Redox-adaptable copper hosts. Pyridazine-linked cryptands accommodate copper in a range of redox States

A series of structurally characterized copper complexes of two pyridazine-spaced cryptands in redox states + (I,I), (II,I), (II), (II,II) are reported. The hexaimine cryptand L(I) [formed by the 2 + 3 condensation of 3,6-diformylpyridazine with tris(2-aminoethyl)amine (tren)] is able to accommodate two non-stereochemically demanding copper(I) ions, resulting in [Cu(I)(2)L(I)](BF(4))(2) 1, or one stereochemically demanding copper(II) ion, resulting in [Cu(II)L(I)()](BF(4))(2) 3. Complex 3 crystallizes in two forms, 3a and 3b, with differing copper(II) ion coordination geometries. Addition of copper(I) to the monometallic complex 3 results in the mixed-valence complex [Cu(I)Cu(II)L(I)](X)(3) (X = PF(6)(-), 2a; X = BF(4)(-), 2b) which is well stabilized within this cryptand as indicated by electrochemical studies (K(com) = 2.1 x 10(11)). The structurally characterized, octaamine cryptand L(A), prepared by sodium borohydride reduction of L(I), is more flexible than L(I) and can accommodate two stereochemically demanding copper(II) ions, generating the dicopper(II) cryptate [Cu(II)(2)L(A)](BF(4))(4) 4. Electrochemical studies indicate that L(A) stabilizes the copper(II) oxidation state more effectively than L(I); no copper redox state lower than II,II has been isolated in the solid state using this ligand.     

Solid phase extractors derived by functionalising sub-micro silica gel with chelating agents and their pH-tunable adsorbing capability towards Pb(II) and Ag(I)

Three novel solid phase extraction agents were developed by functionalising sub-micron sized silica gel with organic functional moieties possessing {SN}-ligating atoms. The extractors were characterised by FTIR and TGA. Their capability of adsorbing the ions Fe(III), Cu(II), Zn(II), Cd(II), Cr(VI), Hg(II), Pb(II), Co(II), Ni(II), and Ag(I) is described. The extractors show pH-tunable selectivity for Ag(I) and/or Pb(II). By adjusting the pH to 5 or 6, high affinity is found for both Ag(I) and Pb(II), with little or no interference by the other metal ions. At pH values of <2, the extractors become highly selective for Ag(I), with an adsorption capacity of 35 mg g^?1. Little mechanical stirring is required due to the size of the particles. The recovery rates for both Ag(I) and Pb(II) were better 90% even after five repetitive adsorption-desorption cycles.     

Selective separation of silver(I) and mercury(II) ions in natural water samples using alumina modified thiouracil derivatives as new solid phase extractors

A simple and reliable solid-phase extraction (SPE) method has been developed to synthesise two new sorbents: 6-propyl-2-thiouracil and 5,6-diamino-2-thiouracil physically loaded onto alumina surface, phases I and II, respectively. The synthesis of these new phases has been confirmed by IR-spectroscopy. The surface concentrations of the organic moieties were determined to be 0.182 and 0.562 mmol g^?1 for phases I and II, respectively. The evaluation of the selectivity and metal uptake properties incorporated in these two alumina phases were also studied and discussed for 10 different metal ions: Ca(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Hg(II), Pb(II) and Ag(I) under different controlling factors. The data obtained clearly indicated that the new SP-extractors have the highest affinity for retention of Hg(II) ions. Selective separation of Hg(II) from Ag(I) as one of the most interfering ion, in addition to the other eight coexisting metal ions under investigation, was achieved successfully using the new sorbents at pH = 9.0 under static conditions. Therefore, Hg(II) exhibits major retention percentage (100.0%) using phase I or II. However, Ag(I) exhibits minor retention percentage equal to 1.33% using phase I and 0.67% using phase II. On the other hand, the retention percentage of the other eight metal ions ranged (0.0–3.08%) using phase I and (0.0–1.54%) using phase II at the same pH. The new phases were applied for separation and determination of trace amounts of Hg(II) and Ag(I) spiked natural water samples using cold vapour atomic absorption spectroscopy and atomic absorption spectroscopy with no matrix interference. The high recovery values of Hg(II) and Ag(I) obtained using phases I and II were ranged 98.9 ± 0.1–99.2 ± 0.05% along with a good precision (RSD% 0.01–0.502%, N = 3) demonstrate the accuracy and validity of the new sorbents for separation and determination of Hg(II) and Ag(I).     

