Crescent aromatic oligothioamides as highly selective receptors for copper(Ⅱ) ion

A series of crescent aromatic oligothioamides(4, 6, 8, 15, and 18) bearing different number of sulfur atoms were designed and synthesized via thionation of their corresponding aromatic oligoamides(3, 5, and 7) using Lawesson's reagent. The X-ray structure of a trimeric analogue(13) revealed the presence of intramolecular three-center hydrogen bonds that are responsible for the rigidification of the molecular backbone. The extraction by these novel receptors toward some representative heavy metal cations(Zn2+, Cd2+, Co2+, Ni2+, Pb2+, and Cu2+) and alkali and alkaline earth metal cations(Li+, Na+, K+, Rb+, Cs+, Ca2+, and Sr2+) demonstrated high efficiency(83.5%–96.4%) and superior selectivity for Cu2+ over other selected metal cations. Particularly, the extractability was correlated to both the number of sulfur atoms and orientation of thiocarbonyl groups as revealed in the order: 6 4 18 15. This is in stark contrast to the oligoamides that only gave much lower extractability(5.9%–16.4%), suggestive of the importance of replacement of carbonyl oxygen atoms with sulfur atoms in the extraction of Cu2+. The complexation behavior of 4, 6, and 8 with Cu2+ was also examined by UV-Vis and NMR techniques.     

Spectrophotometric microdetermination of iron(III) by tris-pyrrolidone(5)-hydroxamato(2)-chelate

The optimum conditions for the spectrophotometric determination of iron(III) with neutrial tris-PIH-chelate are: pH = 5, λ = 430 nm, PIH concentration 2 × 10⁻² M, and iron (III) concentration (0.6–3.3) × 10⁻⁴ M. Under these conditions the suggested method conforms to Beer's law and the molar absorptivity is 2800. The relative accuracy is ±0.48% based upon evaluation from the calibration curve and ±1.02% based upon algebraic equations. The precision is ±0.53% as deviation from the mean, and 0.69% as SD.The suggested method suffers from no interference from Fe²⁺, Al³⁺, Cr³⁺, Pb²⁺, Hg²⁺, Cd²⁺, Ni²⁺, Co²⁺, Zn²⁺, Mn²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Mg²⁺, Ag⁺, F⁻, and tartrate, but interference is caused by U⁶⁺, V⁵⁺, Mo²⁺, Cu²⁺, (in larger concentrations) or by oxalate and citrate. The method may be used either as a sensitive spectrophotometric or visual method.     

Polarographic and voltammetric investigations in N-methylpyrrolidinone(2) and N-methylthiopyrrolidinone(2)

Polarographic and voltammetric methods were employed to study the influence of N-methylpyrrolidinone(2) (NMP) and N-methylthiopyrrolidinone(2) (NMTP) towards a series of cations. In NMP reversible electrode reactions were observed for Na⁺, K⁺, Tl⁺, Zn²⁺, Cd²⁺, Cu²⁺, Ag⁺ and irreversible reductions for Ba²⁺, Mn²⁺, Co²⁺ and Ni²⁺. 0.1 mol l^?1 tetraethylammoniumperchlorate solutions served as supporting electrolytes. Li⁺ was not electroactive in the supporting electrolyte mentioned, but yielded an irreversible cathodic wave in tetra-n-butylammonium perchlorate. In NMTP, Li⁺, Na⁺, Tl⁺, Zn²⁺, Cd²⁺, Cu⁺ and Ag⁺ gave reversible cathodic waves on the DME, while Mn²⁺, Co²⁺ and Ni²⁺ were reduced in an irreversible electrode process. Bisbiphenylchromium iodide serving as a reference system throughout this study showed reversible behaviour in both solvents. A comparison of E_1/2 for given ions in both solvents showed a shift of about 0.5 V to more positive values in the case of a typically hard cation such as Na⁺ whereas soft cations such as Ag⁺ and Cu⁺ shifted by more than 0.8 V to more negative values. The effects of these two solvents on the cations studied is discussed in terms of donor acceptor interactions between the cation and the solvent molecules with special respect to the changes caused by replacing the oxygen atom in NMP by a sulphur atom.     

