Abstract: Six of two types ferrocenylpolythia crown ethers(1-6)were prepared by reacting 1,1′-bis(hydroxymethyl)ferrocene or ferrocenccarboxyaldehyde with α,ω-dimercaptan compounds ingood yield.A serics of Ag-ion-selective electrodes based on the crown ethers(2-6)as elec-troactive material were prepared. The electrode with 4 was found to have the best properties.It shows linear response of 1×10^-1-3×10^-5mol/L AgNO₃ and potentiometric selectivity co-efficients of 10^-3and 10^-4-10^-5for cations of Ⅰand Ⅱ valency respeetively. The selecti-vities of the electrodes for Na⁺,Hg²⁺, Mg²⁺ were 44-682 times better than other crownether electrodes reported in literature.

Key words: ferrocenylthia crown ether, synthesis, ion-selective electrode