bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sandwich and Half‐Sandwich (Imido)niobium Complexes
Authors: Antiñolo Antonio , Fajardo Mariano , Otero Antonio , Prashar Sanjiv 
Published: December 2002

AbstractThis review discusses the study we have carried out towards the synthesis, structure and reactivity of (imido)niobium complexes, which contain at least one cyclopentadienyl ligand. The following families of niobium complexes are described: (i) half‐sandwich imido complexes; (ii) metallocene imido compounds; (iii) imido complexes containing ansa‐cyclopentadienyl ligands; (iv) dinuclear imido complexes such as [{Nb(η5‐C5H4SiMe3)2Cl}2(μ‐1,3‐N2C6H4)]. In addition we describe spectroscopic and structural features of the (imido)niobium complexes. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)
Selective Insertion of Dioxygen into an (η2‐C60)−Ir Bond: Synthesis and Structure of the First Metallacyclic Complex with a σ‐Coordinated Fullerene Molecule
Authors: Usatov Alexander V. , Martynova Ekaterina V. , Dolgushin Fedor M. , Peregudov Alexander S. , Antipin Mikhail Yu. , Novikov Yurii N. 
Published: December 2002

AbstractOxidation of the carboranyliridium fullerene complex [(η2‐C60)Ir(o‐HCB10H9CCH2PPh2‐B,P)(tBuNC)2] (I) in CHCl3 solution by O2 occurs by a selective insertion of the dioxygen molecule into the longest Ir−C bond (in the trans‐position relative to the B‐σ‐carboranyl fragment) to give a new metal complex [σ‐C60OO‐Ir(o‐HCB10H9CCH2PPh2‐B,P)(tBuNC)2] (II). Complex II was isolated and characterized analytically and by UV, IR, 1H and 31P NMR spectroscopy. An X‐ray diffraction study of II showed that this complex contains a cyclic iridaperoxide fragment in which the fullerene cage is σ‐coordinated to the iridium atom. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Self‐Assembly of a One‐Dimensional Silver Complex Containing Two Kinds of Helical Chains
Authors: Sun Daofeng , Cao Rong , Sun Yanqiong , Bi Wenhua , Li Xing , Hong Maochun , Zhao Yingjun 
Published: December 2002

AbstractSelf‐assembly of the potassium sulfonate salt K2pesp [H2pesp = piperazine‐1,4‐bis(2‐ethanesulfonic acid] with piperazine (PIP) and a silver(I) salt in solution allows the preparation of a novel one‐dimensional helical polymer [Ag(PIP)]n·[Ag(pesd)]n·2nH2O (1), which is made up of two independent silver‐containing helical chains, namely [Ag(PIP)]n and [Ag(pesd)]n. There is no direct bonding interaction between the two chains, and the hydrogen bonds between the chains give 1 a two‐dimensional layer supramolecular architecture. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Unprecedented Change of the Jahn−Teller Axis in a Centrosymmetric CuII Complex Induced by Lattice Water Molecules − Crystal and Molecular Structures of Bis[bis(3,5‐dimethylpyrazol‐1‐yl)acetato]copper(II) and Its Dihydrate
Authors: Kozlevčar Bojan , Gamez Patrick , de Gelder René , Driessen Willem L. , Reedijk Jan 
Published: December 2002

AbstractTwo copper coordination compounds with the tridentate (NON) ligand bis(3,5‐dimethylpyrazol‐1‐yl)acetic acid (Hbdmpza) are reported. The central coordination sphere in both compounds is fulfilled by two ligands in [CuL2]. The ligands are centrosymmetrically oriented around the copper ion, thus forming a trans‐CuN4O2 elongated octahedral chromophore. The atoms in both compounds are not positioned at the same places in the Jahn−Teller‐distorted octahedral environment. For compound [CuL2] (1) two nitrogen atoms are located on the longer axis [Cu−N: 2.438(2) Å], while the other two nitrogen atoms [Cu−N: 2.006(2) Å] and the two oxygen atoms [Cu−O: 1.983(2) Å] form the basal plane of the octahedron. The coordination sphere for [CuL2]·2H2O (2) is composed of four nitrogen atoms [Cu−N: 2.013(3), 2.038(2) Å] that form the basal plane, while the two oxygen atoms are at a longer distance [Cu−O: 2.293(2) Å]. The water molecules in 2 are hydrogen bonded to the non‐coordinated carboxylate oxygen atoms, forming bridges between two neighbouring monomeric units and leading to an infinite chain. Significant differences are observed for both compounds by spectroscopic investigations (EPR, IR, ligand field). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The Unexpected Formation of a Novel Fluorinated Triene
Authors: Shevchenko Igor , Andrushko Vasyl , Lork Enno , Röschenthaler Gerd‐Volker 
Published: December 2002

