Electrophilic Copper(II) → Metal(II) Substitution in Gelatin-Immobilized Copper(II) Hexacyanoferrate(II) Matrix Implants

Contact of thin layers of gelatin-immobilized copper(II) hexacyanoferrate(II) matrices with aqueous solutions of Co(II), Ni(II), Zn(II), and Cd(II) chlorides results in partial substitution of these ions for Cu(II) to give (dd)-heterobinuclear hexacyanoferrates(II) of copper(II) and the corresponding double-charged ion.     

Polydentate N(2)S(2)O and N(2)S(2)O(2) Ligands as Alcoholic Derivatives of (N,N'-Bis(2-mercaptoethyl)-1,5-diazacyclooctane)nickel(II) and (N,N'-Bis(2-mercapto-2-methylpropane)-1,5-diazacyclooctane)nickel(II)

The synthesis, structural characterization, spectroscopic, and electrochemical properties of N(2)S(2)-ligated Ni(II) complexes, (N,N'-bis(2-mercaptoethyl)-1,5-diazacyclooctane)nickel(II), (bme-daco)Ni(II), and (N,N'-bis(2-mercapto-2-methylpropane)1,5-diazacyclooctane)nickel(II), (bme-daco)Ni(II), derivatized at S with alcohol-containing alkyl functionalities, are described. Reaction of (bme-daco)Ni(II) with 2-iodoethanol afforded isomers, (N,N'-bis(5-hydroxy-3-thiapentyl)-1,5-diazacyclooctane-O,N,N',S,S')halonickel(II) iodide (halo = chloro or iodo), 1, and (N,N'-bis(5-hydroxy-3-thiapentyl)-1,5-diazacyclooctane-N,N',S,S')nickel(II) iodide, 2, which differ in the utilization of binding sites in a potentially hexadentate N(2)S(2)O(2) ligand. Blue complex 1 contains nickel in an octahedral environment of N(2)S(2)OX donors; X is best modeled as Cl. It crystallizes in the monoclinic space group P2(1)/n with a = 12.580(6) ?, b = 12.291(6) ?, c = 13.090(7) ?, beta = 97.36(4) degrees, and Z = 4. In contrast, red complex 2 binds only the N(2)S(2) donor set forming a square planar nickel complex, leaving both -CH(2)CH(2)OH arms dangling; the iodide ions serve strictly as counterions. 2 crystallizes in the orthorhombic space group Pca2(1) with a = 15.822(2) ?, b = 13.171(2) ?, c = 10.0390(10) ?, and Z = 4. Reaction of (bme-daco)Ni(II) with 1,3-dibromo-2-propanol affords another octahedral Ni species with a N(2)S(2)OBr donor set, ((5-hydroxy-3,7-dithianonadiyl)-1,5-diazacyclooctane-O,N,N',S,S')bromonickel(II) bromide, 3. Complex 3 crystallizes in the orthorhombic space group Pca2(1) with a = 15.202(5) ?, b = 7.735(2) ?, c = 15.443(4) ?, and Z = 4. Complex 4.2CH(3)CN was synthesized from the reaction of (bme-daco)Ni(II) with 1,3-dibromo-2-propanol. It crystallizes in the monoclinic space group P2/c with a = 20.348(5) ?, b = 6.5120(1) ?, c = 20.548(5) ?, and Z = 4.     

Determination of components of the Cd(II)-Pb(II)-Cu(II) system in aqueous solutions of (polyethylene imine)methylthiourea by stripping voltammetry

Conditions were studied for the stripping voltammetric determination of components of the Cd(II)-Pb(II)-Cu(II) system in aqueous solutions of (polyethylene imine)methylthiourea (PMT), the most efficient polymer complexant for the membrane preconcentration of heavy metal ions. It was shown that PMT significantly enhances the selectivity of determining Pb(II) and Cd(II) in solutions of Cu(II) by stripping voltammetry. Pb(II) and Cd(II) can be determined in the presence of up to 200- and 50-fold amounts of Cu(II), respectively. The limits of detection for Pb(II) and Cd(II) after a 40-s accumulation were 6.9 x 10^-8 and 6.8 x 10^-7 M, respectively.     