Studies in metal sulphite chemistry—III

Manganese(II) iodide, iron(II) iodide and copper(I) iodide each react with tetramethylammonium disulphite to form anhydrous manganese(II) sulphite, iron(II) sulphite and copper(I) disulphite respectively. Iron(II) sulphite and copper(I) disulphite react with dimethylsulphoxide-sulphur dioxide to form iron(II) disulphate and copper(II) disulphate respectively. Hydrated sulphites of manganese(II), iron(II), magnesium(II) and calcium(II) were also prepared. The properties of the sulphites were investigated using thermogravimetric and IR measurements.     

以硫醚为主链的螯合树脂研究Ⅳ．含硫代硫酸根、叠氮基树脂的合成及吸附性能

聚环硫氯丙烷或环硫氯丙烷与环氧氯丙烷共聚物，在少量二乙烯三胺存在下制得交联预聚物，将交联预聚物分别与硫代硫酸钠，叠氮化钠反应，制得四种侧链带有硫代硫酸根或叠氮基的新型螯合树脂。它们对贵金属离子具有较高的吸附容量和较好的吸附选择性。     

Coated-wire silver ion-selective electrode based on silver complex of cyclam.

A coated-wire ion-selective electrode (ISE) based on cyclam (1,4,8,11-tetraazacyclotetradecane) as a neutral carrier in a polyvinyl chloride (PVC) matrix was fabricated for the determination of Ag(I) ions. The coated-wire ISE exhibited a linear Nernstian response over the range 1 x 10(-1) to 1 x 10(-7) M with a slope of 59 +/- 2 mV per decade change and a detection limit of 5 x 10(-8) M. The ISE shows a greater preference for Ag over other cations with good precision. The electrode was selective towards Ag(I) ions in the presence of 13 different metal ions tested. The selectivity coefficients (K(ij)) were determined for Na(I), K(I), Mg(II), Ca(II), Ba(II), Mn(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) and Hg(II). The selectivity coefficients of these cations are in the range of 10(-4) to 10(-2). This ISE was used for the determination of free silver and total silver in electroplating bath solutions, additives and brighteners.     

Tris(2,2′-bipyridyl)iron(II)tetraphenylborate as a solid analytical reagent in the spectrophotometric determination of Ag(I), Tl(I), and Hg(II)

Analytical applications of a new solid reagent tris(2,2′-dipyridyl)iron(II) tetraphenylborate are described. The solid reagent selectively reacts with Ag(I), Tl(I), and Hg(II) cations to release the colored tris(2,2′-bipyridyl)iron(II) cation in solution, which is determined spectrophotometrically. The experimental data show that the Ag(I), Tl(I), and Hg(II) cations respond linearly in 5 to 50-ppm range.     

Spectroelectrochemical studies of some species in fused PbCl2 + KCl at 440°C

The electrochemical reduction of Pb(II), Ag(I). Ni(II), In(III)_and Rh(III), and the oxidation of O(?II), I(?I) and S(?II) have been investigated in a PbCl₂+KCl melt with 23% mol KCl at 440°C, by potentiometry, linear potential sweep and cyclic voltammetry, and potential step chronoamperometry. The potential of the Pb/Pb(II) electrode was found to change linearly with the melt composition. The Ag/Ag(I) system has a Nerstian behaviour and was used as a reference electrode. All species showed a one step oxidation or reduction process, leading to Ni(0), In(I), Rh(0), CO₂ and I₂, except that the sulphide oxidizes in two steps. Absorption of light by Co(II), Ni(II), and Rh(III) was measured with a new device using fibre optics, which allowed us to record the spectrum of Ni(II) and Rh(III) inside the electrolytic cell, during oxidation at controlled potential of a nickel wire, or reduction of Rh(III).     

