Polymetallic complexes: Part XI,cobalt(II), nickel(II), copper(II), manganese(II), zinc(II), cadmium(II) and mercury(II) complexes with ON−NO tetradentate Schiff base,N,N'-bis(benzoin) benzidine

Summary The ON–NO donor Schiff base,N,N'-bis(benzoin)benzidine forms mono-, di- and tetra-nuclear complexes with metal cations. The cobalt(II) complex is a blue monomei of tetrahedral configuration. The nickel(II) and manganese(II) complexes are dimers and octahedral. A tetranuclear square planar chloro-bridged structure is proposed for the copper(II) complex. A dimeric pentacoordinated square pyramidal configuration is assigned to zinc(II) and a dinuclear tetrahedral stereochemistry is suggested for the cadmium(II) and mercury(II) complexes on the basis of analytical, conductance, magnetic susceptibility, molecular weight, i.r., electronic, d.t.g. and d.t.a. data.     

Interactions of mercury(II), lead(II), calcium(II), aluminium(III) or ferric(III) nitrate with single and double chain linear alkylbenzenesulfonates in aqueous and sea-water media

The solubility products of mercury(II) and lead(II) dodecylbenzenesulfonates were calculated on the basis of light scattering measurements at 20°C to be (9.33 ± 0.90) × 10⁻¹³ and (1.03 ± 0.10) × 10⁻¹² respectively. The investigations of precipitation phenomena performed in diluted natural sea-water ([Cl⁻] = 10⁻¹² mol dm ⁻³), including tenside and added heavy metal ions, showed similar behaviour for all metal dodecylbenzenesulfonates investigated in this work, i.e. the synergistic effect of tenside, of added electrolyte, and of cations and anions from sea-water. A comparison made by a statistical test of significance, chosen to measure agreement between the estimates of the solubility constants obtained in aqueous solutions and in the above mentioned sea-water solution, showed a noticeable effect, evident particularly in the case of mercury(II). The precipitation of tenside and metal nitrates in natural sea-water ([Cl⁻] = 5 × 10⁻¹ mol dm⁻³) covers a wide concentration region of dodecylbenzenesulfonic acid (from high concentrations to 5 × 10⁻⁶ mol dm⁻³) and from high metal nitrate concentrations to very low. The microscopic textures of phases precipitated in the systems with sea-water obviously confirmed favouring formation of the liquid crystalline phase.     

Polymetallic complexes: Part VI. Schiff base complexes of cobalt(II), copper(II), nickel(II), zinc(II), cadmium(II) and mercury(II)

Summary The doubly bidentate ON-NO donor Schiff base, prepared from salicylaldehyde and 4,4-diaminodiphenylmethane forms complexes with 11 metal: ligand stoichiometric ratios. The cobalt(II), copper(II) and nickel(II) complexes exhibit subnormal magnetic moments. All the six complexes possess high melting points and are sparingly soluble in common organic solvents. A dinuclear octahedral structure is proposed for the cobalt(II), copper(II), nickel(II) and zinc(II) complexes and a dinuclear tetrahedral configuration is suggested for the cadmium(II) and mercury(II) complexes on the basis of analytical, conductance, magnetic susceptibility, molecular weight, i.r. and electronic spectral data.     

Sorption isotherms of Nickel(II), Cobalt(II), Mercury(II), and Lead(II) ions on a phosphorus-containing polymeric sorbent

The influence of the concentration of a complexing ion on the sorption recovery of nickel, cobalt, mercury, and lead ions from aqueous solutions by a phosphorus-containing polymeric polybutadiene-based sorbent was studied. Sorption isotherms of the studied metal ions were processed by the Langmuir and Freindlich models. The affinity of metal ions to the functional groups of a sorbent and the stability of complexes were established to decrease in the order Hg(II) > Pb(II) > Co(II) > Ni(II).     

Solution behaviour in alcohols and phase transitions of cadmium(II), mercury(II) and lead(II) carboxylates

Data were obtained for the solution behaviour of cadmium(II) and mercury(II) carboxylates in alcohols. A brief survey of the arguments about the existence of micelles and the current models of surfactant aggregation in non-aqueous media is presented. The plots of solubility against the carboxylate or alcohol chain length are linear for both cadmium and mercury soaps with the solubility having values higher in secondary than primary alcohols. The solution behaviour of metal 9, 10-dihydroxyoctadecanoates shows the effect on solubility, of substitution of dihydroxyl groups at the middle of the carbon chain. Recrystallisation temperatures of the dihydroxyoctadecanoates suggest the loss of stereochemical configuration in solution and indicate similarity in the mode of aggregation. The solution temperatures of cadmium soaps are very close to the temperatures of their phase transitions while those of mercury and lead soaps are lower than their fusion or phase transition temperatures. This behaviour is interpreted to be due to differences in the energy required for the disruption of the crystal structure which dominates the solubility mechanism.     