Application of zone-melting technique to metal chelate systems-X Zone-refining of bis(acetylacetonato)beryllium(II), tris(acetylacetonato)aluminium(III) and bis(di-isovalerylmethanato)copper(II)

Bis(acetylacetonato)beryllium(II), tris(acetylacetonato)aluminium(III) and bis(di-isovaleryl-methanato)copper(II) were zone-refined. Also crude beryllium(II), aluminium(III) and copper(II) salts were purified by zone-melting the above-mentioned chelates, obtained by precipitation from aqueous methanol solutions. Some contaminants were excluded at the stage of chelate formation and the remainder were concentrated at the terminal end of a zone-refining column.     

Solid-phase extraction and preconcentration of cadmium(II) in aqueous solution with Cd(II)-imprinted resin (poly-Cd(II)-DAAB-VP) packed columns

A novel chelating resin (poly-Cd(II)-DAAB-VP) was prepared by metal ion imprinted polymer (MIIP) technique. The resin was obtained by one pot reaction of Cd(II)-diazoaminobenzene-vinylpyridine with cross-linker ethyleneglycoldimethacrylate (EGDMA). Comparing with non-imprinted resin, the poly-Cd(II)-DAAB-VP has higher adsorption capacity and selectivity for Cd(II). The distribution ratio (D) values for the Cd(II)-imprinted resin show increase for Cd(II) with respect to both D values of Zn(II), Cu(II), Hg(II) and non-imprinted resin. The relatively selective factor (α_r) values of Cd(II)/Cu(II), Cd(II)/Zn(II) and Cd(II)/Hg(II), are 51.2, 45.6, and 85.4, which are greater than 1. poly-Cd(II)-DAAB-VP can be used at least 20 times without considerable loss of adsorption capacity. Based on poly-Cd(II)-DAAB-VP packed columns, a highly selective solid-phase extraction (SPE) and preconcentration method for Cd(II) from aqueous solution was developed. The MIIP-SPE preconcentration procedure showed a linear calibration curve within concentration range from 0.093 to 30 μg l⁻¹. The detection limit and quantification limit were 0.093 and 0.21 μg l⁻¹ (3σ) for flame atomic absorption spectrometry (FAAS). The relative standard deviation of the eleven replicate determinations was 3.7% for the determination of 10 μg of Cd(II) in 100 ml water sample. Determination of Cd(II) in certified river sediment sample (GBW 08301) demonstrated that the interfering matrix had been almost removed during preconcentration. The column was good enough for Cd(II) determination in matrixes containing components with similar chemical property such as Cu(II), Zn(II) and Hg(II).     

Kinetic effect of zinc(II) and cadmium(II) ions on configurational inversion of deltaLLL-fac(S)-tris(L-cysteinato-N,S)cobalt(III) complex.

It has been confirmed from circular dichroism (CD) spectral changes of aqueous solutions of deltaLLL-fac(S)-[Co(L-cys-N,S)3]3- that the absolute configurational inversion to the ALLL isomer is remarkably accelerated by zinc(II), while it is retarded by cadmium(II). In the diluted solutions of these metal ions containing excess deltaLLL-fac(S)-[Co(L-cys-N,S)3]3-, the observed inversion rate constant linearly depends on the zinc(II) concentration with an intercept, while it is not affected by the cadmium(II) concentration. The kinetic behavior has been explained by difference between zinc(II)- and cadmium(II)-interactions with lone pairs on sulfur donor atoms of fac(S)-[Co(L-cys-N,S)3]3-. It has also been proposed that concentrations of zinc(II) and cadmium(II) can be simultaneously determined by the kinetic measurements.     

