Mercury(II) and silver(I) ion-selective electrodes based on dithia crown ethers

Abstract

Republic of ChinaMercury (Hg2+) and silver (Ag+) ion-selective PVC membrane electrodes based on 1,4-dithia-I 2-crown-4 and 1,4-dithia-l5-crown-5 as neutral carriers were successfully developed. Both electrodes exhibited good linear responses of 30 and 40 mV decade-1 for Hg2+ and Ag+/ respectively, within the concentration ranges 10-2-10-6 M Hg(N03)2 and 10-1-10-6 M AgN03. Some other crown ethers and cryptands were also investigated as neutral carriers for both ions. Both the mercury and silver electrodes exhibited comparatively good selectivities for mercury(l1) and silvertl) ions in comparison with alkali metal, alkaline earth metal and some heavy metal ions. These crown ether ion-selective electrodes are suitable for use with aqueous solutions at pH 3 2. They were applied as sensors in titrations of Br-and CIwith Ag+ and of Hg2+ with 1-and Cr2072-and in the determination of the solubility products of AgCl in aqueous solutions.

Discrimination of Methylammonium from Organic Ammonium Ions Using Ion-Selective Electrodes Based on Calix[4]arene-crown-6 Conjugates

“…Similar observations of crown ethers losing their metal-binding capacity due to protonation have been reported previously. [18][19][20] These results demonstrated that the combination of calix [4]-bis-2,3-naphtho-crown-6 and bis(2-ethylhexyl) sebacate provided new electrode materials for discriminating between methylammonium and various other organic ammonium ions. The materials were, however, less selective for inorganic cations.…”

Novel potentiometric and optical silver ion-selective sensors with subnanomolar detection limits

“…This might be because, in contrast to the other calix [4]arene derivatives, it does not have a cone conformation [43]. 1 H NMR measurements performed in CDCl 3 with ligand IV in the presence of Ag + revealed that the two allyl groups in 1,3-alt conformation are not sufficient for binding, probably because the adjacent phenyl rings are not arranged in parallel position due to steric hindrance of the bulky tert-butyl groups, so that they cannot stabilize Ag + by additional π-cation interaction. At the same time, upon complexation, a conformational change to paco (partial cone) has been observed affording three allyl groups in syn position capable of efficient Ag + binding as reflected by the significant downfield shifts of the CH 2 =CH protons [43].…”

“…Since the description of the first Ag + -selective ionophore in 1986 [1], at least 50 different lipophilic ligands have been applied in Ag + -selective membranes (earlier contributions are covered in [2,3]; for a selection of more recent papers, see [4][5][6][7][8][9][10][11][12][13][14][15][16]{Johnson, 2002 #21}{Kim, 2005 #56}{Zhang, 2006 #55}). In spite of this large number of compounds, there is an ongoing interest in developing highly selective lipophilic complexing agents for Ag + [13][14][15][17][18][19].…”

Potentiometric Performance of Silver Ion-Selective Electrodes Based on Tridentate Schiff Base Derivatives

“…6,7 We found that the synthesized Schiff bases could coordinate with a silver-ion though the two nitrogen atoms in a diagonal line, and show excellent silver ion selectivity, which is comparable to those of acyclic oligoether, polythiacrown eters and acyclic polythia compounds. [8][9][10][11][12][13] However, for pursuing the practicability of a silver ionophore of N,N′-bis(2′-hydroxyimino-1′-phenylpropyleden)-1,3-propanediamine (PHO3), 6 which is most promising in Schiff bases, the following have remained: control of the hydrolysis of PHO3 in a poly(vinyl chloride) (PVC) membrane, and an improvement in the silver ion selectivity. It was proven that the introduction of a substituent with lipophilicity, such as a butyl group, to the side chain of PHO3 was effective to control the hydrolysis in a PVC membrane.…”