Stability constants of some metal dithizonates

The overall stability constants of electroneutral dithizonates of bismuth, cadmium, cobalt(II), copper(II), iron(II), lead(II), manganese(II), mercury(II), nickel, palladium(II), silver, tin(II) and zinc were determined by means of stoichiometric dilution in aqueous solution stabilized by hydroxylamine hydrochloride, at pH 5.50-10.02. Stability constants of complexes ML of bivalent metals were determined under similar conditions but with an excess of metal.     

A new selective and high affinity polymeric complexing agent for transition metal ions

Summary The synthesis and characteristics of a new chelating glycinohydroxamate-containing polymer resin is described. The functionality of the polymer is 1.76 mmolg^–1. The hydrogen capacity, water regain and adsorption capacities for iron(III), cadmium(II), cobalt(II), copper(II), nickel(II) and zinc(II) were measured at various pH values; uptake of the metal ions increased with pH and was quantitative above pH 3 for most of the metal ions. All cations studied showed high exchange rates towards the resin. The half saturation times for iron(III), cadmium(II), copper(II) and zinc(II) were all less than 1 min. The coordination behaviour of the resin was studied with the help of e.p.r., i.r., u.v. and potentiometry. The pK _a of the resin is 10.70 and the log value of the stability constants for iron(III), copper(II), lead(II), zinc(II), cobalt(II), manganese(II), cadmium(II) and nickel(II) were measured as 21.81, 19.50, 19.20, 18.59, 18.51, 18.46, 18.37 and 18.36, respectively, at 25 ° C and I = 0.2M KCl.     

Potentiometric study of complexation between taurine and metal ions

The protolytic and complexation properties of taurine are studied by a potentiometric method. The dissociation constants of 2-aminoethanesulfonic acid functional groups and the stability constants of taurine complexes with copper(II), cobalt(II), nickel(II), zinc(II), manganese(II), cadmium(II), silver(I), magnesium(II), calcium(II), strontium(II), and barium(II) ions are calculated.     

Formation and composition of the precipitates of various metal 8-selenoquinoline complexes

The effect of acidity on the precipitation of various bivalent metal 8-selenoquinoline and 8-mercaptoquinoline complexes has been systematically studied and compared. The metal ions were Zn(2+), Cd(2+), Pb(2+), Mn2+, Ni(2+), Cu(2+) and Co(2+). Most of the metal ions, except copper(II) and cobalt(II), precipitate as a. 1:2 complex, metal :ligand. However, in hydrochloric acid solution cadmium precipitates as CdR(2).2HCl and lead as PbR(2).2HCl or PbR.Cl. Copper(II) is reduced to copper(I) and precipitates as CuR.RH at pH above 2.0 and as CuR in strongly acidic solution. Cobalt(II) does not give a precipitate of composition but appears to precipitate as a mixture of CoR(2).RH and fixed CoR(2) or as other complexes. The reasons for the formation of the various types of precipitate are considered.     

The application of 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane to the extraction of metal ions

The use of 5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane (Tet) in chloroform solutions provides quantitative extraction of lead(II), cadmium(II), copper(II) and zinc(II) at different pH values from solutions containing perchlorate and cyclohexanecarboxylic acid. Nickel(II) and cobalt(II) ions are not extracted quantitatively. Single extractions of mixtures of copper with transition metals gave the best separations for the copper/nickel system. Separations of copper from cobalt, lead, manganese and iron were less satisfactory.     

Microdetermination of Mn, Fe, Co, Ni, Cu, Zn, Ag, Cd, Hg, Pb, Bi and U in inorganic and organometallic compounds with morpholinium morpholine-N-dithiocarboxylate

The chelates of morpholinium morpholine-N-dithiocarboxylate with manganese(II), iron(II), iron(III), cobalt(II), nickel, copper(II), zinc, silver, cadmium, mercury(II), lead, bismuth and uranium(VI) have been prepared and their compositions elucidated. Simple, accurate and relatively rapid procedures for the gravimetric and titrimetric microdetermination of these metals in inorganic and organometallic compounds are presented.     