Reactions of octacyanomolybdate(V) and octacyanotungstate(V) with s(2) metal-ion reducing centers

The s(2) centers, Sn(II), Ge(II), and In(i) reduce Mo(V)(CN)(8)(3-) and W(V)(CN)(8)(3-) quantitatively to the corresponding octacyanomolybdate(IV) and -tungstate(iv) anions. Reductions by In(i) proceed 10(3)-10(5) times as rapidly as those by Sn(II) and Ge(II). All reactions are triggered by a single electron oxidation, yielding a much more reactive s(1) intermediate. Reductions by Sn(II) in chloride medium proceed predominantly through the SnCl(3)(-) anion. The Ge(II)-W(CN)(8)(3-) reaction is initiated by a slow unimolecular heterolysis of the Ge(II) center, yielding very nearly linear profiles when the reductant is in excess.     

Copper(II) and nickel(II) complexes of binucleating macrocyclic bis(disulfide)tetramine ligands

Novel macrocyclic bis(disulfide)tetramine ligands and several Cu(II) and Ni(II) complexes of them with additional ligands have been synthesized by the oxidative coupling of linear tetradentate N2S2 tetramines with iodine. Facile demetalation of the Ni(II) oxidation products affords the free 20-membered macrocycles meso-9 and rac-9 and the 22-membered macrocycle 16, all of which are potentially octadentate N4S4 ligands. X-ray structure analyses reveal distinctly different conformations for the two isomers of 9; meso-9 shows a stepped conformation in profile with the disulfide groups corresponding to the rise of the step, whereas rac-9 exhibits a V conformation with the disulfide groups near the vertex of the V. No metal complexes of rac-9 have been isolated. Crystallographic studies of three Cu(II) complexes reveal that depending upon the size of the macrocyclic ligand and the nature of the additional ligands (I-, NCO-, and CH3CN), the Cu(II) coordination geometry shows considerable variation (plasticity), with substantial changes in the Cu(II)-disulfide bonding. Thus, a diiodide salt contains six-coordinate Cu(II) to which all four bridging disulfide sulfur atoms form strong equatorial bonds. In contrast, isocyanato complexes of the 20- and 22-membered macrocycles exhibit trigonal-bipyramidal Cu(II) and distorted cis-octahedral Cu(II) geometries, respectively, having only one and no short equatorially bound sulfur atoms. The coordination geometry of the latter complex can also be described as four-coordinate seesaw with two semicoordinated S(disulfide) ligands. Disulfide-->Cu(II) ligand-to-metal charge transfer absorptions of both isocyanato-containing Cu(II) species appear too weak to observe, probably because of poor overlap of the sulfur orbitals with the Cu(II) d-vacancy. The dual disulfide-bridged Ni(II) units of the crystallographically characterized octahedral Ni(II) complex of meso-9 with axial iodide and acetonitrile ligands promote substantial antiferromagnetic coupling (J = -13.0(2) cm-1).     

Spectrophotometric Studies of Nickel(II) and Copper(II) Chelates of p-(2-Hydroxy-1-Naphthylazo)-Benzenesulphonate

The ionization constant of p-(2-hydroxy-1-naphthylazo)benzene-sulphonate (Orange II) and the formation constants of the metal chelates of this reagent with Ni(II) and Cu(II) have been determined spectrophotometrically in aqueous solution at 25° and at an ionic strength of 0.10M. The ionization constant of orange II was found to be pK_a=10.95. Formation of orange II chelates with Ni(II) and Cu(II) was pH dependent, and the optimum pH range of the Ni(II) Chelate was at pH 9.2-9.4, and Cu(II) chelate at 9.5-9.7, respectively. The mole ratio of orange II to both of metal ions was found to be 2 to 1 stoichiometry. The formation constants (logK) of the Ni(II) and Cu(II) chelates were 12.50 and 16.11, respectively. The molar extinction coefficients and the photometric sensitivities of these chelates were determined.     

