The synthesis of bis(benzo-15-crown-5) derivatives and their use in potassium-PVC membrane electrodes

The Ag+ selective electrode properties of benzo-diselena selena-13-to 14-crown-4

Ion selective electrodes (ISE) for Ag+, containing 1,2-benzo-7,11-diselena-1,4-dioxacyclotridecan-2-ene (1) and (2,3-benzo-7,12-diselena-1,4-dioxacyclotetradecan-2-ene) (2) in a PVC membrane as neutral carrier, were prepared, and their selectivity coefficients for Ag+ (KpotAg,M) against other heavy metal ions, alkali and alkaline-earth metal ions, and ammonium ion were determined to show excellent Ag+ selectivities.

Copper (II) ion selective liquid membrane electrode based on new Schiff base carrier

Cu2+ selective PVC membrane electrode based on new Schiff base 2, 2'-[1,9 nonanediyl bis (nitriloethylidyne)]-bis-(1-naphthol) as a selective carrier was constructed. The electrode exhibited a linear potential response within the activity range of 1.0 x 10(-6) - 5.0 x 10(-3) moll(-1) with a Nernstian slope of 29 +/- 1 mV decade(-1) of Cu2+ activity and a limit of detection 8.0 x 10(-7) mol l(-1). The response time of the electrode was fast, 10 s, and stable potentials were obtained within the pH range of 3.5- 6.5. The potentiometric selectivity coefficients were evaluated using two solution method and revealed no important interferences except for Ag+ ion. The proposed electrode was applied as an indicator electrode to potentiometric titration of Cu2+ ions and determination of Cu2+ content in real samples such as black tea leaves and multivitamin capsule.

Molecular design of crown ethers. 19.(1) synthesis of novel disulfide- and diselenide-bridged Bis(benzo-12-crown-4)s and their Ag(+)-selective electrode properties

Two novel heteroatom-bridged bis(benzo-12-crown-4 ether)s, i.e., bis(2-nitro-4,5-(1,4,7,10-tetraoxadecamethylene)phenyl) disulfide (4) and diselenide (5), have been synthesized and characterized by elemental analysis and mass, IR, UV, and (1)H NMR spectroscopy. An X-ray crystallographic structure was obtained for 4. Ion-selective electrodes (ISE) for Ag(+), containing 4 and 5 in PVC membrane as neutral carriers, were prepared, and their selectivity coefficients for Ag(+) () were determined against other heavy metal ions, alkali and alkaline-earth metal ions, and ammonium ion using the matched potential method. These ISEs showed excellent Ag(+) selectivities, log </= -4.0, against most of the interfering cations examined, except for Hg(+) (log >/= -1.2). These values are comparable to those reported for the representative Ag(+)-selective thioethers 6 and 7, revealing that both disulfide and diselenide functionalities in 4 and 5 are equally effective Ag(+)-selective binding sites as the 1,7-dithia-4-oxa functionality in 6 and 7, irrespective of the different atom type and relative position of the sulfur/selenium donors in the ligands. Also discussed are the steric and electronic effects of the nitro groups in 4 and 5 on the Nernstian slopes obtained with the 4- and 5-based ISEs.