Stability constants of Zn(II), Pb(II), Cd(II) and Cu(II) complexes with hematoxylin

The composition and stability constants of the complexes of Zn(II), Pb(II), Cd(II) and Cu(II) with hematoxylin have been studied using direct current polarography and differential pulse polarography. The results showed the formation of 1:2 (M:L) complexes for Zn(II) and Pb(II), and a 1:6 (M:L) complex for Cd(II). However, the formation of copper-hematoxylin complex is irreversible. The values of the formation constants for the above complexes at 298, 308 and 318K were calculated as well as the relevant thermodynamic parameters.     

Anti-inflammatory drugs interacting with Zn(II), Cd(II) and Pt(II) metal ions

Complexes of Zn(II), Cd(II) and Pt(II) metal ions with the anti-inflammatory drugs, 1-methyl-5-(p-toluoyl)-1H-pyrrole-2-acetic acid (Tolmetin), alpha-methyl-4-(2-methylpropyl)benzeneacetic acid (Ibuprofen), 6-methoxy-alpha-methylnaphthalene-2-acetic acid (Naproxen) and 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid (indomethacin) have been synthesized and characterized. In the structurally characterized Cd(naproxen)2 complex the anti-inflammatory drugs acts as bidentate chelate ligand coordinatively bound to metal ions through the deprotonated carboxylate group. Crystal data for 1: [C32H26O8Cd], orthorhombic, space group P22(1)2(1), a = 5.693(2) (A), b = 8.760(3) (A), c = 30.74(1) (A), V = 1533(1) A3, Z = 2. Antibacterial and growth inhibitory activity is higher than that of the parent ligands or the platinum(II) diamine compounds.     

The kinetics of the solvent extraction of cobalt (II) and lead (II) with versatic acid

In the solvent extraction of cobalt (II) and lead (II) from aqueous ammonium nitrate solutions with Versatic 10 in hexane, initial extraction rates were measured at 303 K using a Lewis-type stirred transfer cell. In the extraction of cobalt(II), the initial extraction rate expression was found to be described by N = κ₁C_AW/[H⁺] in the high concentration region of Versatic 10 and by N = κ_IIC_AWC_BO²/[H⁺]² in the low concentration region of Versatic 10. An interfacial reaction mechanism was proposed in order to give a reasonable interpretation of the observed rate expressions. In the extraction of lead(II), the initial extraction rate at low pH was found to be described also by the second rate expression shown above. At high pH, the rate is independent of hydrogen ion concentration. From this result, it was presumed that only the non-hydrated aquo-cation of lead(II) takes part in complex formation at the interface.     

Oxygen equilibrium properties of asymmetric nickel(II)-iron(II) hybrid hemoglobin

Asymmetric Ni(II)-Fe(II) hybrid hemoglobin, XL[alpha(Fe)beta(Fe)][alpha(Ni)beta(Ni)], in which the alpha 1 beta 1 dimer containing ferrous protoporphyrin IX and the complementary alpha 2 beta 2 dimer containing Ni(II) protoporphyrin IX were cross-linked between Lys-82 beta 1 and Lys-82 beta 2 by reaction with bis(3,5-dibromosalicyl) fumarate, was synthesized and characterized. We have previously shown that (i) Ni(II) protoporphyrin IX, which binds neither oxygen nor carbon monoxide, mimics a fixed deoxyheme with respect to its effect on the oxygen equilibrium properties of the counterpart iron subunits in both symmetric Ni(II)-Fe(II) hybrid Hbs [Shibayama, N., Morimoto, H., & Miyazaki, G. (1986) J. Mol. Biol. 192, 323-329] and (ii) the cross-linking used in this study little affects the oxygen equilibrium properties of hemoglobin [Shibayama, N., Imai, K., Hirata, H., Hiraiwa, H., Morimoto, H., & Saigo, S. (1991) Biochemistry 30, 8158-8165]. These remarkable features of our model allowed us to measure the oxygen equilibrium curves for the first two steps of oxygen binding to the alpha 1 beta 1 dimer within the hemoglobin tetramer. At all pH values examined, the affinities of this asymmetric hybrid for the first oxygen molecule are as low as those of native hemoglobin. The hybrid did not show cooperative oxygen binding at pH 6.4, while significant cooperativity was observed with rising pH; i.e., the Hill coefficient was increased from 1.41 to 1.53 upon a pH change from 7.4 to 8.4. The electronic absorption spectrum of Ni(II) protoporphyrin IX in the alpha 2 subunit was changed upon carbon monoxide (or oxygen) binding to the alpha 1 beta 1 dimer.(ABSTRACT TRUNCATED AT 250 WORDS)     