Acidites et complexes des acides (alkyl-et aminoalkyl-) phosphoniques-IV: acides aminoalkylphosphoniques R(1)R(2)N(CH(2))(n)CR(3)R(4)PO(3)H(2)

The acids under study differed from one another in length of the carbon chain [N + H(3)(CH(2))(n)PO(3)H(-) for n = 1, 2, 3], substitution on the nitrogen atom [R(1)R(2)N + HCH(2)PO(3)H(-) for R(1) = H; R(2) = Me, Et and R(1) = R(2)= Me, Et] or extent of branching on the carbon atom adjacent to functional groups [N + H(3)CR(3)R(4)PO(3)H(-) for R(3) = H; R(4) = Me, Et, nPr, iPr, nBu and R(3) = R(4) = Me]. Acidity constants and overall stability constants of complexes formed with Ca(II), Mg(II), Co(II), Ni(II), Cu(II), Zn(II) were obtained with the multiparametric refinement programs MUPROT and MUCOMP, applied to potentiometric data, obtained at 25 degrees , in a 0.1M potassium nitrate medium. In the most general case, the existing species are MHA(+), MA, M(OH)A(-), MH(2)A(2), MHA(-)(2) and MA(2-)(2), where A(2-) stands for the fully ionized ligand; preliminary examination of results points out some predominant microscopic forms.     

Adsorption of zinc(II) and copper(II) to Shirasu (pyroclastic flow)

A fundamental study on the adsorption of metal elements on Shirasu, a pyroclastic flow deposit distributed in southern Kyushu, Japan, has been conducted. The adsorption experiment was carried out by a batch method, and by using Zn(II) and Cu(II) under several conditions; the effects of the initial concentration of metal ions, grain size, and pH were investigated. At smaller grain sizes, the amount of Zn(II) and Cu(II) adsorbed increased. At higher pH values, the amount of Zn(II) and Cu(II) adsorbed increased. Plots of the adsorption isotherm indicated that the adsorption of Zn(II) and Cu(II) on Shirasu followed the Langmuir isotherm model, and the Langmuir isotherm constants, W(0) and b, were obtained. W(0) at pH 5.0 was approximately two-times larger than that at pH 3.0. This may reflect an increase in the number of anionic binding sites on the surface of Shirasu with an increase in the pH. The b value for Zn hardly changed with an increase in the pH, and for Cu the value decreased with an increase in the pH. These observations suggest that anionic binding sites have a low stability constant, since the apparent stability constant, b, is obtained as the average of stability constant of all sites on the Shirasu surface.     

Copper(II) and copper(III) complexes of pyrrole-appended oxacarbaporphyrin

The reaction of an O-confused porphyrin with a pendant pyrrole 4 and copper(II) acetate yields an organocopper(III) diamagnetic complex 4-Cu(III) substituted at the C(3) position by the pyrrole and H. The transformation of 4-Cu(III), performed in aerobic conditions, gave a rare copper(II) organometallic compound 6-Cu(II). In the course of this process, the tetrahedral-trigonal rearrangement originated at the C(3) atom but effects the whole structure. The electron paramagnetic resonance spectroscopic features correspond to a copper(II) oxidation state. A crystallographic analysis of 6-Cu(II) confirmed the formation of a direct metal-C bond [Cu(II)-C 1.939(4) A]. It was found that the Cu(II) complex of O-confused oxaporphyrin is sensitive to oxidative conditions. The degradation of 6-Cu(II) to yield copper(II) tripyrrinone complexes has been observed, which was considered as a peculiar case of dioxygen activation in a porphyrin-like environment. This process is accompanied by regioselective oxygenation at the inner C to form the 2-oxa-3-(2'-pyrrolyl)-21-hydroxycarbaporphyrinatocopper(II) complex ((pyrr)OCPO)CuII (8). The reaction of 6-Cu(II) with hydrogen peroxide, performed under heterophasic conditions, resulted in quantitative regioselective hydroxylation centered at the internal C(21) atom, also producing 8. Treatment of 8 with acid results in demetalation to form the nonaromatic 21-hydroxy O-confused porphyrin derivative ((pyrr)OCPOH)H (9).     