Selective transport of Ag(Ⅰ) ion across a bulk liquid and polymer membranes incorporated with di-N-benzylated O_3N_2 donor macrocycles

<正>The selective bulk liquid membrane and polymer membrane transports of Ag(Ⅰ) from an aqueous solution containing seven metal cations,Co(Ⅱ),Ni(Ⅱ),Cu(Ⅱ),Zn(Ⅱ),Ag(Ⅰ),Cd(Ⅱ) and Pb(Ⅱ),was studied.The source phases contained equimolar concentrations of the above-mentioned cations,with the source and receiving phases being buffered at pH 5.0 and 3.0,respectively. Ag(Ⅰ) ion transport occurred with a good efficiency from the aqueous source phases across the bulk liquid membrane and polymer membrane(derived from cellulose triacetate) containing ligand 1 as the ionophores,into the aqueous receiving phases.Clear transport selectivity for Ag(Ⅰ) was observed using ligand 1.There was no selectivity for the cations using ligand 2 in the both bulk liquid membrane and polymer membrane transports.     

Molecular and crystal structure of pyrylium squarylium dyes

The crystal structures of new dyes: 4-[[3-[[2,6-bis-(tert-butyl)-4H-pyran-4-ylidene]methyl]-2-oxido-4-oxo2-cyclobuten-]-ylidene]methyl]2,6-bis(tert-butyl)pyrylium (I) and its thio analog (II) were determined. Crystal data: space group P1 (I), P2₁/n (II); a = 5.960(9) ? (I), 10.400(4) ? (II); b = 9.366(3) ? (I), 12.242(4) ? (II); c = 13.948(3) ? (I), 14.482(6) ? (II); α = 70.43(2)° (I), 90.0° (II); ? = 84.82(9)° (I), 94.65(3)° (II); γ = 79.10(9)° (I), 90.0° (II); V = 720.0 ?³ (I), 1837.7 ?³ (II); Z = I (I), 2 (II); d_calc = 1.131 g/cm³ (I), 086 g/cm³ (II); R1(F) 0.049 (I), 0.045 (II). The substituents are trans-oriented relative to the planar 4-membered ring. Bond length distribution points to a considerable electron density delocalization over the whole molecule except the Bu^t groups. The pyrane rings are oriented differently relative to the central group; in II the rings lie in the same plane which is rotated through 7.7° with respect to the central fragment, whereas in I they lie in parallel planes which are 1.38 ? apart and deviate from the central fragment to opposite sides, forming with it dihedral angles of 12.8°. These conformational differences are possibly the result of the action of crystal field forces. In I molecules are arranged as overlapping stacks, whereas in II the pairwise parallel dye molecules are oriented in such a way that their long molecular axes are perpendicular to the long axes of the neighboring pair, resulting in a herringbone packing. Translated fromZhurnal Strukturnoi Khimii, Vol. 41, No. 4, pp. 781-787, July-August, 2000     

Polarographische und oszillopolarographische Untersuchungen in Trimethylphosphat

Zusammenfassung Das polarographische und oszillopolarographische Verhalten der Perchlorate von Tl(I), Rb(I), K(I), Na(I), Ba(II), Zn(II), Cd(II), Mn(II), Co(II), Ni(II) sowie von Bisbiphenylchrom(I) jodid wurde in wasserfr. Trimethylphosphat (0,1M-Tetraäthylammoniumperchlorat) untersucht. Die Halbwellenpotentiale bei 25° gegen die gesättigte wäßr. Kalomelelektrode werden auf die Bisbiphenylchrom(I)jodid-Skala bezogen.Die Beziehung zwischen Donorzahl des Lösungsmittels undE _1/2 ist erfüllt. Eine Ausnahme, welche auf Chelatbildung zurückzuführen sein dürfte, bilden die in Trimethylphosphat gemessenen Werte für Mn(II), Co(II) und Ni(II).