Aminomethylphosphines in template synthesis on Pt(II), Pd(II), and Hg(II)

Reactions of 5-p-toluidinomethyl-1,3-ditolyl-1,3,5-diazaphosphorinane 1 with Pt(II), Pd(II), Hg(II) salts are reported. Complex formation was followed by template synthesis of novel bicyclic ligand and chelate complexes. Compounds 2 , 3 , 4 have been formed. The mercury complex 4 was also obtained in high yield by electrochemical oxidation of compound 1 at the Hg-anode. Conformational features of new ligands are discussed on the basis of NMR data.     

Some Tetrahedral Coordination Polymers of Zinc(II), Cadmium(II), and Mercury(II) Involving 4-Aminomethylpyridine

Abstract

Analytical data and infrared spectral measurements down to 200 cm^?1 on the 1:1 compounds formed by the interaction of zinc(II) and cadmium(II) thiocyanates and mercury(II) chloride and bromide with 4-aminomethylpyridine indicate that the compounds are coordination polymers having tetrahedral stereochemistry with bidentate bridging 4-aminomethylpyridine molecules and terminally bonded halogen/pseudohalogen groups in the solid state.     

Simultaneous determination of cadmium(II), lead(II) and copper(II) by using a screen-printed electrode modified with mercury nano-droplets

We are presenting a strategy for the fabrication of disposable screen-printed electrodes modified with mercury nano-droplets and capable of sensing heavy metal ions. They were prepared by coating electrodes with a mixture of multi-walled carbon nanotubes and chitosan, this followed by adsorption of mercury. The resulting sensor was characterized by cyclic voltammetry and impedance spectroscopy. Also the effects caused by adsorption of mercury were investigated. It is shown that square wave anodic stripping voltammetry enables simultaneous determination of cadmium(II), lead(II) and copper(II), for which detection limits of 12, 23 and 20 nM, respectively, are found. Relative standard deviations for ten determinations at 0.6 µM concentrations of these ions are in the range of 3.0 to 5.7%. The applicability was tested by analyzing river water and showed recoveries between 94.1 and 104.6%, thus demonstrating its utility for in-field monitoring of these heavy metal ions.     

Proton-ligand and metal ligand stability constants ofN-o-chlorophenylbenzohydroxamic acids with manganese(II), nickel(II), copper(II), zinc(II), cadmium(II) and mercury(II)

Summary The thermodynamic proton-ligand and metal ligand stability constants of the newN-o-chlorophenylbenzohydroxamic acids with manganese, nickel, copper, zinc, cadmium and mercury have been determined in 1 : 1 dioxan : water at 25°.The stability of the complexes mostly follow the ligand basicity order and also the metal ion electron affinities as measured by their ionization potential. The stability constants of the metal complexes follow the order: Cu^(II) > Zn^(II) > Ni^(II) > Mn^(II) > Hg^(II) > Cd^(II).     

Catalytic amperometric and catalytic constant-current potentiometric titrations of silver(I), palladium(II) and mercury(II)

Amperometry and constant-current potentiometry were used to follow the course of catalytic titrations of silver(I), palladium(II), and mercury(II) with potassium iodide. The Ce(IV)As(III) and Ce(IV)Sb(III) systems in the presence of sulphuric acid were used as indicator reactions. The possibilities of application of platinum, palladium, gold, graphite, and glassy-carbon indicator electrodes were investigated. Graphite appeared to be somewhat more advantageous than the other electrode materials. The effect of concentration of the components of the indicator reactions, the presence of organic solvents and acids on the shape of the catalytic titration curves was studied. Amounts of 30-3000 mug of silver(I) nitrate, 90-900 mug of palladium(II) chloride, 130-1300 mug of mercury(II) chloride, and 150-1500 mug of mercury(II) nitrate were determined with a relative standard deviation less than 1.0%. The results obtained were in good agreement with those of comparable methods. The catalytic titration method developed was applied to determination of mercury in Unguentum Hydrargyri.     