Micro volume changes due to Pb(II) and Cu(II) sorption on amorphous Fe(III) hydroxide

Micro volume changes due to Pb(II) and Cu(II) sorption on amorphous Fe(III) hydroxide (AFH) were determined by a dilatometer at pH 4.50. Volume change is attributed to change in hydration status of dissolved and/or suspended substances. The volume of the system increased due to Pb(II) and Cu(II) sorption, suggesting that water molecules hydrated around Pb(II) or Cu(II) ions and AFH were released during sorption. Volume increases due to Pb(II) and Cu(II) sorption were smaller than those due to bulk precipitation of Pb and Cu hydroxides. Precipitation of Pb(II) and Cu(II) was not likely to occur at pH 4.50 in the presence of AFH. In conclusion, Pb(II) and Cu(II) formed an inner-sphere complex on AFH at pH 4.50, keeping hydrated water on the adsorbed species. Adsorbed Cu(II) kept more hydrated water than adsorbed Pb(II) on AFH.     

Isomorphous replacement of M(II) ions in M(II)-Gd(III) dimers (M(II) = Cu(II), Mn(II), Ni(II), Co(II), Zn(II)): magnetic studies of the products

Complexes [M(II)Gd(III){pyCO(OEt)pyC(OH)(OEt)py}?](ClO?)?·EtOH [M(II) = Cu(II) (1), Mn(II) (2), Ni(II) (3), Co(II) (4) and Zn(II) (5)] crystallize in the monoclinic Cc space group and contain one hexacoordinate M(II) ion and one enneacoordinate Gd(III) ion, bridged by three {pyCO(OEt)pyC(OH)(OEt)py}? ligands. Magnetic susceptibility measurements indicate a ferromagnetic interaction for 1 and antiferromagnetic interactions for 2-4. Using the ? = -J?(Gd(III))?(M(II)) spin Hamiltonian formalism, fits to the magnetic susceptibility data yielded J values of +0.32 cm?1 for 1, -1.7 cm?1 for 2, and -0.22 cm?1 for 3. In complex 4, the orbital contributions of Co(II) precluded the determination of the magnetic coupling. The complex follows the Curie-Weiss law with θ = -2.07 K (-1.44 cm?1).     

Removal of As(V) by Cu(II)-, Ni(II)-, or Co(II)-doped goethite samples

The present study reports removal of As(V) by adsorption onto laboratory-prepared pure and Cu(II)-, Ni(II)-, and Co(II)-doped goethite samples. The X-ray diffraction patterns showed only goethite as the crystalline phase. Doping of ions in the goethite matrix resulted in shift of d-values. Various parameters chosen for adsorption were nature of adsorbent, percentage of doped cations in goethite matrix, contact time, solution pH, and percentage of adsorbate. It was observed that the pH(pzc) of the goethite surface depended on the nature and concentration of metal ions. The surface area as well as the loading capacity increased with the increase of dopant percentage in goethite matrix. A maximum loading capacity of 19.55 mg/g was observed for 2.7% Cu(II)-doped goethite. The adsorption kinetics for Ni(II), Co(II) and for undoped goethite attained a quasi-equilibrium state after 30 min with almost negligible adsorption beyond this time. In case of Cu(II)-doped goethite samples, the quasi-equilibrium state for As(V) adsorption was observed after 60 min. At each studied pH condition, it was observed that the percentage of adsorption of As(V) decreased in the order Cu(II)-doped goethite > or = Ni(II)-doped goethite > Co(II)-doped goethite > pure goethite. The adsorption followed: Langmuir isotherm, indicating monolayer formation.     

Spectrophotometric Determination of Cobalt(II), Nickel(II) and Copper(II) with Acenaphthenequinone Monosemicarbazone (AQSC)

Cobalt(II), nickel(II) and copper(II) complexation with acenaphthenequinone monosemicarbazone (AQSC) has been studied spectrophotometrically. The Co(II), Ni(II) and Cu(II) complexes are soluble in ethanol medium and exhibit maximum absorbance at 410, 420 and 430 nm, respectively. The sensitivity of the reactions are 0.012, 0.02 and 0.01 μg/cm² for cobalt, nickel and copper systems. All the three complexes show maximum and constant absorbance in the pH range 8.4 to 9.8, 6.3 to 8.4 and 5.4 to 8.0 for Co-AQSC, Ni-AQSC and Cu-AQSC, respectively. Nickel and copper in some alloys have also been analysed.     