Crystal Structure of 2-pyridine-2-yl-3(pyridine-2-carboxylideneamino)quinazolin-4(3H)-one and its Ligating Diversity Towards Transition Metal(II) Ions

The synthesis of a new ligand 2-pyridine-2-yl-3(pyridine-2-carboxylideneamino)-quinazolin-4(3H)-one (PPCAQ) is described together with its manganese(II), cobalt(II), nickel(II), copper(II), zinc(II) and cadmium(II) complexes. The single crystal X-ray diffraction studies of the ligand reveal the presence of two crystallographically independent molecules in asymmetric unit cell, which exhibit N…N attractive interaction. The PPCAQ and its metal complexes were characterized by analytical, spectroscopic (i.r., n.m.r and u.v.–vis), magnetic moment, conductance and thermal studies. The i.r. spectral studies reveal the ligational diversity of the PPCAQ towards different metal ions as NNN donor in cobalt(II), copper(II), zinc(II) and cadmium(II) complexes and as ONN donor in manganese(II) and nickel(II) complexes. The antimicrobial activity of all the compounds was tested; copper(II), zinc(II) and cadmium(II) complexes show enhanced antibacterial activity compared to the free ligand.     

Thermal decomposition of some divalent metal selenates

Thermogravimetry, differential thermal analysis and differential thermogravimetry have been used to study the decomposition of hydrated selenates of manganese(II), cobalt, nickel, copper(II), zinc and cadmium. Based on the results obtained, mechanisms of decomposition have been proposed. The decomposition temperatures of non-hydrates show a gradual increase from manganese(II) selenate to zinc selenate and then a sudden drop for cadmium selenate.     

Potentiometric determination of stability constants of cyanoacetato complexes of cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II) and lead(II)

Stability constants of cyanoacetato complexes of cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II) and lead(II) were determined potentiometrically at 25.0 +/- 0.1 degrees and ionic strength 2M (sodium perchlorate). The stability constants were evaluated by a weighted least-squares method.     

Transition metal complexes derived from 2-iminocyclohexanedithiocarboxylic acid

Summary The ligating properties of 2-iminocyclohexanedithiocarboxylic acid were investigated. Complexes with halides of manganese(II), iron(II), cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II) and mercury(II) were synthesized and characterized by elemental analysis, magnetic measurements, electron and i.r.¹H n.m.r. spectral studies. The results are concordant with a bidentate coordination of the—CS₂ group to the metal ions.     

Formation constants for the complexes of levulinate and acetate with manganese(II), cobalt(II), nickel(II), copper(II), zinc(II) and hydrogen ions

Formation constants are reported for the levulinate complexes of manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) at 25 degrees in 0.1M chloride medium. In addition, results are presented for the corresponding acetate complexes for comparison. Protonation constants for the two ligands are also reported.     

Ion-selective chalcogenide electrodes for a number of cations

Ion-selective chalcogenide disc electrodes have been developed which are responsive to cations such as silver, lead, chromium(III), nickel, cobalt(II), cadmium, zinc, copper(II) and manganese(II) ions. Each was prepared by using the corresponding metal chalcogenide with silver sulphide. An electrode was assembled with both a compacted and a sintered disc. The sintered electrodes were more sensitive and stable than the compacted ones. Response to silver ion was 59.5 mV pAg , to lead, nickel, cadmium, zinc and copper(II) 29.5 mV pM and to chromium(III) 20 mV pM . Cobalt(II) and manganese(II) electrodes had a non-Nernstian response of 25 mV pM . Both selenides and tellurides can be used for potentiometric determination, but the manganese(II) electrode serves as an analytical tool only when the disc consists of manganese(II) telluride and silver sulphide.     