Complexing behaviour of D(+)-1,2-bis(4-phenyl-1,2,4-triazoline-5-thione-3-yl)ethylene glycol with iron(III), nickel(II), copper(II), zinc(II) and mercury(II)

Summary Complexes of iron(III), nickel(II), copper(II), zinc(II) and mercury(II) with D(+)-1,2-bis(4-phenyl-1,2,4-triazoline-5-thione-3-yl)ethylene glycol have been prepared and their structures proposed on the basis of spectral studies, magnetic measurements and elemental analyses.     

Zinc(II), Cadmium(II), and Mercury(II) Complexes of 2-Methyl-benzoselenazole

The following zinc(II), cadmium(II) and mercury(II) complexes of 2-methyl-benzoselenazole (L) have been prepared and studied by conductometric and i.r. methods: MLX₂ (M ? Cd, Hg, X ? Cl, Br, I), ML_1.5X₂ (M ? Zn, X ? ClO₄(4 H₂O); M ? Hg, X ? NO₃, ClO₄), ML₂X₂ (M ? Zn, X ? Cl, Br, I, NO₃; M ? Cd, X ? NO₃, ClO₄). The ligand is N-bonded. All the anions are coordinated.     

Oxidation of Phenols and Hydroquinones by Mercury(II) Trifluoroacetate and Mercury(II) Oxide

Treatment of phenols with mercury(II) salts normally results in rapid electrophilic aromatic mercuration and formation of arylmercurial derivatives in good yield. The use of mercury(II) salts as oxidants for phenols and hydroquinones has not, however, been investigated in any detail. In 1935, Montignie reported that hydroquinone reduced mercury(II) iodide to mercury(O), but the organic reaction product was not identified.¹ A similar observation was made by Koton,² who found that reaction of hydroquinone, 4-hydroxy-aniline and pyrogallol with mercury(II) acetate did not result in mercuration but led to formation of mercury(0), while Ohno has described the “strong reducing action” of catechol and nitrohydroquinones to mercury(II) salts.³ Mercury(II) acetate has been shown to oxidise hydroquinone and 1,4-bis[β-(2,5-dihydroxyphenyl)-α-methylethylamino] anthraquinone to the corresponding quinones,^4,5 and treatment of 2,6-di-t-butyl-4-methylphenol—with mercury(II) oxide has been found to give the expected products of phenolic oxidative coupling via quinone methide formation.⁶     

Zinc(II), cadmium(II) and mercury(II) halide pyrrolidine-2-selone complexes

Summary Reaction of zinc(II), cadmium(II) and mercury(II) halides with Pyrrolidine-2-selone yields complexes of general formula ML₂X₂ (X = Cl, Br or I) which are monomeric, tetrahedral and Se-bonded to the metals. The comparison of their i.r. spectra with the spectrum of the free ligand confirms that the band at 1005 cm^–1 in Pyrrolidine-2-selone arises predominantly from the C=Se stretching vibration. The metalhalogen absorptions above 200 cm^–1 are identified.This work was supported by the National Research Council (C.N.R.) of Italy.     

Preparation and Spectral Investigation of Bis[N(2-methyl-phenyl) 4-Nitro-thiobenzamidato] mercury(II), Bis[N(2-methoxy-phenyl) 4-Nitro-thiobenzamidato]mercury(II), and Bis[N(2-chloro-phenyl) 4-Nitro-thiobenzamidato]mercury(II) Complexes

Several preparative routes to bis[N(substituted-phenyl) 4-nitro-thiobenzamidato] mercury(II) complexes are presented, including the reaction of mercury(II) oxide, fluoride, chloride, bromide, cyanide, acetate, and nitrate with N(substituted-phenyl) 4-nitro-thiobenzamide derivatives. ¹ H-NMR, Raman, and IR measurements confirmed the complexation of mercury to sulphur.     

Complexes of zinc(II), cadmium(II) and mercury(II) halides with ethylenselenourea

Summary Reaction of zinc(II), cadmium(II) and mercury(II) halides with ethylenselenourea yields complexes of general formula ML₂X₂ where X = Cl, Br, I. On the basis of an i.r. comparison of these complexes and their ethylenthiourea analogues in the 4000-200 cm^–1 range, it appears that the ethylenselenourea complexes are monomeric, tetrahedral and Se-bonded to the metals. The metal-halogen and metal-ligand vibrations above 200 cm^–1 are identified.This work was supported by the National Research Council (C.N.R.) of Italy.     