Preconcentration of Pb(II), Cd(II), Cu(II) and Hg(II) with 2-mercapto-5-phenylamino-1,3,4-thiadiazole impregnated on silica gel

Silica gel modified by the addition of 2-mercapto-5-phenylamino-1,3,4-thiadiazole (MPATD) was developed for the preconcentration of Pb(II), Cd(II), Cu(II) and Hg(II) at trace levels. A "series" experimental procedure permitted the determination of the optimal working conditions (time and pH) and an "on-column" experimental method permitted the determination of the quantity of MPATD retained on silica gel, the uptake capacity, the most suitable eluent and the minimum volume of eluent for which the maximum quantity of metal cations is recovered. The maximal retention capacity on the impregnated silica gel columns was obtained at pH 7.5-8 and was 1500 micrograms g-1 for Pb(II) and about 1000 micrograms g-1 for Cd(II), Cu(II) and Hg(II). The effect of preconcentration is relevant; on passing 1 l of solution containing 1 microgram ml-1 of cation through a column containing 5 g of impregnated silicagel, after elution with 30-50 ml of the appropriate eluent the cation concentration increased about 15-20-fold. The determination of cations by flame AAS was statistically evaluated and showed recoveries higher than 96% for Pb(II), 98.5% for Cd(II) and 97.95% for Cu(II) after elution with 4 M HNO3 and about 99.15% for Hg(II) after elution with thiourea.     

Investigation of Cobalt (II)-Tungsten (Vl)-Oxide Reduction in Hydrogen: Part II

CoWO₄ monocrystals were prepared by the flux growth method and their reduction in pure hydrogen was investigated for comparison with that of powdery specimen S1 (Part I). Here again phaseϕ is observed, besideβ-W, as a low temperature reaction product (from which cph-Co₃W alloy crystallizes at higher temperatures). Present results tend to show that ϕ can most logically be regarded as a noncrystalline alloy with defined composition Co 25 at. pct W(i.e. Co₃W), similar to that whose characteristics and electrodeposition conditions are reported in the literature.     

Über die Kinetik der Reaktion von Eisen(II)-, Nickel(II)-und Kobalt(II)-oxyd mit Graphit

An plattenförmigen Proben aus Eisen(II)-, Nickel(II)- und Kobalt(II)-oxyd sowie an feinkörnigen Eisen(II)-oxydproben Untersuchung der Kinetik der Reaktion mit Graphit bei Temperaturen zwischen 920 und 1200 °C durch Messung der Gewichtsabnahme der Probe und des durch die Reaktion gebildeten Kohlendioxyds. Erörterung der Reaktionsmechanismen.     

Co(Ⅱ)在NH_3-NH_4Cl-H_2O体系中的平衡规律

利用双平衡法,研究了Co(Ⅱ)-NH3-Cl--H2O体系中Co?的溶解规律,通过计算绘制了热力学平衡图,揭示了体系中各物质的平衡浓度与氨水浓度和氯离子浓度之间的关系。结果表明,在该体系中唯一存在的固相物质为Co(OH)2(S),试验验证了热力学计算结果,两者之间的偏差仅为10.13%。     

Synthesis,characterization and biological studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes involving a potentially tetradentate Schiff base ligand

Co(II), Ni(II), Cu(II) and Zn(II) complexes of the Schiff base derived from vanillinidene-4-aminoantipyrine and o-phenylenediamine were synthesized and characterized by elemental analysis, ¹H-NMR, ¹³C-NMR, molar conductance, infrared, electronic, magnetic measurements, cyclic voltammetry, powder XRD and SEM. The IR results demonstrate that the co-ordination sites are the four azomethine nitrogen atoms. The electronic spectral and magnetic measurement data indicate that the complexes exhibit octahedral geometry. Powder XRD displays the crystalline nature of Co(II) and Zn(II) complexes. The SEM images reveal that all the complexes have almost similar morphologies with broken-stone like structure. The in vitro biological screening effects of the synthesized compounds were tested against the bacterial species, Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa and Staphylococcus aureus; fungal species, Aspergillus niger, Aspergillus flavus and Candida albicans by the disc diffusion method and the results show that the metal complexes are more biological active than the ligand.     

