Chelated complexes of cadmium(II), cobalt(II), copper(II), mercury(II), nickel(II), uranyl(II) and zinc(II) with benzil bis(4-phenylthiosemicarbazone)

Summary Complexes of Co^II, Ni^II, Cu^II, Zn^II, Cd^II, Hg^II and UO ₂ ^II with benzil bis(4-phenylthiosemicarbazone), H₂BPT, have been synthesized and their structures assigned based on elemental analysis, molar conductivity, magnetic susceptibility and spectroscopic measurements. The i.r. spectra suggest that the ligand behaves as a binegative quadridentate (NSSN) (Co^II, Cu^II, Hg^II and UO ₂ ^II complexes) or as a binegative quadridentate-neutral bidentate chelating agent (Ni^II, Zn^II and Cd^II complexes). Octahedral structures for the Co^II and Ni^II complexes and square-planar structure for the Cu^II complex are suggested on the basis of magnetic and spectral evidence. The crystal field parameters (Dq, B and _B) for the Co^II complex are calculated and agree fairly well with the values reported for known octahedral complexes. The ligand can be used for the microdetermination of Ni^II ions of concentration in the 0.4–6×10^–4 mol l^–1 range and the apparent formation constant for the species generated in solution has also been calculated.     

Formation of Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I) and Cd(II) hexacyanocobaltates

A study is reported of the formation of Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I) and Cd(II) hexacyanocobaltates. The results show that the precipitates form by reaction of the metal ions with KCo(CN)(6)(2-) ion-pairs in 1:1 ratio, followed by solid phase transformations.     

N-benzamidosalicylaldimine complexes of copper(II), nickel(II), cobalt(II), iron(II), manganese(II), oxyvanadium(IV) and oxytitanium(IV)

Summary N-benzamidosalicylaldimine (H₂L) complexes of Cu^II, Ni^II, Co^II, Fe^II, Mn^II. VO_IV and TiO_IV have been prepared. The ligand probably coordinates to the metal from the hydroxyl, carbonyl and imino groups.     

Complexes of dicamba with cadmium(II), copper(II), mercury(II), lead(II) and zinc(II)

New solid complexes of a herbicide known as dicamba (3,6-dichloro-2-methoxybenzoic acid) with Pb(II), Cd(II), Cu(II) and Hg(II) of the general formula M(dicamba)₂·xH₂O (M=metal, x=0-2) and Zn₂(OH)(dicamba)₃·2H₂O have been prepared and studied. The complexes have different crystal structures. The carboxylate groups in the lead, cadmium and copper complexes are bidentate, chelating, symmetrical, in Hg(dicamba)₂·2H₂O - unidentate, and in the zinc salt - bidentate, bridging, symmetrical. The anhydrous compounds decompose in three stages, except for the lead salt whose decomposition proceeds in four stages. The main gaseous decomposition products are CO₂, CH₃OH, HCl and H₂O. Trace amounts of compounds containing an aromatic ring were also detected. The final solid decomposition products are oxychlorides of metals and CuO. This revised version was published online in July 2006 with corrections to the Cover Date.     

New Complexes of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) with 3,3-dimethylglutaric Acid

Conditions for the preparation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)3,3-dimethylglutarates were investigated and their quantitative composition, solubility in water at 293 K and magnetic moments were determined. IR spectra and powder diffraction patterns of the complexes prepared with general formula MC₇H₁₀O₄⋅nH₂O (n=0−2) were recorded and their thermal decomposition in air were studied. During heating the hydrated complexes of Mn(II),Co(II), Ni(II) and Cu(II) are dehydrated in one step and next all the anhydrous complexes decompose to oxides directly (Mn, Co, Zn) or with intermediate formation free metal (Ni,Cu) or oxocarbonates (Cd). The carboxylate groups in the complexes studied are bidentate. The magnetic moments for the paramagnetic complexes of Mn(II), Co(II), Ni(II) and Cu(II)attain values 5.62, 5.25, 2.91 and 1.41 M.B., respectively. This revised version was published online in August 2006 with corrections to the Cover Date.     