AbstractBis[bis(dialkylamino)phosphanyl]methane (1) and 4,4,4‐trifluoro‐3‐(trifluoromethyl)‐2‐butenenitrile (2) unexpectedly gave triene 3. According to the X‐ray structure analysis compound 3 exists in the solid state exclusively as one isomer. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Unique Magnetic Behavior in a One‐Dimensional Coordination Polymer [Co(tmpyim)2(tp)]
Authors: Li Licun , Liu Zhiliang , Turner Scott S. , Liao Daizheng , Jiang Zonghui , Yan Shiping 
Published: December 2002

AbstractA one dimensional cobalt(II)−radical complex [Co(tmpyim)2(tp)] [tmpyim = 4,4,5,5‐tetramethyl‐2‐(3′‐pyridyl)imidazoline‐1‐oxyl 3‐oxide and tp = terephthalate dianion] has been synthesized and characterized by X‐ray crystallography. The crystal structure consists of infinite chains of Co(tmpyim)2 units cross‐linked by terephthalate ligands. The magnetic behavior of the complex is unique and is discussed in connection with the crystal structure. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
The Structure of Some Amine Solvates of Magnesium Bis(tetrahydroborate) and DFT Calculations on Solvates of Lithium Tetrahydroborate
Authors: Bremer Mathias , Nöth Heinrich , Warchhold Marcus 
Published: December 2002

AbstractEight solvates of magnesium bis(tetrahydroborate) have been prepared and characterised by NMR and IR spectroscopy, and five of them also by X‐ray crystallography. Compounds Mg(BH4)2·3NH2tBu and Mg(BH4)2·3pip each have a distorted trigonal‐bipyramidal structure (with the BH4 group viewed as a simple ligand) while the putative Mg(BH4)2·6py proved to be [Mg(BH4)2·4py] with a pseudooctahedral structure, two py molecules being present as solvent of crystallization. Similarly, Mg(BH4)2·8DMSO contains the cation [Mg(DMSO)6]2+ in the crystal, and Mg(BH4)2·6NH2Bzl has an ionic lattice made up of Mg(NH2Bzl)62+ and BH4− ions. The BH4 groups in the molecular compounds are bonded to the Mg centre through double hydrogen bonds. In order to study the bonding in alkali and alkali earth metal tetrahydroborates, DFT calculations were performed for LiBH4 and its ammonia and dimethyl ether solvates. The minimum‐energy structure for a LiBH4 molecule has C3v symmetry; this is not changed when one ammonia molecule is added and is also the result for LiBH4·3NH3. Addition of the first NH3 or Me2O molecule contributes more to the stabilisation than a second or a third molecule. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Coordination Modes of 9‐Methyladenine in cis‐Platinum(II) Complexes with Dimethyl(phenyl)phosphanes as Ancillary Ligands − Synthesis and Characterization of cis‐[PtL2(9‐MeAd)2](NO3)2, cis‐[PtL2{9‐MeAd(−H)}]3(NO3)3, and cis‐[L2Pt{9‐MeAd(−H)}PtL2](NO3)3
Authors: Longato Bruno , Pasquato Lucia , Mucci Adele , Schenetti Luisa 
Published: December 2002

