The Synthesis Of Bipyridine Ruthenium Complex And Their Applications For Photoelectrochemical Detection Of Hg²⁺

Mercury and its compounds are well known toxic chemicals with great threats to human health.Exposure to these chemicals by the consumption of contaminated food products results in toxicity to the central nervous system.To control the use of mercury and its compounds,a simple,fast,and sensitive method for detecting them is required.In this thesis,a photoelectrochemical method,which has been well demonstrated to have high sensitivity,low cost,and minimized instruments,was developed for the detection of mercury ions,which was based on a synthesized thiocyanate substrated Ru?II?polypyridine complex and Ti O₂ nanocomposites.The detailed information is as follows:1)Synthesis of Ru?II?complexes and the investigation of their anchoring stability to TiO₂ in aqueous solutionsA series of Ru?II?polypyridine complexes with either different number of anchoring groups or different kinds of ligands were synthesized,coupled with TiO₂ nanoparticles,and characterized by the methods of 1H NMR,mass spectrum,electrochemsitry,UV-vis absorption spectrum,fluorescent emission spectrum,and photoelectrochemical methods.Among them,the complex denoted as dye3,showed the highest photo-to-electron conversion efficiency and good anchoring stability to TiO₂ nanoparticle.By comparison,its high photo-to-electron conversion efficiency may be ascribed to the presence of thiocyanate which could assist the electron-charge separation.And its good anchoring stability was ascribed to the presence of two acrylic acid anchoring groups and suitable hydrophibicity.2)Highly sensitive and selective photoelectrochemical detection of Hg²⁺ by dye3 and TiO₂ nanocompsitesDue to its high photo-to-electron conversion efficiency,the dye3-TiO₂ nanocomposites were used for the photoelectrochemical detection of Hg²⁺,depending on the fact that the coordination interaction between Hg²⁺ and the SCN-could retard the electron-hole seperation and decreased the photocurrents.Under optimal conditions,the as-fabricated PEC sensor showed high sensitivity towards the detection of Hg²⁺,with a wide linear range of 10-7¹0-11 and a low limit of detection of 1.1 pM.In addition,the sensor also showed good selectivity,which could exclude the interference from other metal ions.