Determination of Lead(II), Copper(II), Zinc(II), Cobalt(II), Cadmium(II), Iron(III), Mercury(II) using sequential injection extractions

Sequential injection analysis is still dominated by single component analysis. In this proposed robust, economical simple instrumental system seven different metal ions are determined simultaneously using thin-film sequential injection extraction (SIE) with multivariate calibration and multiwavelength detection. Dithizone, in ethanol, is used as extractant and the metal dithizonates’ spectra are generated by a diode array spectrophotometer between 300 and 700 nm. The SI thin-film extraction using water miscible with ethanol works due to the hydrophobic interaction of ethanol with the Teflon wall to create a thin film. A sample frequency of 27 samples per hour was obtained with a sample carry-over of less than 1%. The results of the proposed sequential injection extraction system compare favourably with the results obtained by using standard atomic absorption spectrometry (AAS) methods on conventional extraction samples.     

Complexation of managanese(II), cobalt(II), nickel(II), zink(II), and cadmium(II) cations with amoxicillin

The interaction of amoxicillin anions (Axn^?) with Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺, and Cd²⁺ in aqueous solution at 20°C and an ionic strength of 0.1 (KNO₃) has been studied pH-metrically. In a neutral and weak alkaline solution, MAxn⁺ and M(OH)Axn complexes are formed. The formation constants and the pH ranges of existence of these complexes have been determined.     

Organic acid solutions in the chromatography of inorganic ions. VII. Cation exchange of Mg(II), Ca(II), Sr(II), Ba(II), Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II) and Fe(III) in succinate media

Summary The cation-exchange behaviour of Mg(II), Ca(II), Sr(II), Ba(II), Mn(II), Cd(II), Co(II), Ni(II), Zn(II), Cu(II) and Fe(III) in succinate media at various concentrations and pH, was studied with Dowex 50 WX8 resin (200–400 mesh) in the NH ₄ ⁺ form. As examples separations of Cd(II)/Co(II), Cd (II)/Ni(II), Fe(III)/Cu(II)/Ni(II) and Mg(II)/Ca(II)/Sr(II)/Ba(II) have been achieved.This work was supported by C.N.R. of Italy.     

Preparation and characterization of vanillin thiosemicarbazone complexes with Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)

Complexes of vanillin thiosemicarbazone (3-methoxy-4-hydroxybenzaldehyde thiosemicarbazone), (vtsch) with several divalent metal ions have been isolated. Structures have been assigned to these complexes based on electrical conductivity, magnetic susceptibility and spectroscopic measurements     

Zinc(II), cadmium(II), mercury(II), and ethylmercury(II) complexes of phosphinothiol ligands

Neutral zinc, cadmium, mercury(II), and ethylmercury(II) complexes of a series of phosphinothiol ligands, PhnP(C6H3(SH-2)(R-3))3-n (n = 1, 2; R = H, SiMe3) have been synthesized and characterized by IR and NMR ((1)H, (13)C, and (31)P) spectroscopy, FAB mass spectrometry, and X-ray structural analysis. The compounds [Zn{PhP(C6H4S-2)2}] (1) and [Cd{Ph2PC6H4S-2}2] (2) have been synthesized by electrochemical oxidation of anodic metal (zinc or cadmium) in an acetonitrile solution of the appropriate ligand. The presence of pyridine in the electrolytic cell affords the mixed complexes [Zn{PhP(C6H4S-2)2}(py)] (3) and [Cd{PhP(C6H4S-2)2}(py)] (4). [Hg{Ph2PC6H4S-2}2] (5) and [Hg{Ph2PC6H3(S-2)(SiMe3-3)}2] (6) were obtained by the addition of the appropriate ligand to a solution of mercury(II) acetate in methanol in the presence of triethylamine. [EtHg{Ph2PC6H4S-2}] (7), [EtHg{Ph2P(O)C6H3(S-2)(SiMe3-3)}] (8), [{EtHg}2{PhP(C6H4S-2)2}] (9), and [{EtHg}2{PhP(C6H3(S-2)(SiMe3-3))2}] (10) were obtained by reaction of ethylmercury(II) chloride with the corresponding ligand in methanol. In addition, in the reactions of EtHgCl with Ph2PC6H4SH-2 and with the potentially tridentate ligand PhP(C6H3(SH-2)(SiMe3-3)) 2, cleavage of the Hg-C bond was observed with the formation of [Hg{Ph2PC6H4S-2}2] (5) and [Hg(EtHg) 2{PhP(O)(C6H3(S-2)(SiMe3-3))2}2] (11), respectively, and the corresponding hydrocarbon. The crystal structures of [Zn3{PhP(C6H4S-2)2}2{PhP(O)(C6H4S-2)2}] (1*), [Cd2{Ph2PC6H4S-2}3{Ph2P(O)C6H4S-2}] (2*), 3, 5, 6, [EtHg{Ph2P(O)C6H4S-2}] (7*), 8, 9, [{EtHg}2{PhP(O)(C6H3(S-2)(SiMe3-3))2}] (10*), and 11 are discussed. The molecular structures of 1, 2, 4, 7, and 10 have also been studied by means of density functional theory (DFT) calculations.     