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Polarographic and oscillopolarographic investigations in trimthhyl phosphate

Polarographic and oscillopolarographic investigations have been carried out on the perchlorates of Tl(I), Rb(I), K(I), Na(I), Ba(II), Zn(II), Cd(II), Mn(II), Co(II), Ni(II) and of bisbiphenylchromium(I)iodide in anhydrous trimethylphosphate (0,1M tetraethylammoniumperchlorate). The half-wave potentials at 25° vs. the aqueous saturated calomel electrode are referred to the bisbiphenylchromium(I)iodide-scale. The relationship between donor number of the solvent andE _1/2 is observed. An exception is given for Mn(II), Co(II) and Ni(II) in trimethylphosphate, which is regarded as due to chelate formation.

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Mit 5 Abbildungen     

Synthesis and Metal Collecting Properties of Mono,Di, Tri and Tetramine Based on Silica Gel Matrix

Abstract

Silica gels, chemically modified with mono, di, tri and tetramine (I - IV), were synthesized. The monoamine (I) was produced directly via the reaction of silica gel with 3-aminopropyltrimethoxysilane. The diamine (II), triamine (III) and tetramine (IV) were produced through the reaction of ethylenediamine (EDA), diethylenetriamine (DETA) and triethylenetetramine (TETA) with 3-chloropropyltrichloromethane modified silica gel, respectively. The sorption properties of the phases (I - IV) toward Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Pb(II) were investigated at different pH-values based on the batch equilibrium technique, The, metal uptake capacities (mmol/g) were determined and discussed in terms of the structure of the aliphatic amines and the increasing number of nitrogen donor atoms. The metal capacity values demonstrate the higher efficiency of phases III and IV than phases I and II for preconcentration of such metal ions. Moreover, the use of phases III and IV for selective extraction of Cu(II) and Ni(II) is promising.     

Molecular and crystal structure of pyrylium squarylium dyes

The crystal structures of new dyes: 4-[[3-[[2,6-bis-(tert-butyl)-4H-pyran-4-ylidene]methyl]-2-oxido-4-oxo2-cyclobuten-]-ylidene]methyl]2,6-bis(tert-butyl)pyrylium (I) and its thio analog (II) were determined. Crystal data: space group P1 (I), P2₁/n (II); a = 5.960(9) Å (I), 10.400(4) Å (II); b = 9.366(3) Å (I), 12.242(4) Å (II); c = 13.948(3) Å (I), 14.482(6) Å (II); α = 70.43(2)° (I), 90.0° (II); ß = 84.82(9)° (I), 94.65(3)° (II); γ = 79.10(9)° (I), 90.0° (II); V = 720.0 ų (I), 1837.7 ų (II); Z = I (I), 2 (II); d_calc = 1.131 g/cm³ (I), 086 g/cm³ (II); R1(F) 0.049 (I), 0.045 (II). The substituents are trans-oriented relative to the planar 4-membered ring. Bond length distribution points to a considerable electron density delocalization over the whole molecule except the Bu^t groups. The pyrane rings are oriented differently relative to the central group; in II the rings lie in the same plane which is rotated through 7.7° with respect to the central fragment, whereas in I they lie in parallel planes which are 1.38 Å apart and deviate from the central fragment to opposite sides, forming with it dihedral angles of 12.8°. These conformational differences are possibly the result of the action of crystal field forces. In I molecules are arranged as overlapping stacks, whereas in II the pairwise parallel dye molecules are oriented in such a way that their long molecular axes are perpendicular to the long axes of the neighboring pair, resulting in a herringbone packing.     

