Design, Synthesis And Property Studies Of Functionalized Crown Ethers

Crown ethers are a kind of macrocyclic polyethers prepared artificially. Design, synthesis of crown compounds as well as the selective binding between crown compounds and metal ions have been one of the hot topics in the research field of supermolecular chemistry and host-guest chemistry. Fluorescence probe detection method is simple and with high sensitivity, good selectivity as well as short response time. Thanks to the good complex capacities of crown ethers for metal ions, the advantages of crown ether fluorescent probes are more apparent and their application in the field of medicine and environment monitoring is more and more extensive.This paper mainly synthesize some new type functionalized crown ethers, their UV and fluorescence spectrum were studied in order to identify some desirable receptors which show high selectivity to a specific ion. The paper is devided into the following parts.In the first part, the synthetic way of aroylthiourea crown ethers was discussed and their optical properties were further studied. It was found that this kind of receptor could recognize not only cations such as copper, cobaltic and ferric ions, but also anions such as fluorion and acetate. In the process of anion recognition, electronic effect would influence the recognition to a certain extent.In the second part, a new type fluorescence ionophore based on dibenzo-24-crown-8, of which benzothiazole acts as fluorophore was synthesized. Complexation of this receptor (cis-dibenzothiazolyldibenzo-24-crown-8) with alkali metal ions leads to intramolecular charge transfer and results in the change of UV-Vis absorption spectrum and fluorescence spectrum. Among all alkali metal ions, cesium ion is most effective. Trifluoroacetic acid can cause redshift of UV-Vis absorption spectra and great enhancement of the fluorescent intensity at 433 nm owing to the effect of protonation. In the third part, a series of single-armed and double-armed lariat crown ethers containing aminoanthraquinone or aminopyrene as fluorophore were synthesized via acelation and Michael addition reaction, the reactions metioned above have advantages such as mild conditions, safe and convenient operation. The lariat crown ethers synthesized all have the ability to recognize silver, copper and ferric ions; while lariat crown ethers containing aminopyrene as fluorophore can also recognize lead ion.