Consuelo Pérez-Jiménez

Silver-selective membrane electrodes using acyclic dithia benzene derivative neutral carriers. Comparison with related macrocyclic compounds

Abstract Four new acyclic dithia benzene derivatives have been synthesized: 1,3-bis[(ethylthio)methyl]benzene; 1,3-bis-[(pentylthio)methyl]benzene; 1,3-bis[(octylthio)methyl]benzene, 1,3-bis[(dodecylthio)methyl]benzene. All compounds have been tested as silver(I) ion sensors in membrane-based ion-selective electrodes, exhibiting good sensitivity, detection limits, reproducibility and selectivity. The chemical recognition of silver(I) by these receptors is compared to the behaviour presented by closely related macrocyclic and acyclic polythia compounds.

Application of a new phosphadithiamacrocycle to ClO−4-selective CHEMFET and ion-selective electrode devices

Abstract A new dithiamacrocycle incorporating a phosphine donor group (I) has been synthesized and tested as neutral carrier in PVC membranes. ClO−4-selective CHEMFET and ISE devices based on these plasticized membranes have been developed. Both devices have shown Nernstian response and a wide working pH range. Most common anions, except BF−4, do not cause interferences. The response properties and selectivity found for perchlorate ions compare favourably with the commercial and conventional ClO−4 electrodes based on quaternary ammonium ion-exchange sites. This is probably the first example of perchlorate selective CHEMFETs.

Silver(I) ion-selective electrodes based on polythiamacrocycles

Some polythiamacrocycles having aromatic rings as macrocyclic components have been synthesised and tested as sensors in solid-state electrodes. High selectivity for Ag+, even over that for Hg2+, and excellent electrode properties have been found.

Perchlorate-selective MEMFETs and ISEs based on a new phosphadithiamacrocycle

Abstract A new phosphadithiamacrocycle has been synthesized and used as neutral carrier in ion-selective PVC membranes. These membranes have been applied to the development of perchlorate-selective MEMFETs and ISEs. Both devices have shown Nernstian response and a wide working pH range. The response and selectivity found for perchlorate ions is better than those of conventional Cl O 4 − electrodes based on hydrophobic cations as electroactive species.

A new pyridine-based phosphorus-containing macrocycle. Crystal structure of [Co(Lox)2][CoCl3(Lox)]2 (Lox=6-phenyl-6-oxo-15-aza-6-phospha-3,9-dithiabicyclo [9,3,1]pentadeca-1 (15), 11, 13-triene)

Abstract A new pyridine-based macrocycle 6-phenyl-15-6-phospa-3,9-dithiabicyclol[9,3,1]pentadeca-1(15),11,13-triene (L), containing the NS2P donor set, was prepared and characterised. The reaction of L with CoCl2 in acetonitrile yielded the double complex salt [Co(Lox)2][CoCl3(Lox)]2 where the phosphine groups of the ligands L are in the phosphine-oxide form (Lox). The single crystal structue of the complex was determined by X-ray diffraction methods. Crystal data: triclinic, space group P-1 (No.2), a = 11.634(1), b = 19.251(2), c = 9.497(1) A , α = 93.65(1), β = 109.711(9), γ = 95.12(1)°, U = 1984.4(4) A 3 , Z = 1 . In each [CoCl3(Lox)]− anion the Co(II) atoms is in a slightly distorted tetrahedral environment define by three chlorine atoms and the phosphine-oxide oyxygen atom of one Lox ligand, whereas in the [Co(Lox)2]2+ cation the Co(II) atom lies in a distroted octahedral environment of two pyridine nitrogen atoms, two thioethersulfur complex was investigated. atoms and two phosphinc-oxide oxygen atoms provided by two facially coordinating Lox ligands. The magnetic behaviour of the

Coordination of silver(I) at the surface of carbon paste electrodes modified with 2,5,8-trithia[9]-m-cyclophane as studied by cyclic voltammetry

Abstract The electrochemical behaviour of silver(I) at carbon paste electrodes (CPE) modified by 2,5,8-trithia[9]- m -cyclophane (TTCP) were studied voltammetrically in aqueous solutions of sodium perchlorate. Up to three cathodic peaks and anodic currents were observed in the cyclic voltammograms at the modified CPE, in contrast to the voltammograms of Ag + at the unmodified CPE in the presence and in the absence of TTCP in the solution. In the voltammograms high cathodic currents are contrasted by low anodic currents, e.g. in the case of 1×10 −5 M or 2×10 −5 M Ag + cathodic currents in are the range from 10 to 30 μA, whereas anodic currents are lower than 2 μA. The electrode reactions of silver at the modified electrode are discussed. The peak potential and peak currents of the cathodic currents depend strongly on the preceding cycle. The appearance of two cathodic peaks is attributed to oxidative formation of surface complexes of Ag(I) at positive potentials after preceding cathodisation with deposition of Ag(0). The reduction potential and consequently the stability of the complexes formed depended on the upper reversal potential. Furthermore, the influence of potentiostatic pretreatment and pretreatment at open circuit is studied. After pretreatment at open circuit a cathodic peak with time-dependent peak current appeared in the second scan to negative potentials.