Thermal decompositions of formates. Part IV. Thermal dehydrations of Mg(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) formate dihydrates

The thermal dehydrations of formate dihydrates of Mg(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) were studied by means of thermogravimetry, differential thermal analysis and differential scanning calorimetry in air.The reaction orders of dehydration obtained by the dynamic and the static methods were found to be 2/3 for all the salts examined, which indicated that the rate of dehydration was controlled by a chemical process at a phase boundary. This was confirmed by microscopic observation.The values of activation energy, frequency factor and the enthalpy change of dehydration for all salts examined, were 21–30 kcal mole^?1, 10¹⁰-10¹² sec^?1 and 28–31 kcal mole^?1, respectively.The temperature at which the dehydration occurred was regarded as a measure of the strength of the metalOH₂ bond, and this temperature increased with increasing the reciprocal of the radius of the metallic ion.     

Adsorption of Pb(II), Cu(II), Cd(II), Zn(II), Ni(II), Fe(II), and As(V) on bacterially produced metal sulfides

The adsorption of Pb(II), Cu(II), Cd(II), Zn(II), Ni(II), Fe(II) and As(V) onto bacterially produced metal sulfide (BPMS) material was investigated using a batch equilibrium method. It was found that the sulfide material had adsorptive properties comparable with those of other adsorbents with respect to the specific uptake of a range of metals and, the levels to which dissolved metal concentrations in solution can be reduced. The percentage of adsorption increased with increasing pH and adsorbent dose, but decreased with increasing initial dissolved metal concentration. The pH of the solution was the most important parameter controlling adsorption of Cd(II), Cu(II), Fe(II), Ni(II), Pb(II), Zn(II), and As(V) by BPMS. The adsorption data were successfully modeled using the Langmuir adsorption isotherm. Desorption experiments showed that the reversibility of adsorption was low, suggesting high-affinity adsorption governed by chemisorption. The mechanism of adsorption for the divalent metals was thought to be the formation of strong, inner-sphere complexes involving surface hydroxyl groups. However, the mechanism for the adsorption of As(V) by BPMS appears to be distinct from that of surface hydroxyl exchange. These results have important implications to the management of metal sulfide sludge produced by bacterial sulfate reduction.     

Spectral,thermal and magnetic investigations of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) 4-methylphthalates

Conditions for the preparation of Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II) 4-methylphthalates were investigated and their composition, solubility in water at 295 K and magnetic moments were determined. IR spectra and powder diffraction patterns of the complexes prepared with molar ratio of metal to organic ligand of 1.0:1.0 and general formula: M [ CH₃C₆H₃(CO₂)₂]·nH₂o (n=1-3) were recorded and their decomposition in air were studied. During heating the hydrated complexes are dehydrated in one (Mn, Co, Ni, Zn, Cd) or two steps (Cu) and next the anhydrous complexes decompose to oxides directly (Cu, Zn), with intermediate formation of carbonates (Mn, Cd), oxocarbonates (Ni) or carbonate and free metal (Co). The carboxylate groups in the complexes studied are mono- and bidentate (Co, Ni), bidentate chelating and bridging (Zn) or bidentate chelating (Mn, Cu, Cd). The magnetic moments for paramagnetic complexes of Mn(II), Co(II), Ni(II) and Cu(II) attain values 5.92, 5.05, 3.36 and 1.96 M.B., respectively. This revised version was published online in July 2006 with corrections to the Cover Date.     

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.     

