Synthesis Of Photosensitive Azacrown Ethers And Investigation Of Their Complexed Sensing Ability For Metal Ions

The design and synthesis of fluroscent sensor molecules based on Host-guest effect and the study of their application is becoming an important aspect of chemical research in recent years. Crown ether derivatives and the metal ions can be formed complexes by the interaction of specific Host-guest effect, which shows a high recognition of guest molecules. And when part of the compounds are a light emitting fluorescence species, that the imformation of Host-guest molecules'fluorescence signals to be output through their luminous body of the fluorescence intensity, fluorescence lifetime, fluorescence polarization, etc. After the azacrown ether containing fluorophores combined the receptor maybe have significant changes in photophysical properties, causing the optical absorption or luminescence properties changes. It can be determined by spectroscopy and sensing performance. These receptors act as a selective substrate generated light signals of molecular devices. With these photochemical sensors, we can analyze metal ions, such as for environmental protection or used to study cell signaling in biological processes.In this paper, we took 2,3-benzo-10-aza-15-crown-5 as originational reagent followed by Williamson etherification reaction, and bridged 1-naphythyloxy,5-chloro-8-quinolinoxy and coumarin groups to the originational reagent with Schotten-Baumann acylation reaction. Finally we got three photosensitive fluorescent azacrown ether compouds, namely N-bridged 1-naphythyloxybenzo-10-aza-15-crown-5,N-bridged 5-chloro -8-quinolinoxy benzo-10-aza-15-crown-5 and N-bridged coumarin-3-formyl benzo-10-aza-15-crown-5, characterized by elemental analysis and 1H-NMR spectrometry methods.By UV and fluorescence spectroscopy methods, we studied the sensing properties that created by the coordination of three photosensitive azacrown ethers and metal ions.1. The inclusion complex, which is made up of N-bridged 1-naphythyloxy -benzo-10-aza-15-crown-5 andβ-cyclodextrin,shows special UV and fluorescent sensitivity on Na⁺,K⁺ and Mg²⁺ ions, while there is no spctrum changes in identification sensor for Ca²⁺ and tetrabutylammonium cations.2. N-bridged 5-chloro-8-quinolinoxy benzo-10-aza-15-crown-5 has a special sensitivity on the transition metal ions. For instance, Co²⁺,Ni²⁺ and Cu²⁺ions strongly quenched the host's fluorescent intensity, as well as Mn²⁺ ion. However, Cd²⁺ and Hg²⁺ ions could enhance the fluorescent intensity. Experiments show that the azacrown ether was found to no obvious sensibility alkali metal, alkaline earth metal ions, so the choice of recognition of sensor performance is significant.3. The sensing properties of N-bridged coumarin-3-formyl benzo-10-aza -15-crown-5 to transiton metal ions also has been determined. As a result, the fluorescence of main compound has been strongly quenched by Cu²⁺,Cd²⁺ and Hg²⁺ ions, while Co²⁺ and Ni²⁺ ions were only a weak effect on the azacrown ether's fluorescence intensity. In this experiment, we also tested the impact of alkali metal and alkaline earth metal ions, but we didn't find significant response.