Gas-phase synthesis of lanthanide(III) benzoates Ln(Bz)<Subscript>3</Subscript> (Ln = La,Tb, Lu)

A new method for the synthesis and film deposition of nonvolatile aromatic lanthanide(III) carboxylates by ligand exchange reaction between the starting volatile components in the gas phase was proposed. The complexes Ln(Bz)₃ (Ln = La³⁺, Tb³⁺, Lu³⁺, HBz = benzoic acid) were synthesized by gas-phase ligand exchange reaction between the volatile Ln(Thd)₃ and HBz (HThd = 2,2,6,6-tetramethylheptane-3,5-dione). The composition of the complexes was confirmed by elemental, thermal, IR-spectroscopic, and photoluminescence analyses and, in the case of lanthanum and lutetium complexes, by ¹H NMR.     

Extraktiv-photometrische Eisenbestimmung als Tris-(Dibenzylsulfoxid) Eisen(III)-rhodanid

Zusammenfassung Die Extraktion des Eisens aus 0,5-n salzsaurer Lösung, die 3% Kaliumrhodanid enthält, in 8%ige Lösung von Dibenzylsulfoxid in Methylenchlorid ermöglicht bei 500 nm die extraktiv-photometrische Bestimmung von 5 bis 100g Fe³⁺ als [Fe(CNS)₃(OS{CH₂C₆H₅}₂)₃]. Es werden neben Bi³⁺, Cr³⁺, Mg²⁺, Zn²⁺ Spezifitäten Fe³⁺: Fremdion = 110⁴, neben Al³⁺, Ca²⁺, Cd²⁺, Co²⁺, Hg²⁺, Mn²⁺, Ni²⁺, VO²⁺, Zr⁴⁺ solche von 110⁵ und darüber erreicht. An verschiedenartigen Beispielen wird die Anwendbarkeit des Verfahrens ausgewiesen.

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Extractive-photometric iron determination as tris(dibenzylsulfoxide) iron(III)-thiocyanate

Summary The extraction of iron from 0.5N hydrochloric acid solution, that contains 3% potassium thiocyanate, into 8% solution of dibenzylsulfoxide in methylene chloride makes possible the extractive-photometric determination at 500 nm of 5–100g of Fe³⁺ as [Fe(CNS)₃(OS{CH₂C₆H₅}₂)₃]. Specifities for Fe³⁺: foreign ion = 110⁴ are attained in the presence of Bi³⁺, Mg²⁺, Zn²⁺, and specificities of 110⁵ and above have been reached in the presence of Al³⁺, Ca²⁺, Cd²⁺, Co²⁺, Hg²⁺, Mn²⁺, Ni²⁺, VO²⁺, Zr⁴⁺. The applicability of the procedure has been demonstrated on various specimens.

     

Microdetermination of uranium (VI)

Summary A new method has been evolved for the separation and estimation of UO₂ ²⁺ from Cu²⁺, Zn²⁺, Ag⁺, Pb²⁺, Ga³⁺, In³⁺, Tl³⁺, La³⁺, Ti⁴⁺, Zr⁴⁺ and Th⁴⁺ with the sodium salt of benzilic acid as precipitating and chelating agent andn-butanol as solvent for solvent extraction. All these cations except UO₂ ²⁺ are precipitated by benzilic acid; UO₂ ²⁺ forms a deep yellow complex extractable byn-butanol. The uranium can be determined in the organic phase spectrophotometrically at 430 nm. The pH range over which the separation can be carried out is 2.6–4.0. Few anions and cations interfere.