AbstractTreatment of 9‐methyladenine (9‐MeAd) with cis‐[PtL2(NO3)2] (1) (L = PMe2Ph) in a 2:1 molar ratio generated the bis(adduct) cis‐[PtL2(9‐MeAd)2](NO3)2 (2), which was isolated and fully characterized by multinuclear (1H, 31P, 13C, 195Pt and 15N) NMR analysis, which showed that the two nucleobases are selectively coordinated through the N1 atom. Small amounts of a mono(adduct) cis‐[PtL2(S)(9‐MeAd)]2+ (3) (S = solvent) and of a diplatinated species cis‐[L2Pt(S){9‐MeAd(−H)}PtL2]3+ (4) are formed in DMSO solution when 9‐MeAd is present in smaller quantities than 1. Complex 3 is platinated at N1, with a solvent molecule representing the fourth ligand around the metal center. Complex 4 contains an adenine molecule deprotonated and platinated at N1,N6,N7, with two cis‐L2Pt units bonded to nitrogen atom N1 and to nitrogen atoms N6 and N7, respectively. With increasing relative concentration of the nucleobase, both complexes 3 and 4 progressively convert into the bis(adduct) 2, the only species detectable in solution when the Ad/Pt molar ratio is 2:1. The trinuclear compound cis‐[L2Pt{9‐MeAd(−H)}]3(NO3)3 (5) (L = PMe2Ph), containing an NH2‐deprotonated nucleobase bridging the metal centers through the N1 and N6 atoms, is quantitatively formed when the dinuclear hydroxo complex cis‐[Pt(μ‐OH)L2]2(NO3)2 (6) reacts with 9‐MeAd in CH3CN solution. The isolated complex was fully characterized by multinuclear NMR spectroscopy and mass spectrometry. It appears to be stable in solution in CH3CN and chlorinated solvents, whereas in DMSO it partially converts into a new species, probably the dinuclear analog cis‐[PtL2{9‐MeAd(−H)}]2(NO3)2, in which the adenine maintains its coordination mode. At equilibrium the trinuclear/dinuclear species molar ratio is 20:1. Through the addition of a stoichiometric amount of nitrate 1 to a DMSO solution of 5 we were able to generate the diplatinated compound 4 in high yield. Complex 4 displays a new coordination mode for the adeninate ion, with N1 bonded to one platinum atom whereas N6 and N7 are chelated to a second one. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Chelation versus Cyclometalation in a Cationic Dppn−RhI Complex − A Unique Rearrangement of Norbornadiene via C−H Activation of the Pyridazine Ring
Authors: Dorta Reto , Konstantinovski Leonid , Shimon Linda J. W. , Ben‐David Yehoshoa , Milstein David 
Published: December 2002

AbstractThe tetradentate ligand 3,6‐bis(2‐pyridyl)pyridazine (dppn) was treated with cationic RhI precursors. The mononuclear complexes [Rh(dppn)(NBD)]BF4 (1) and [Rh(dppn)(COD)]BF4 (5) were obtained in quantitative yield when treating dppn with [Rh(NBD)2]BF4 or [Rh(COD)2]BF4 respectively. Treatment of 1 with a second equivalent of the metal precursor [Rh(NBD)(CH3CN)2]BF4 led to the dinuclear complex [Rh2(dppn‐H)(NBD)(η1‐C7H9)(CH3CN)2](BF4)2 (2) [dppn‐H = μ‐C4HN2(C5H4N)2‐3,6], a mixed RhI−RhIII complex. This complex arises from C−H activation of the pyridazine ring, followed by a unique rearrangement of the NBD ligand. Compound 2 was also obtained directly by treating dppn with 2 equiv. of [Rh(NBD)(CH3CN)2]BF4. The complex [Rh2(dppn‐H)(NBD)(η1‐C7H9)(CH3OH)2(CH3CN)](BF4)2 (4) was obtained by dissolving 2 in methanol. Full characterization of compounds 1, 4 and 5 included an investigation by 1H‐15N GHMBC NMR spectroscopy and single‐crystal X‐ray structures of 1 and 4. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)
The Ambivalent Bonding of the 3(5)‐Isopropylpyrazolyl Moiety in Homo‐ and Heteroscorpionate Hydrobis(3‐R1‐5‐R2‐pyrazolyl)(y‐isopropylpyrazolyl)boratocobalt(II) Complexes (y = 3 or 5)
Authors: Ruman Tomasz , Ciunik Zbigniew , Wołowiec Stanisław 
Published: December 2002