A solvent extraction study of silver(I), palladium(II) and mercury(II) with 2-tert-dodecylthiopyridine

2-tert-Dodecylthiopyridine was synthesized from 2-chloropyridine and tert-dodecanethiol in order to examine its extraction properties for various metals. It was found to have good selectivity for the extraction of palladium(II) and mercury(II) over platinum(II) and -(IV) and base metals from chloride media; silver(I) was found to be almost completely extracted from nitric acid (0.01–5 mol/dm³ HNO₃). Palladium(II) and mercury(II) were completely extracted from hydrochloric acid over the range 0.01–2 and 0.01–0.5 mol/dm³ HCl, respectively. The rate of extraction of palladium(II) from hydrochloric acid was much faster than when using dialkylsulfide and triisobutylphosphine sulfide extractants. An aqueous mixture of thiourea and hydrochloric acid was found to be effective as stripping solution for palladium(II). The extent of stripping was dependent on the concentrations of either thiourea or hydrochloric acid.     

Direct Spectroscopic Determination of Europium（ Ⅱ ） Concentration During Europium（ Ⅲ ） Electro-Reduction in Hydrochloric Acid Medium

Europiumis one of the most important rare earth(RE) element .It is widely used as a component ofcathode ray tubes , with screen coated with red phos-phor ,as phosphorescent pigments ,andinlaser optics .It can also be used as neutron-absorbing material .In…     

The coprecipitation behavior of Co(II) and Ni(II) with Fe(III), Cr(III) and Al(III) from aqueous ammoniacal solutions

The coprecipitation of cobalt(II) and nickel(II) with iron(III), chromium(III) and aluminum(III) from ammoniacal solutions has been investigated. The coprecipitation behavior was found to be very sensitive to the solution pH and total ammonia concentration. Co(II) and Ni(II) can be precipitated from low ammonia concentration solutions but are readily redissolved at higher ammonia concentrations. The coprecipitate of divalent and trivalent species was found to contain very large amounts of the divalent metals (up to a mole ratio M M(II)/M(III) of 2.5) when aluminum was the trivalent species, whereas with iron(III) or chromium(III), the ratio was only 0.5.     

Resonance Raman spectra of iron(III)-, copper(II)-, cobalt(III)-, and manganese(III)-transferrins and of bis(2,4,6-trichlorophenolato)diimidazolecopper(II) monohydrate, a possible model for copper(II) binding to transferrins

Fe(III), Cu(II), Co(III), and Mn(III) complexes of ovo- and human serum transferrins show resonance enhanced Raman bands near 1600, 1500, 1270, and 1170 cm-1 upon excitation with laser frequencies which fall within the visible absorption bands of those metalloproteins. Comparison of the visible absorption and resonance Raman spectra of the Cu(II)-transferrin complexes with those for the Cu(II) model compound, bis(2,4,6-trichlorophenolato)diimidazolecopper(II) monohydrate, indicates that the resonance Raman bands are due to enhancement of phenolic vibrational modes. For the model (Cu(II) compound, a normal coordinate analysis was used to aid our assignment of the observed resonance bands at 1562, 1463, 1311, and 1122 cm-1 to A1 vibrational modes of the 2,4,6-trichlorophenolato moiety. These assignments are consistent with those made for Cu(II)-transferrins. The latter assignments were based upon calculated A1 frequencies for p-methylphenol (Cummings, D.L., and Wood, J.L. (1974), J. Mol. Struct. 20, 1). The wavelength shifts in the resonance bands for the model compound from those for Cu(II)-transferrins are due to the influence of the chloro substituents on the planar vibrations of phenol. These results clearly identify tyrosine as a ligand in copper binding to transferrins.     

Antimicrobial effects of the macrocyclic Cu(II)-tetraanhydroaminobenzaldehyde complex

We report a case of a child with Noonan phenotype and incidental radiographic findings of mediastinal neuroblastoma. Recent studies have reported an increased association of Noonan syndrome with some malignancies, and the case we present here is the first reported case to our knowledge of an association of neuroblastoma with Noonan syndrome.