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Zusammenfassung Eine neue Methode der Trennung und Bestimmung von UO₂ ²⁺ neben Cu²⁺, Zn²⁺, Ag⁺, Pb²⁺, Ga³⁺, In³⁺, Tl²⁺, La³⁺, Ti⁴⁺, Zr⁴⁺ und Th⁴⁺ wurde ausgearbeitet. Das Natriumsalz der Benzilsäure dient als Färbungs- und Komplexbildungsmittel und n-Butanol zur Extraktion. Alle angeführten Kationen mit Ausnahme von UO₂ ²⁺ werden von Benzilsäure gefällt; UO^{2 2+} bildet einen tiefgelben, mit n-Butanol extrahierbaren Komplex und kann in der organischen Phase spektrophotometrisch bei 430 nm bestimmt werden. Die Trennung kann bei pH 2,6 bis 4,0 durchgeführt werden. Nur wenige Anionen und Kationen stören.

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Résumé On développe une nouvelle méthode pour la séparation et l'évaluation de UO₂ ²⁺ dans Cu²⁺, Zn²⁺, Ag⁺, Pb²⁺, Ga³⁺, In³⁺, Tl³⁺, La³⁺, Ti⁴⁺, Zr⁴⁺ et Th⁴⁺, par le sel de sodium de l'acide benzilique comme agent précipitant et chélatant et le N-butanol comme solvant pour l'extraction par solvant. Tous ces cations, sauf UO₂ ²⁺, précipitent par l'acide benzilique; UO₂ ²⁺ forme un complexe jaune intense que l'on peut extraire par le N-butanol. On peut doser l'uranium en phase organique par spectrophotométrie à 430 nm. La séparation peut s'effectuer dans le domaine de pH de 2,6 à 4,0. Peu d'anions et de cations interfèrent.

     

Anwendung von 1-(2-Pyridylazo)-2-naphthol (PAN) in der Spurenanalyse

Zusammenfassung Die Reaktionsbedingungen von PAN mit VO₂ ⁺, Mn²⁺, Fe³⁺, Co³⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Ga³⁺, In³⁺ und Tl³⁺ wurden systematisch untersucht. Die Abhängigkeit der Extinktion vom pH-Wert der Lösung, die Lage der Absorptionsmaxima und die Empfindlichkeit der betreffenden Reaktionen werden angegeben. Im Vergleich zu anderen hochempfindlichen Metallreagentien zeigt PAN zahlreiche Vorteile. Die Möglichkeiten zur Erhöhung der Selektivität werden erörtert. Die Anwendbarkeit von PAN in der Spurenanalyse wird diskutiert.

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Summary The conditions for the reaction of PAN with VO₂ ⁺, Mn²⁺, Fe³⁺, Co³⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Ga²⁺, In³⁺ and Tl³⁺ are studied systematically. The dependence of the absorption on the pH of the solution, the position of the absorption maxima, and the sensitivity are given for these PAN chelates. PAN shows numerous advantages in comparison with other highly sensitive metal reagents. Possibilities for increasing the selectivity of PAN reactions are dealt with. The application of PAN in trace analysis is discussed.

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Auszugsweise vorgetragen bei der Analytikertagung in Lindau, 13.–16. April 1966.     

Metal Chelates of Cerium (III), Thorium(IV) and Dioxouranium(VI) with Some Heterocyclic AZO Dyes; Potentiometric and Spectrophotometric Studies

ABSTRACT

The stepwise formation constants of Ce³⁺, Th⁴⁺ and UO₂ ²⁺ complexes with four azo compounds based on I-phenyl-2, 3-dimethylpyrazoline-5-one nucleus namely; 4-phenylazo- (2-hydroxy, 5-x) 1-pheny1-2, 3-dimethy1-pyrazoline-5-one, where x= H (1), OH (II), COOH (III) and NH₂ (IV) have been determined potentiometrically at different temperatures and ionic strengths in 30% (v/v) ethanol-water solutions, then the thermodynamic parameters are calculated.

Negatives values of both ∠H and ∠G are obtained indicating the exothermic and spontaneous nature of complexation reactions, whereas positive values of ∠S show that entropy consideration favour complex formation. The study at different ionic strengths shows that an increase in the latter causes a decrese in the pK values. The azo compounds are also tested as new reagents for the spectrophotometric determination of Ce³⁺, Th4⁺ and UO₂ ²⁺ ions in synthetic and natural solutions by extensive investigation of the optimum conditions favoring the formation of colored complexes.     