Metal ion capillary zone electrophoresis with direct UV detection: Separation of metal cyanide complexes

Mixtures of cyanide complexes of iron(III), copper(I), iron(II), nickel(II), chromium(III), mercury(II), palladium(II), silver(I), cadmium(II), zinc(II), cobalt(II), and cobalt(III) have been separated by capillary zone electrophoresis using a fused silica capillary and 20 mM phosphate buffers containing 1–2 mM sodium cyanide. The complexes were detected by direct UV absorpticn at 214 nm; detection limits are in the mid ppb range for all metals except cadmium and zinc. The different detectability of various metal cyanide complexes enables the application of the method to the analysis of complex matrices such as cyanide plating bath solutions.     

Synthesis and characterization of iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes of salicylidene-N-anilinoacetohydrazone (H2L1) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H2L2)

Salicylidene-N-anilinoacetohydrazone (H(2)L(1)) and 2-hydroxy-1-naphthylidene-N-anilinoacetohydrazone (H(2)L(2)) and their iron(III), manganese(II), cobalt(II), nickel(II), copper(II) and zinc(II) complexes have been synthesized and characterized by IR, electronic spectra, molar conductivities, magnetic susceptibilities and ESR. Mononuclear complexes are formed with molar ratios of 1:1, 1:2 and 1:3 (M:L). The IR studies reveal various modes of chelation. The electronic absorption spectra and magnetic susceptibility measurements show that the iron(III), nickel(II) and cobalt(II) complexes of H(2)L(1) have octahedral geometry. While the cobalt(II) complexes of H(2)L(2) were separated as tetrahedral structure. The copper(II) complexes have square planar stereochemistry. The ESR parameters of the copper(II) complexes at room temperature were calculated. The g values for copper(II) complexes proved that the Cu-O and Cu-N bonds are of high covalency.     

Chemical analysis of mixtures of some heavy metals by means of differential reaction rates of ligand substitution reactions

The simultaneous determination of some heavy metals in their mixtures is described. The method is based on the differential reaction rate of ligand substitution reactions involving ethyleneglycol bis(2-aminoethylether)N,N,N',N'-tetraacetic acid (EGTA) and 4-(2-pyridylazo)-resorcinol (PAR). Various combinations at the 10^-6M level of heavy metal ions such as manganese(II), iron(III), cobalt(II), nickel(II), copper(II), zinc(II), cadmium(II), mercury(II) and lead(II) can be determined photometrically.     

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.     

过敏性哮喘患者血清中10种必需微量元素水平的研究

３４例过敏性哮喘患者血清中铁，锌、铜，锰硒铬，钴镍，钡，钼的含量水平与对照组比较，揭示：（１）铁，铜，铬的含量升高；（２）硒，镍，钴、钒的钼的含量降低；（３）锌和锰的含量差异无显著性，Ｐ〉０．０５。     

116例冠心病患者血清中10种必需微量元素水平的研究

１１６例冠心病患者血清中１０种必需微量元素的含量与正常值比较，具有如下特点：（１）铁，锌、铬，镍含量升高；２硒钴，钒，钼含量降低；（３）铜和锰差异无显著性。     

正常妊娠与妊高征患者血清中8种必需微量元素水平的研究

７８例正常妊娠妇女和４０例妊高征患者血清中铁、锌、铜、锰、硒、铬、钴和镍的含量与健康未孕妇女比较，正常妊娠妇女和妊高征患者均是铜和锰的含量升高，铁、锌、硒、铬、钴和镍含量降低；妊高征患者与正常妊娠妇女比较，则是铁、铜和锰的含量升高，锌、硒、铬、钴和镍的含量降低。     

猪胰脏中铁钙镁铜铅锌镉锰钴镍的测定

采用硝酸－过氧化氢在自动回流消化仪中消化猪胰脏,火焰原子吸收光度法测定铁、钙、镁、铜、锌、铅、镉、锰、钴、镍的含量。,方法简便,快速,结果令人满意,并对猪胰脏食用价值进行了评价。