Transmetalation of (octaphenyltetraazaporphyrinato)magnesium(II) with manganese(II) chloride in dimethylformamide

The reaction of (octaphenyltetraazaporphyrinato)magnesium(II) with manganese(II) chloride in dimethylformamide gave (chloro)(octaphenyltetraazaporphyrinato)manganese(III). Reactions of the latter with nitrogen-containing bases were studied. The kinetic parameters of the transmetalation of (octaphenyltetraazaporphyrinato) magnesium(II) with MnCl₂ in dimethylformamide at 323, 333, and 343 K were determined, and a probable reaction mechanism was proposed.     

环戊基(苯)膦-镍系配合物的可见-紫外光谱及其空间构型

测定了环戊基(苯)膦-镍(II), 钯(II)和铂(II)十五种配合物的可见-紫外光谱, 并参照各吸收谱带的归宿, 推断了配合物的空间构型及其在溶液中的构型异构化现象.     

Thermal decomposition of trans-chloro(2-allylphenyl)bis(triethylphospine)nickel(II)

Thermolysis of trans-chloro(2-allylphenyl)bis(triethylphosphine)nickel(II), I, in tetrachloroethylene has afforded indene as the major hydrocarbon product along with lesser amounts of allylbenzene and trans-β-methylstyrene. Organonickel products were trans-chloro(trichlorovinyl)bis(triethylphosphine)nickel(II), II, chloro[2-(trans-propenyl)phenyl]bis(triethylphosphine)nickel(II), III, and trans-dichlorobis(triethylphosphine)nickel(II). Compound III was the major product from thermolysis of I in benzene. Chloro[2-(cis-propenyl)phenyl]bis(triethylphosphine)nickel(II), IV, and III could be synthesized independently by treatment of chloro-2-(cis-propenyl)benzene and chloro-2-(trans-propenyl)benzene, respectively, with nickel acetylacetonate and triethylaluminium in the presence of triethylphosphine. Thermolysis of I in benzene containing allylbenzene led to the formation of trans-β-methylstyrene. The thermolysis of I in benzene in the presence of cis-1,4-hexadiene caused the skeletal rearrangement of the diene to trans-2-methyl-1,3-pentadiene. A catalyst derived from ethylenebis(triphenylphosphine)nickel(0) and hydrogen chloride isomerized allylbenzene to trans-β-methylstyrene.     

Thermal decomposition of Co(II), Ni(II), Cu(II) and Zn(II) hippurates

The hippurates of Co(II), Ni(II), Cu(II) and Zn(II) were isolated from the solution, their quantitative composition and the way of coordination of metal — ligand were determined and the conditions and products of thermal decomposition during heating in air atmosphere up to 1273 K were studied. The complexes of Ni(II), Cu(II) and Zn(II) heated lose some water molecules and then decompose to MO. The hippurate of Co(II) heated loses some water molecules and then decomposes to CoO with intermediate formation Co₃O₄.

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Zusammenfassung Aus Lösung wurden die Co(II)-, Ni(II)-, Cu(II)- und Zn(II)-Salze der Hippursäure gewonnen, ihre quantitative Zusammensetzung sowie die Art der Koordination der Metall-Ligandenbindung bestimmt. Weiterhin wurden die Bedingungen und Produkte der thermischen Zersetzung beim Erhitzen in einer Luftatmosphäre bis 1273 K untersucht. Die Komplexe von Ni(II), Cu(II) und Zn(II) verlieren beim Erhitzen ein paar Moleküle Wasser und zersetzen sich anschlieend zu MO. Co(II)-hippurat gibt beim Erhitzen einige Moleküle Wasser ab und zersetzt sich dann über die Zwischenstufe Co₃O₄ zu CoO.