Synthesis of a novel poly(para‐phenylene ethynylene) for highly selective and sensitive sensing mercury (II) ions

A new poly(p‐phenylene ethynylene) derivative with pendant 2,2′‐bipyridyl groups and glycol units (PPE‐bipy) has been prepared, and its metal ion sensing properties were investigated. The polymer of PPE‐bipy exhibited high selectivity for Hg²⁺ as compared with Li⁺, Na⁺, K⁺, Ba²⁺, Ca²⁺, Mg²⁺, Al³⁺, Mn²⁺, Ag⁺, Zn²⁺, Pb²⁺, Ni²⁺, Cd²⁺, Cu²⁺, Co,²⁺ and Fe³⁺ in THF/EtOH (1:1, v/v) solution. The fluorescence of PPE‐bipy was efficiently quenched by Hg²⁺ ions, and the detection limit was found to be 8.0 nM in a THF/EtOH (1:1, v/v) solvent system. PPE‐bipy also showed a selective chromogenic behavior toward Hg²⁺ ions by changing the color of the solution from slight yellow to colorless, which can be detected with the naked eye. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1998–2007, 2008     

Crystal structure of enrofloxacinium tetrabromidodichloridostannate(IV) monohydrate

A new compound EnrH₃[SnBr_3.46Cl_2.54]·H₂O, where EnrH ₃ ²⁺ is the enrofloxacinium cation (C₁₉H₂₄FN₃O ₃ ²⁺ ), is synthesized and its crystal and molecular structure is determined. Crystallographic data for enrofloxacinium tetrabromidodichloridostannate(IV) monohydrate are as follows: a = 17.1262(19) Å, b = 10.3435(11) Å, c = 17.2582(19) Å, β = 119.203(1)°, V = 2640.5(4) ų, space group P2₁/c, Z = 4. Hydrogen bonds form a branched three-dimensional network linking EnrH ₃ ²⁺ , [SnBr_3.46Cl_2.54]^2?, and water molecules. The structure is also stabilized by the π-π interaction of EnrH ₃ ²⁺ aromatic rings.     

Poly(ethyleneiminoacetic acid)

A high molecular weight chelating polymer has been prepared by the reaction of poly(ethyleneimine) of molecular weight 50–100 × 10³ with a basic solution of sodium chloroacetate. The polymer which results from this reaction is hydrophilic and possesses rather generalized coordinating abilities. It forms complexes with Hg²⁺, Ca²⁺, Al³⁺, Fe²⁺, Zn²⁺, Pb²⁺, La³⁺, Nd³⁺ and Cd²⁺. Some of the metal complexes show a much lower solubility than the parent chelating polymer. Both the poly(ethyleneiminoacetic acid) and its calcium complex possess thermal and chemical stabilities comparable to that found for EDTA and its calcium complex.     

Quantitative Separation of Hg(11) From Several Metal Ions on Zr(IV) Antimonate Papers

Abstract

The chromatographic behaviour of 32 metal ions has been studied on paper Impregnated with Zirconium(IV) antimonate in aqueous HCI and mixed solvent system containing dimethyisul phoxide and dioxane. Several Important binary and ternary separations have been achieved. Quantitative separation of Hg(ll) from Ni²⁺, Pb²⁺, Pd²⁺, Ru³⁺, Rh³⁺, Bi³⁺, Co²⁺, Cd²⁺ and Gd³⁺ is described.     

Pb2+-Containing Metal-Organic Rotaxane Frameworks (MORFs)

The metal-organic rotaxane framework (MORF) structures with the advantage of mechanically interlocking molecules (MIMs) have attracted intense interest from the chemical community. In this study, a set of MORFs (i.e., MORF-Pb-1 and MORF-Pb-2) are constructed using Pb²⁺, a tetraimidazolium macrocycle (Texas-sized molecular box; 1⁴⁺), and aromatic dicarboxylate (p-phthalate dianions (PTADAs; 2) or 2,6-naphthalene dicarboxylate dianions (3)) via a one-pot three-layer diffusion protocol. In particular, an unusual Pb…Pb weak interaction was shown in MORF-Pb-1 (charactered with distance of 3.656 Å).     