Die Extraktion und Trennung von Mikromengen Quecksilber(II), Zink(II) und Cadmium(II) mit organischen Thiophosphorverbindungen

Zusammenfassung Die Extraktion von Zink(II), Cadmium(II) und Quecksilber(II) aus salzsauren und salpetersauren Lösungen mit Di-n-butylthiophosphit und Di-n-butyl-2-hydroxypropylthiophosphonat wurde studiert. Die Abhängigkeit der Verteilung der Metalle von der Säurekonzentration und der Konzentration der Liganden wurde festgestellt. Eine neue Trennungsmethode für Mikromengen Quecksilber durch Extraktion mit Di-n-butylthiophosphit wurde entwickelt.

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The extraction and separation of micro amounts of Hg(II) from Zn(II) and Cd(II) by means of thiophosphoric compounds

Summary The extraction of zinc(II), cadmium(II) and mercury(II) from hydrochloric and nitric acid solutions has been studied with di-n-butyl thiophosphite and di-n-butyl 2-hydroxypropyl thiophosphonate. The dependence of the extraction of the metals on the acid and ligand concentrations has been established. A new separation method for micro amounts of mercury has been developed.

     

Salisaldehyde-2-aminobenzimidazole schiff base complexes of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)

New metal complexes of Fe(III), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with salicylidine-2-aminobenzimidazole (SABI) are synthesized and their physicochemical properties are investigated using elemental and thermal analyses, IR, conductometric, solid reflectance and magnetic susceptibility measurements. The base reacts with these metal ions to give 1:1 (Metal:SABI) complexes; in cases of Fe(III), Co(II), Cu(II), Zn(II) and Cd(II) ions; and 1:2 (Metal:SABI) complexes; in case of Ni(II) ion. The conductance data reveal that Fe(III) complex is 2:1 electrolyte, Co(II) is 1:2 electrolyte, Cu(II), Zn(II) and Cd(II) complexes are 1:1 electrolytes while Ni(II) is non-electrolyte. IR spectra showed that the ligand is coordinated to the metal ions in a terdentate mannar with O, N, N donor sites of the phenloic -OH, azomethine -N and benzimidazole -N3. Magnetic and solid reflectance spectra are used to infer the coordinating capacity of the ligand and the geometrical structure of these complexes. The thermal decomposition of the complexes is studied and indicates that not only the coordinated and/or crystallization water is lost but also that the decomposition of the ligand from the complexes is necessary to interpret the successive mass loss. Different thermodynamic activation parameters are also reported, using Coats-Redfern method. This revised version was published online in July 2006 with corrections to the Cover Date.     

Redox magnetohydrodynamics enhancement of stripping voltammetry of lead(II), cadmium(II) and zinc(II) ions using 1,4-benzoquinone as an alternative pumping species

Differential pulse anodic stripping voltammetry (DPASV) coupled with redox-magnetohydrodynamics (MHD) is used to enhance the anodic stripping voltammetry (ASV) response using a mercury thin film-glassy carbon electrode. The sensitivity increased to at least a factor of two (at 1.2 T) and is facilitated by using 20.0 mmol L(-1) 1,4-benzoquinone as an alternative pumping species to enhance ASV by redox-MHD. The MHD force formed by the cross-product of ion flux with magnetic field induces solution convection during the deposition step, enhancing mass transport of the analytes to the electrode surface and increasing their preconcentrated quantity in the mercury thin film. Therefore, larger ASV peaks and improved sensitivities are obtained, compared with analyses performed without a magnet. The influence of pH, 1,4-benzoquinone concentration, accumulation potential, and time are also investigated. Detection limits of 0.05, 0.09 and 2.2 ng mL(-1) Cd(II), Pb(II) and Zn(II) were established with an accumulation time of 65 s. The method is used for the analysis of Cd(II), Pb(II) and Zn(II) in different water samples, certified reference materials, and saliva samples with satisfactory results.     

Synthesis of norfloxacin compounds with cobalt(II), zinc(II), cadmium(II), and mercury(II)

New compounds of norfloxacin (nfH, C₁₆H₁₈FN₃O₃) with cobalt(II), zinc(II), cadmium(II), and mercury(II) synthesized have the following compositions: Co(nfH-O,O’)₂(H₂O)₂](NO₃)₂, (nfH₂)₂CdCl₄ · 2H₂O, (nfH₂)₂ZnCl₄ · 2H₂O, (nfH₂)₂HgCl₄ · 2H₂O, and (nfH₃)HgCl₄. Their crystallographic parameters were determined. The first listed compound is isostructural to the known zinc analogue. Norfloxacin coordination modes in these complexes are considered.