AbstractThe synthesis of hydrotris(pyrazol‐1‐yl)borate ligands (Tpx) by condensation of sodium borohydride with 3(5)‐isopropylpyrazole and either 5(3)‐methyl‐3(5)‐phenylpyrazole or 3,5‐diphenylpyrazole gave the novel heteroscorpionate ligands hydrobis(5‐methyl‐3‐phenylpyrazolyl)(5‐isopropylpyrazolyl)borate and hydrobis(3,5‐diphenylpyrazolyl)(5‐isopropylpyrazolyl)borate, respectively. These were converted into CoTpx(NCS) complexes as well as CoTpx2 in the case of the former ligand. In an attempted synthesis of heteroscorpionates bearing two y‐isopropylpyrazolyl moieties (y = 3 or 5) formation of the homoscorpionate hydrotris(3‐isopropylpyrazolyl)borate along with the above‐mentioned heteroscorpionates was noticed; no formation of the desired heteroscorpionates could be detected. The bis[hydrobis(5‐methyl‐3‐phenylpyrazolyl)(5‐isopropylpyrazolyl)borato]cobalt(II) and tetrahydrofuranothiocyanatobis[hydrobis(5‐methyl‐3phenylpyrazolyl)(5‐isopropylpyrazolyl)borato]cobalt(II) tetrahydrofuran solvate complexes were studied by X‐ray crystallography. Two Tpx ligands provide six nitrogen donors from pyrazol‐1‐yl residues to form a Tpx2Co complex in which two 5‐isopropylpyrazolyl rings are placed in a plane of symmetry, whereas the same Tpx ligand is bound in an η3 fashion in the pentacoordinate [CoTpx(NCS)(THF)]·THF complex, in which a nitrogen atom from thiocyanate and an oxygen atom from THF complete the coordination sphere of the central metal ion. These compounds as well as the complexes thiocyanatohydrobis(3,5‐diphenylpyrazolyl)(5‐isopropylpyrazolyl)boratocobalt(II) and thiocyanatohydrotris(3‐isopropylpyrazolyl)boratocobalt(II) were characterized by 1H NMR and IR spectroscopy. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)
Two New Zeolite‐Like Supramolecular Copper Complexes
Authors: Sun Daofeng , Cao Rong , Sun Yanqiong , Li Xing , Bi Wenhua , Hong Maochun , Zhao Yingjun 
Published: December 2002

AbstractAssembly of sodium 5‐sulfoisophthalate (NaH2SIPA) with copper(II) nitrate in the presence of an amine results in the formation of two new types of supramolecular copper complexes [{Cu(H2O)2(HSIPA)}·2H2O·(PIP)1/2]n (1) and [{Cu(H2O)3(HSIPA)}·6H2O·(hmt)1/2]n (2). Both complexes have 1D zigzag chain structures formed by the interconnection of four‐ or five‐coordinate copper ions by carboxylate ligands. The 3D supramolecular architectures are dependent on the guest amine. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Tripodal Phosphane Ligands with Novel Linker Units and Their Rhodium Complexes as Building Blocks for Dendrimer Catalysts
Authors: Findeis Ralf A. , Gade Lutz H. 
Published: December 2002

AbstractAn efficient strategy for the backbone functionalization of a tripodal phosphane ligand which allows its attachment to solid supports and polymers has been developed. Using pentaerythrol (1) as the starting material, the functionalized phosphane tripod HOCH2CH2OCH2C(CH2PPh2)3 (9) was obtained in good yield in a four‐step synthesis. Reaction of 9 with [Mo(CO)3(MeCN)3] and [Rh(COD)2][A] gave the complexes [{HOCH2CH2OCH2C(CH2PPh2)3}Mo(CO)3] (10) and [{HOCH2CH2OCH2C(CH2PPh2)3}Rh(COD)][A] (A = BF4: 11a, PF6: 11b), respectively, two of which were characterised by X‐ray diffraction. The carbosilane dendrimer Si{(CH2)3SiMe2Cl}4 “G[0]‐[Cl]4” (12) and its first generation analogue Si[(CH2)3SiMe{(CH2)3SiMe2Cl}2]4 “G[1]‐[Cl]8” (15) were reacted with, respectively, four and eight molar equivalents of the lithium alkoxy derivative of 9 giving the two functionalized dendrimers G[0]‐[OCH2CH2Otriphos]4 (13) and G[1]‐[OCH2CH2Otriphos]8 (16). These were metallated with four and eight molar equivalents of [Rh(COD)2][BF4] in CH2Cl2, selectively yielding the metallated dendrimers G[0][OCH2CH2OtriphosRh(COD)BF4]4 (14) and G[1]‐[OCH2CH2OtriphosRh(COD)BF4]8 (17). Comparative catalytic hydrogenation of styrene and 1‐hexene using [Rh(triphos)(COD)][BF4] (11a) and the metallodendrimers 14 and 17 showed that the fixation to the low generation dendrimers did not alter the catalytic hydrogenation properties of the catalysts. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Triorganotin Fluoride Structures: A Ligand Close‐Packing Model with Predominantly Ionic Sn−F Bonds
Authors: Beckmann Jens , Horn Dagmar , Jurkschat Klaus , Rosche Fred , Schürmann Markus , Zachwieja Uwe , Dakternieks Dainis , Duthie Andrew , Lim Allan E. K. 
Published: December 2002

