯的香豆素荧光分子 N,N'-双(7-二乙氨基-2-氧代-2 H-苯并-3-基)亚甲基)联苯-2-2'-二碳酰肼（分子1 ） 。1的光物理研究显示出溶剂极性依赖的吸收和发射最大值。柠檬酸盐封端的金纳米粒子 (AuNP) 已与分子1混合，用于制备 AuNPs/ 1缀合物。 AuNPs/ 1缀合物的缔合常数经计算为 4.54 × 10 ⁴ M ^{- 1}。已发现AuNPs/ 1缀合物可通过荧光增强选择性检测 Hg ^{2+离子。当将分子}1添加到AuNPs溶液中时，1的荧光强度被猝灭。将几种单价、二价和三价金属离子分别添加到AuNPs/ 1缀合物溶液中时，没有观察到1的荧光强度的变化。然而，当将Hg ²⁺离子添加到AuNPs/ 1缀合物的溶液中时，荧光强度发生增强，表明1从AuNPs 表面释放，并且可能在Hg ²⁺离子存在的情况下发生了AuNPs 的聚集。已发现AuNPs/ 1缀合物对水性溶剂中的Hg ^{2+离子的检测限为 2.3 × 10 − 9} M。同时，AuNPs/ 1缀合物也已成功应用于实际水样中Hg ²⁺的测定。