Solvent extraction of metals with macrocyclic compounds. I

Summary The extractants studied in this work are 5,6; 14,15-dibenzo-l,4-dioxa-8,12-diazacyclopentadeca-7,12-diene (I) and 5,6; 14,15-dibenzo-1,4-dioxa-8,12-diazacyclopentadecane (II). Radioactive nuclides were used to investigate the extraction of Ag(I), Hg(II), Cu(II), Cd, Co(II), Zn, Fe(III), Mn(II), and Pd with chloroform solutions of I and II. It is shown that compound I extracts only silver. The composition of the extracted compound has been established: silver is extracted as an AgLX complexe (L being macrocycle I and X being the counterion). The counterions involved in the experiment were perchlorate, picrate (Pi), and dipicrylaminate (DPA); the extraction of silver is intensified in the series: ClO₄ ^–––. The solvents used include nitrobenzene, 1,2-dichloroethane, chloroform, ando-xylene, the best being nitrobenzene and dichloroethane. Macrocycle II was found to exhibit poorer selectivity; in addition to Ag(I), it also extracts Hg(II), Cu(II) and Pd. The lower selectivity of macrocycle II, as compared to that of I, must be due to the graeter comformational mobility of molecule II.

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Metallextraktion durch makrocykliscbe Verbindungen. I

Zusammenfassung 5,6; 14,15-Dibenzo-1,4-dioxa-8,12-diazacyklopentadeka-7,12-dien (i) und 5,6; 14,15-Dibenzo-1,4-dioxa-8,12-diazacyklopentadekan (II) wurden als Extraktionsmittel verwendet. Radioaktive Nuklide dienten zur Untersuchung der Extraktion von Ag(I), Hg(II), Cu(II), Cd, Co(II), Zn, Fe(III), Mn(II) und Pd durch Chloroformlösungen von I und II. Die Verbindung I extrahiert nur Silber. Die Zusammensetzung der extrahierten Verbindungen wurde ermittelt: Silber wird als AgLX (L=Makrocyklus I, X=Gegenion) extrahiert. Als Gegenionen wurden Perchlorat, Pikrat (Pi) und Dipikrylaminat (DPA) verwendet. Die Extraktion von Silber wächst in der Reihenfolge ClO₄     

A selective chemosensor for detection of Ag(I) and Cu(I) based on an acenaphthoquinone derivative and its complexes

A new Schiff base, acenaphthoquinone bis(diphenylmethlenehydrazone) (L), was synthesized and employed as a chemosensor for detecting Ag(I) and Cu(I). Experimental results showed that the chemosensor exhibited high selectivity and sensitivity. The sensitivity of the chemosensor for Ag(I) or Cu(I) was not affected by other metal ions, such as Ni(II), Nd(III), Zn(II), Fe(III), Cu(II), Na(I), La(III), K(I), and Co(II). Complexes 1 and 2 were synthesized by coordination of L with Ag(I) and Cu(I), respectively. The crystal structures of 1 and 2 were determined by single-crystal X-ray diffraction. They had the same space group P2₁/c. Based on theoretical calculation, mechanism of the chemosensor detecting Ag(I) and Cu(I) was suggested.     

以硫醚为主链的螯合树脂研究Ⅰ.4-氨基安替吡啉树脂和乙基原磺酸基树脂的合成及吸附性能

聚环硫氯丙烷或环硫氯丙烷与环氧氯丙烷共聚物，在少量二乙烯三胺存在下制得交联预聚物，将交联预聚物与4－氨基安替吡啉（4AAP）或乙基原磺酸钾（PEA）反应，制得四种侧链带氨基安替吡啉，乙基原碘酸基的新型螯合树脂。它们对贵金属具有优良的吸附性能和高的吸附选择性。并通过X－射线光电子能谱初步探讨了树脂对金属离子的螯合作用。     