AbstractThe synthesis and complete characterization by multinuclear NMR, infrared, and Mössbauer spectroscopy, by single crystal X‐ray analysis, as well as by electrospray mass spectrometry of the new soluble triorganotin fluoride Me2PhSnF (1) is reported. The crystal structure of 1 reveals a rod‐like polymeric structure in the solid state. Solutions of 1 in apolar solvents, such as toluene, contain mixtures of interconvertible oligomers. Ab initio MO calculations on model compounds H3SnF, [H3SnFSnH3]+, and [FH3SnFSnH3F]− indicate that the Sn−F bonds are substantially ionic in character, and suggest open‐chain species, rather than cyclic species. In donor solvents, such as pyridine, 1 forms complexes with the solvent, such as Me2PhSnF·pyridine. The solid‐state structure of (Me3SiCH2)3SnF (2) is reformulated as monomeric with a weak intermolecular Sn···F interaction that gives rise to a [4+1] coordination. The relative short Sn−Sn separation enables the fluorine atoms to oscillate (flip‐flop) between two neighboring (Me3SiCH2)3Sn− groups, which is expressed in the X‐ray experiment by a dynamic disorder. Ab initio MO calculations on a model compound, [H3SnFSnH3]+, suggest only a small energy barrier for the flip‐flop motion. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2003)
Cover Picture
Authors: Dorta Reto , Konstantinovski Leonid , Shimon Linda J. W. , Ben‐David Yehoshoa , Milstein David 
Published: December 2002

AbstractThe cover picture shows the structure of an unusual dinuclear RhI−RhIII complex obtained in the reaction of the tetradentate ligand 3,6‐bis(2‐pyridyl)pyridazine with cationic (diene)RhI precursors. Initially, the expected N,N‐bidentate RhI complex is formed, which upon further reaction with the RhI precursor undergoes C−H bond activation of the pyridazine ring, forming a C,N‐bidentate RhIII center. This is followed by a unique rearrangement of the diene, which is dependent on the metal precursor and on the ligand used. Details are discussed in the article by D. Milstein et al. on p. 70 ff. We thank Relli Mahager (Graphics Department, WIS) for producing the colour picture.
Electrochemical Sensors Based on Carbon Nanotubes
Authors: Zhao Qiang , Gan Zhenhai , Zhuang Qiankun 
Published: December 2002

AbstractCarbon nanotubes are attractive new materials. It has been about a decade since carbon nanotubes were discovered. Carbon nanotubes have many outstanding properties and have many practical or potential applications. In this short review we introduce recent advances in carbon nanotubes as potential material for electrochemical sensors. The advantages of carbon nanotubes as sensors are discussed along with future prospects.
Batch Injection Analysis Utilizing Modified Electrodes with Tetraruthenated Porphyrin Films for Acetaminophen Quantification
Authors: Quintino Maria S. M. , Araki Koiti , Toma Henrique E. , Angnes Lúcio 
Published: December 2002

AbstractBatch injection analysis (BIA) utilizing amperometric detection with glassy carbon electrodes modified with [Co(TPyP){Ru(bipy)2Cl}4](TFMS)5⋅H2O porphyrin films were explored for acetaminophen analysis in pharmaceutical formulations. BIA is an interesting alternative for application of electrodes modified with tetraruthenated porphyrins. This sensor exhibited sharp current response peaks, rapid washout and excellent reproducibility for BIA‐amperometric quantification of acetaminophen. Also, a wide linear working range (10−4 to 10−6 mol L−1) as well as high sensitivity and sampling frequency rate (detection limit=1.1×10−7 mol L−1, sampling frequency=120 injections/h) and a small volume of analysis (100 μL/injection) was achieved. Furthermore, the proposed method permits the direct quantification of acetaminophen in many pharmaceutical products, avoiding cumbersome processes as previous separations, solvent extraction or sample filtration. The new procedure was applied to the analysis of commercial pharmaceutical products and the results were in excellent agreement with the ones obtained by spectrophotometric method. Accordingly, this amperometric method showed to be very well suited for quality control analysis and other applications with similar requirements.
Electrochemical Studies for the Interaction of DNA with an Irreversible Redox Compound – Hoechst 33258
Authors: Sufen Wang , Tuzhi Peng , Yang Catherine F. 
Published: December 2002