Spectrophotometric determination of molybdenum(vi) with benzoylacetanilide

Abstract

The complex formed between molybdenum(VI) and benzoylacetanilide in the pH range 0.6 and 1.9 has been extracted into methyl isobutyl ketone and the absorbance has been measured at 410 mμ. Quantities of 0.15 to 2.10 mg of molybdenum have been determined with a standard deviation of 0.6%. The color is stable up to 2 hours. The presence of Co²⁺, Ni²⁺, Zn²⁺, Mn²⁺, Be²⁺, Al³⁺, Cr³⁺, Ce⁴⁺, Th⁴⁺ or UO²⁺ ₂ up to 100 μg causes no interference. Ordinarily, Fe³⁺ interferes with the determination, but when masked with 1 ml of 0.5% solution of ascorbic acid the tolerance limit is 10 mg. Thus, molybdenum can be determined in steel when present in amounts as low as 0.26%.     

Metallchelate ungesättigter geminaler Dichalcogenoliganden mit gemischten S,Se-Ligatoren Kristall- und Molekülstruktur von Tetra-n-butylammonium-bis(1,1-dicyanoethylen-2,2-thioselenolato)nickelat(II), [(n-C4H9)4N]2[Ni(SSeC?C(CN)2)2]

Metal Chelates of Unsaturated Geminal Dichalcogeno Ligands Containing S as well as Se Ligators. Crystal and Molecular Structure of Tetra-n-butylammonium-bis(1,1-dicyanoethylene-2,2-thioselenolato)nickelate(II), [(n-C₄H₉)₄N]₂[Ni(SSeC? C(CN)₂)₂] Synthesis and properties of chelates of the thioseleno ligands 1,1-dicyanoethylene-2,2-thioselenolate (bis-chelates with Ni²⁺, Pd²⁺, Pt²⁺, Cu²⁺, Au³⁺, Zn²⁺, Cd²⁺, Se²⁺, Te²⁺, UO₂²⁺; tris-chelate mit Cr³⁺, Fe³⁺, Co³⁺, Rh³⁺, In³⁺; 1:1-chelate mit Cu⁺, Au⁺), cyanthioselenocarbimate (bis-chelates with Ni²⁺, Pd²⁺) and 0-β-methoxyethyl-thioselenocarbonate (bis-chelates with Ni²⁺, Pd²⁺, Pt²⁺, Zn²⁺; tris-chelate mit Cr³⁺, Co³⁺, Rh³⁺) are reported. The X-ray crystal structure of [(n-C₄H₉)₄N]₂[Ni(SSeC? C(CN)₂)₂] shows a planar NiS₂Se₂ arrangement. From the space group P2₁/c (a = 14,043(1) Å, b = 8.704(1) Å, c = 20.647(2) Å, β = 108.56(1)°) and Z = 2 follows a trans position of the thioseleno ligands. The same magnitude of the C–S and C–Se distance refers to a hindrance of the equalization of the bonding in the chelate. The structure is compared with those of similar compounds.     

ICT-based Cu(II)-sensing 9,10-anthraquinonecalix[4]crown

A series of calix[4]arene-based chromogenic sensors bearing the 9,10-anthraquinone moiety have been synthesized and examined for their abilities to recognize various cations such as Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺, Ag⁺, Cd²⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Zn²⁺, Hg²⁺, Pb²⁺, Co²⁺, and Cu²⁺ by UV-vis spectroscopy. In acetonitrile, the presence of Cu²⁺ induces the formation of the 1:1 ligand/metal complex, which exhibits a new absorption band centered at 450 nm, and leads to an obvious color change from yellow to red.     

