Study On Synthesis And Ion Sensing Properties Of 4,5-disubstituted Ferrocene-imidazole Derivatives

Metal ions have been widely concerned because they play an important role in the ecosystem.Microscopically,metal ions are not only involved in the hard tissues that make up the organism,but also involved in various complex biochemical processes in the organism,such as material transportation,energy conversion,information transfer and metabolic regulation.Human activities have led an increase of heavy metal ions in soil and rivers.The metal ions accumulated and accumulated in crops and aquatic organisms could finally cause serious harm to humans through the food chain.Many scholars have designed and studied small organic molecules for detection of metal ions.These organic molecules are usually composed of three parts,namely,a recognition group,a connecting arm and a response group.The recognition group is a group that can bind with substrate;the response group is a signal unit that emits optical or electrical signals;the connecting arm serves as a bridge to connect the recognition group and the response group.In this paper,we have synthesized three multiple nitrogen containing heterocyclic ferrocene imidazole derivatives using aromatic heterocyclic?-diketone and ferrocene formaldehyde as raw materials.These three compounds were used as ion probes for selective detection of metal ions.The main contents are as follows:Firstly,phenylacetylene and 2-bromopyridine were used as raw materials to synthesize a through palladium catalytic coupling reaction,and then a was oxidized by potassium permanganate to obtain asymmetric?-diketone b.Symmetric?-diketones c-d were prepared via azacarbene catalyzed directly connection of aldehydes in the presence of CO₂.All the?-diketones were characterized by nuclear magnetic resonance spectroscopy,infrared absorption spectroscopy and mass spectrometry.Next,we designed and synthesized three ferrocenyl imidazole derivatives,e-g,through carbonyl-amine condensation reaction using the synthesized?-diketone and ferrocene formaldehyde as raw materials.The three compounds were characterized by nuclear magnetic resonance spectroscopy,infrared absorption spectroscopy,mass spectrometry,and high-resolution mass spectrometry.The molecular structure of compound g was confirmed by X-ray diffraction.Finally,we used fluorescence spectroscopy,UV-Vis spectroscopy and electrochemical analysis to study the recognition performance of probes e-g towards various metal ions,and influencing factors were also studied.The fluorescence recognition performance of compound g for Al³⁺and Hg²⁺ions was given focus,so the influence of time,concentration and p H on the recognition performance of g were studied in detail to give optimize identification conditions.