AbstractAn electrochemical equation suitable for examining the interaction of irreversible redox compounds with DNA is established. According to the equation, diffusion coefficients of both free and binding compounds (Df , Db), binding constant (K) and binding site size (s) of compounds with DNA could be obtained simultaneously by nonlinear fit analysis of electrochemical data. Bis‐benzimidazole derivative (Hoechst 33258), as an irreversible redox compound, was investigated for its electrochemical behavior and the interaction with natural fish sperm DNA (fsDNA) using cyclic voltammetry, chronocoulometry, bulk electrolysis and scanning electrochemical microscope technique. A nonlinear fit analysis of the experimental data yielded: Df=8.3×10−5 cm2 s−1, Db=6.0×10−6 cm2 s−1, K=2.1×108 cm3 mol−1, s=3.9. The overall results suggest that Hoechst 33258 binds tightly to the minor groove of fsDNA and covers four base pairs.
Mixed Aza‐Thioether Crowns Containing a 1,10‐Phenanthroline Sub‐Unit as Neutral Ionophores for Silver Ion
Authors: Shamsipur Mojtaba , Javanbakht Mehran , Ganjali Mohammad Reza , Mousavi Mir Fazlollah , Lippolis Vito , Garau Alessandra 
Published: December 2002

AbstractThree different recently synthesized aza‐thioether crowns containing a 1,10‐phenanthroline sub‐unit (L1–L3) and a corresponding acyclic ligand (L4) were studied to characterize their abilities as silver ion ionophores in PVC‐membrane electrodes. Novel conventional silver‐selective electrodes with internal reference solution (CONISE) and coated graphite‐solid contact electrodes (SCISE) were prepared based on one of the 15‐membered crowns containing two donating S atoms and two phenanthroline‐N atoms (L1). The electrodes reveal a Nernstian behavior over wide Ag+ ion concentration ranges (1.0×10−5−1.0×10−1 M for CONISE and 5.0×10−8−4.0×10−2 M for SCISE) and very low limits of detection (8.0×10−6 M for CONISE and 3.0×10−8 M for SCISE). The potentiometric response is independent from pH of the solution in the pH range 3.0–8.0. The electrodes manifest advantages of low resistance, very fast response and, most importantly, good selectivities relative to a wide variety of other cations. The electrodes can be used for at least 2 months (for CONISE) and 4 months for (SCISE) without any appreciable divergence in potentials. The electrodes were used as an indicator electrode in the potentiometric titration of Ag+ ion and in the determination of silver in photographic emulsions and in radiographic and photographic films.
Electrochemical Behavior of Some Thiotriazoles in Aqueous‐Alcoholic Media at GCE
Authors: Fotouhi Lida , Hajilari Fatemeh , Heravi Majid M. 
Published: December 2002

AbstractAn electrochemical study related to the electrooxidation of 4‐amino‐3‐thio‐5‐methyl‐1,2,4‐triazole (I), 4‐amino‐3‐thio‐5‐phenyl‐1,2,4‐triazole (II) and 3‐thio‐5‐phenyl‐1,2,4‐triazole (III), in 10% v/v methanol‐acetate buffer pH 4.6 has been performed. A variety of electrochemical techniques such as differential pulse voltammetry, cyclic voltammetry, double‐potential step chronoamperometry, rotating‐disk electrode voltammetry and coulometry, were employed to clarify that the mechanism of the electrode process follows the oxidation of thiol compounds. All the compounds exhibit similar redox behavior under the given conditions. They display one irreversible oxidation peak, which is diffusion controlled. From the plot of current function in cyclic voltammetry and the ratio of ic/ia less than one in double‐potential step chronoamperometry, it was established that these compounds undergo an one electron oxidation followed by a dimerization process involving the formation of disulfide derivative (EC mechanism). The pKa values were obtained by the dependence of limiting current and potential with in the wide pH interval. The transfer coefficients, the diffusion coefficients and rate constant of coupled chemical reaction were also reported. The substituent effects were also investigated.