Reaction of cefalexine with manganese(II), cobalt(II), nickel(II), zinc(II), and cadmium(II) ions

The reaction of cefalexine anions (Cpx^?) with Mn²⁺, Co²⁺, Ni²⁺, Zn²⁺, and Cd²⁺ ions in aqueous solution at 20°C and ionic strength 0.1 was studied by pH-metry. In weakly alkaline medium, unstable complexes MCpx⁺ and M(OH)Cpx are formed, in which Cpx^? behaves as a monodentate lidand coordinated through the amino group.     

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).     

Thermal behaviour of Co(II), Ni(II), Cu(II), Zn(II), Hg(II) and Pd(II) complexes with isatin-β-thiosemicarbazone

The isatin-β-thiosemicarbazone (ITC) complexes of Co(II), Ni(II), Cu(II), Zn(II), Hg(II) and Pd(II) were prepared and characterized by elemental analysis, as well as molar conductivity, magnetic susceptibility, FTIR, UV-Vis and ¹H NMR spectroscopic methods. The complexes were also studied for its thermal stability. They all behaviour as anhydrous complexes and its thermolysis passes through the stages of deamination (517–547 K) and complete thermal decomposition (619–735 K).     

Cobalt(II), nickel(II), copper(II), zinc(II) and uranyl(VI) complexes of acetylacetone bis(4-phenylthiosemicarbazone)

Summary Reaction of one mole of acetylacetone with two moles of 4-phenylthiosemicarbazide yields the unusual Schiff base, MeC(=N-NHCSNHPh)CH₂C(=NNHCSNHPh)Me. APT = H₂L) acetylacetone bis(4-phenylthiosemicarbazone). The complexes of Co^II, Ni^II, Cu^II, Zn^II and U^VIO₂ have been prepared and characterized by analytical, i.r., electronic spectral and magnetic measurements. The Co^II, Ni^II and Cu^II complexes have been assigned square-planar stereochemistry on the basis of magnetic and spectroscopic studies. The ligand is a neutral or dibasic quadridentate SNNS donor as revealed by i.r. spectral studies.     

Chelation behaviour of nitroso- pyrazolones with Mn(II), Co(II), Ni(II), Cu(II) AND Zn(II)

Infrared (IR), nuclear magnetic resonance (NMR), thermogravimetric analysis (TG), derivative thermogravimetric analysis (DTG), differential thermal analysis (DTA) and molar conductivity studies have been carried out on the chelates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) with 3-methyl- and 3-phenyl-4-nitroso-5-pyrazolones. The solid chelates were synthesized, separated, analyzed and their structures were elucidated. The data obtained show that almost all of the prepared chelates contain water molecules in their coordination sphere. The initial stage in the thermal decomposition process of these chelates shows the presence of water molecule, the second denotes to the intermediate products. The final decomposition products were found to be the respective metal oxides. The NMR spectrum of 3-methyl-4-nitroso-5-pyrazolone ligand shows the existence of the oxime rather than the nitroso form. 3-phenyl-4-nitroso-5-pyrazolone acts as a neutral bidentate ligand whereas 3-methyl-4-nitroso-5-pyrazolone acts as monobasic bidentate ligand bonded to the metal ions through the two oxygen atoms of the carbonyl and nitroso groups. The solid chelates prepared behave as non-electrolytes in DMF solution. The coordination numbers of the obtained chelates using 3-methyl-4-nitroso-5-pyrazolone are four on applying the mole ratio 1:1 and six on using 1:2 mole ratio. In case of using the ligand 3-phenyl-4-nitroso-5-pyrazolone the coordination number is six in both cases. This revised version was published online in August 2006 with corrections to the Cover Date.     

Complexes of Co(II), Ni(II), Cu(II), and Pd(II) with Sulfametrole-Cyclodiphosph(V)azane Derivatives

Novel [1,3-di-[N ₁ -4-methoxy-1,2,5-thiadiazole-3-yl-sulfanilamide(sulfametrole)]-2″4-bis-[1,3-dithiole-2-thione-4,5-dithiolate]-2′,4′-dichl-orocyclodiphosph(V)azane] (III) , was prepared and their coordinating behavior towards the metal ions Co(II), Ni(II), Cu(II), and Pd(II) was studied. The structures of the isolated products are proposed based on elemental analyses, IR, UV, ¹ H, and ³¹ P NMR, ESR, magnetic susceptibility, molar ratio, conductometric titration and electrical conductivity measurements. The prepared complexes showed high to moderate bactericidal activity compared with the ligand.