The Synthesis of a Bis(thiosemicarbazone) Macrocyclic Ligand and the Mn(II), Co(II), Zn(II) and 68Ga(III) Complexes

A 1,4,7,10-tetraazacyclododecane (cyclen) variant bearing two thiosemicarbazone pendant groups has been prepared. The ligand forms complexes with Mn²⁺, Co²⁺ and Zn²⁺. X-ray crystallography of the Mn²⁺, Co²⁺ and Zn²⁺ complexes showed that the ligand provides a six-coordinate environment for the metal ions. The Mn²⁺ and Zn²⁺ complexes exist in the solid state as racemic mixtures of the Δ(δ,δ,δ,δ)/Λ(λ,λ,λ,λ) and Δ(λ,λ,λ,λ)/Λ(δ,δ,δ,δ) diastereomers, and the Co²⁺ complex exists as the Δ(δ,δ,δ,δ)/Λ(λ,λ,λ,λ) and Δ(λ,λ,λ,δ)/Λ(δ,δ,δ,λ) diastereomers. Density functional theory calculations indicated that the relative energies of the diastereomers are within 10 kJ mol⁻¹. Magnetic susceptibility of the complexes indicated that both the Mn²⁺ and Co²⁺ ions are high spin. The ligand was radiolabelled with gallium-68, in the interest of developing new positron emission tomography imaging agents, which produced a single species in high radiochemical purity (>95%) at 90 °C for 10 min.     

A highly selective turn-on fluorescent chemosensor for copper(II) ion

A new pyrene derivative (1) containing a diaminomaleonitrile moiety exhibits high selectivity for Cu²⁺ detection. Significant fluorescence enhancement was observed with chemosensor 1 in the presence of Cu²⁺. However, the metal ions Ag⁺, Ca²⁺, Cd²⁺, Co²⁺, Fe²⁺, Fe³⁺, Hg²⁺, Mg²⁺, Mn²⁺, Ni²⁺, Pb²⁺, and Zn²⁺ produced only minor changes in fluorescence values for the system. The apparent association constant (K_a) of Cu²⁺ binding in chemosensor 1 was found to be 5.55×10³ M⁻¹. The maximum fluorescence enhancement caused by Cu²⁺ binding in chemosensor 1 was observed over the pH range 5-7.5.     

An acyclic,dansyl based colorimetric and fluorescent chemosensor for Hg(II) via twisted intramolecular charge transfer (TICT)

An efficient fluorescent chemosensor for Hg²⁺ ion, based on 5-(dimethylamino)-N-(2-mercaptophenyl)naphthalene-1-sulfonamide, has been developed. It exhibits Hg²⁺-selective on–off fluorescence quenching behavior via twisted intramolecular charge transfer (TICT) mechanism, which is rationalized by time dependent density functional theory (TD-DFT) calculations. The system exhibits visible color change from colorless to gray upon Hg²⁺ binding with very high selectivity and sensitivity (as low as 5.0 × 10⁻¹⁰ mol L⁻¹) over other metal ions such as K⁺, Na⁺, Ag⁺, Mn²⁺, Ca²⁺, Ba²⁺, Fe²⁺, Zn²⁺, Pb²⁺, Cu²⁺, Sn²⁺, Cd²⁺, Ni²⁺ and Co²⁺. The present sensing system is also successfully applied for the detection of Hg²⁺ ion in real samples.     

A new coated-wire cobalt(II)-selective electrode based on the benzalkonium tetrathiocyanatocobaltate(II) ion pair

A cobalt-selective electrode based on the benzalkonium tetrathiocyanatocobaltate(II) ion pair is described. The response is Nemstian (slope 29.3 $\text{mV}\text{pCo}$) in the cobalt concentration range 10^-1–10^-4 M in solutions with a constant ionic strength of 3.0 M made up with KSCN at 25°C. The electrode is suitable for end-point detection in titrations of cobalt(II) with EDTA as well as for direct potentiometric determinations of cobalt(II), even in the presence of large amounts of several metal ions (Ni²⁺, Fe²⁺, Mn²⁺, Mg²⁺, Ca²⁺, Ba²⁺) and anions (HCO₃^-, Br^-, I^-, NO₃^-, SO₄^2-).