以硫醚为主链的螯合树脂研究——Ⅲ.含硫氰酸根树脂的合成及吸附性能

环硫氯丙烷的均聚物或环硫氯丙烷与环氧氯丙烷的共聚物,在少量二乙烯三胺存在下制得预交联聚合物,将后者与硫氰化钾反应,制得两种侧链带有硫氰酸根的新型螯合树脂。它们对贵金属具有优良的吸附性能和高的吸附选择性。通过X射线光电予能谱初步探讨了树脂对金属离子的螯合作用     

Heterodinuclear metal arrangement in a flat macrocycle with two chemically-equivalent metal chelating sites

A phenanthroline-based macrocycle 1 has been newly developed which has two chemically equivalent metal chelating sites within the spatially restricted cavity for dinuclear metal arrangement. The macrocycle 1 reacts with Zn(CF(3)CO(2))(2) or ZnCl(2) to form homodinuclear Zn(II)-complexes. A single-crystal X-ray structural analysis of the resulting Zn(2)1(CF(3)CO(2))(4) determined the complex structure in which two Zn(II) ions are bound by two phenanthroline sites and two CF(3)CO(2)(-) ions bind to each Zn(II) ion in a tetrahedral geometry. Similarly, a homodinuclear Cu(I)-macrocycle was formed from 1 and Cu(CH(3)CN)(4)BF(4). Notably, from 1 and an equimolar mixture of Cu(CH(3)CN)(4)BF(4) and Zn(CF(3)CO(2))(2), a heterodinuclear Cu(I)-Zn(II)-macrocycle was exclusively formed in high yield (>90%) because of the relatively low stability of the dinuclear Cu(I)-macrocycle. A heterodinuclear Ag(I)-Zn(II)-macrocycle was similarly formed with fairly high selectivity from a mixture of Ag(I) and Zn(II) ions. Such selective heterodinuclear metal arrangement was not observed with other combinations of M-Zn(II) (M = Li(I), Mg(II), Pd(II), Hg(II), La(III), and Tb(III)).     

Synthesis and characterization of silica gel microspheres encapsulated by salicyclic acid functionalized polystyrene and its adsorption of transition metal ions from aqueous solutions

The present study was undertaken to develop a novel adsorbent for heavy metal ions, and this paper presents the synthesis and characterization of a composite material-silica gel microspheres encapsulated by salicyclic acid functionalized polystyrene (SG-PS-azo-SA) with a core-shell structure. SG-PS-azo-SA was used to investigate the adsorption of Mn(II), Co(II), Ni(II), Fe(III), Hg(II), Zn(II), Cd(II), Cr(VI), Pd(II), Cu(II), Ag(I), and Au(III) from aqueous solutions. The results revealed that SG-PS-azo-SA has better adsorption capacity for Cu(II), Ag(I) and Au(III). Langmuir and Freundlich isotherm models were applied to analyze the experimental data, the best interpretation for the experimental data was given by the Langmuir isotherm equation with the maximum adsorption capacity for Cu(II), Ag(I), and Au(III) at 1.288 mmol g⁻¹, 1.850 mmol g⁻¹ and 1.613 mmol g^t-1, respectively. Thus, silica gel encapsulated by salicyclic acid functionalized polystyrene (SG-PS-azo-SA) is favorable and useful for the removal of Cu(II), Ag(I) and Au(III) metal ions.     

Complexing properties of N-2-sulfoethyl chitosans

For a new sulfoethylated chitosan derivative with the degree of substitution of amino group hydrogen atoms of 0.5, the dissociation constant of functional groups has been determined by potentiometric titration. Complexing properties of sulfoethylated chitosan toward copper(II), cobalt(II), nickel(II), zinc(II), manganese(II), cadmium(II), silver(I), lead(II), magnesium(II), calcium(II), strontium(II), and barium(II) ions have been studied potentiometrically. Alkaline earth and magnesium ions do not form complexes with sulfoethylated chitosan. For the other ions, stability constants of the resulting complexes have been determined. The most stable N-2-sulfoethyl chitosan complexes are those with copper(II) and silver(I) ions.