Synergistic solvent extraction studies of uranium(VI) using a combination of naphthenic acid and various neutral donors into benzene

The equilibrium extraction behavior of uranium(VI) using a benzene solution containing naphthenic acid either alone or combined with one of the adductants viz., diphenyl sulphoxide, dinonyl sulphoxide, tri-n-butyl phosphate, triphenyl phosphine oxide, tri-n-octyl phosphine oxide, triphenyl arsine oxide, 2,9 dimethyl 1,10-phenanthroline, 1,10-phenanthroline, 4,7-diphenyl 1,10-phenanthroline, 2,2′-bipyridyl and 2,2′-biquinoline is described. The enhancement in the extraction by addition of such neutral adducts is explained in terms of adduct formation of the metal chelates in the organic phase. The composition of the extracted species is obtained from slope analysis and pH_0,5 values are also obtained. The effect of various parameters such as equilibrium pH, extractant concentration, various diluents on the extraction of U(VI) with 2% naphthenic acid has been carried out. Stripping or back extraction with various mineral acids was also studied.     

Divalent osmium complexes: synthesis,characterization, strong red phosphorescence,and electrophosphorescence

We report new divalent osmium complexes that feature strong red metal-to-ligand-charge-transfer (MLCT) phosphorescence and electrophosphorescence. The general formula of the complexes is Os(II)(N-N)(2)L-L, where N-N is either a bipyridine or a phenanthroline and L-L is either a phosphine or an arsine. New polypyridyl ligands synthesized are 4,4'-di(biphenyl)-2,2'-bipyridine (15) and 4,4'-di(diphenyl ether)-2,2'-bipyridine (16), and the 1,10-phenanthroline derivatives synthesized are 4,7-bis(p-methoxyphenyl)-1,10-phenanthroline (17), 4,7-bis(p-bromophenyl)-1,10-phenanthroline (18), 4,7-bis(4'-phenoxybiphen-4-yl)-1,10-phenanthroline (19), and 4,7-bis(4-naphth-2-ylphenyl)-1,10-phenanthroline (20). 4,4'-Diphenyl-2,2'-bipyridine (21) and 4,7-diphenyl-1,10-phenanthroline (22) were also used in these studies. Strong pi-acid ligands used were 1,2-bis(diphenylarseno)ethane (23), cis-1,2-bis(diphenylphosphino)ethylene (24), and cis-1,2-vinylenebis(diphenylarsine) (25). Ligand 25 is used for the first time in these types of luminescent osmium complexes. These compounds feature strong MLCT absorption bands in the visible region and strong red phosphorescent emission ranging from 611 to 651 nm, with quantum efficiency up to 45% in ethanol solution at room temperature. Red organic light-emitting diodes (OLEDs) were successfully fabricated by doping the Os(II) complexes into blend of poly(N-vinylcarbazole) (PVK) and 2-tert-butylphenyl-5-biphenyl-1,3,4-oxadiazole (PBD). Brightness over 1400 cd/m(2) for a double-layer device has been reached, with a turn-on voltage of 8 V. The maximum external quantum efficiency was 0.64%. Commission Internationale de l'Eclairage (CIE) chromaticity coordinates (x, y) of the red electrophosphorescence from the complexes are (0.65, 0.34), which indicates pure red emission.     

Redox-driven transport of copper ions in an emulsion liquid membrane system

A new redox-driven type of emulsion liquid membrane separation is described. Milligram amounts of copper(II) in 0.2 M hydrochloric acid were reduced to copper(I) in the presence of ascorbic acid (1 M≡1 mol l⁻¹). The copper solution was emulsified with a (1+4) mixture of toluene and n-heptane using Span-80 (sorbitan monooleate) as an emusifier. The resulting water-in-oil emulsion was dispersed in 0.2 M hydrochloric acid containing hydrogen peroxide and neocuproine (2,9-dimethyl-1,10-phenanthroline) by stirring for 10 min. The copper in the internal aqueous phase was selectively transported to the external one, leaving other heavy metals (e.g., Mn, Co, Ni, Cd and Pb) in the internal aqueous phase. After collecting the dispersed emulsion globules, they were demulsified by heating and the metals in the segregated aqueous phase were determined by graphite-furnace atomic absorption spectrometry (GFAAS). The selective transport of copper offered the multielement separation of trace heavy metals from a copper matrix, allowing the GFAAS determination of impurities at the 0.01% level in copper metal.     

Separation and inductively coupled plasma optical emission spectrometric (ICP-OES) determination of trace impurities in nuclear grade uranium oxide

A simple and rapid inductively coupled plasma optical emission spectrometric method for the determination of trace level impurities like REEs, Y, Cd, Co, V, Mg, B, Ca, Cr, Mn, Ni, Cu, Zn and Al in uranium oxide samples is described. The method involves solvent extraction separation of uranium from 6 M HNO₃ acid medium using di (2-ethyl hexyl) phosphoric acid in toluene, which selectively separates uranium leaving behind the trace impurities in the aqueous media, for quantification by ICP-OES. The method has been applied to few synthetic samples and five certified reference U₃O₈ standards. The results are compared with other methods such as TBP-TOPO-CCl₄ and 1,2 diaminocyclohexane N,N,N′,N′-tetra acetic acid (CyDTA)–ammonium hydroxide (NH₄OH) separation techniques. Different experimental parameters like contact time, acidity, aqueous to organic ratio etc., are optimized for better and accurate results. The method is simple, rapid, accurate and precise for all the studied elements, showing a relative standard deviation of 1.5–12.0% at trace levels studied (5.5–12% at 0.2 μg/mL and 1.5–6.0% at 0.5 μg/mL), on the synthetic samples prepared from high purity oxides.     

Photometric determination of selenium with ferrocene

A sensitive spectrophotometric method for the determination of selenium has been developed. The method depends on a redox reaction between selenious acid in 8M hydrochloric acid and a chloroform solution of ferrocene. One mole of selenious acid produces 4 moles of ferricenium ions, which are then oxidized by bromine water. The resulting iron(III) is reduced to iron(II) and determined with 1,10-phenanthroline. The relative standard deviation for 20 mug of selenium was 1.1%. The apparent molar absorptivity of the final solution, referred to selenious acid, is 4.23 x 10(4) 1. mole(-1). cm(-1) at 512 nm. This method has been used to determine selenium in copper metal.     

Synthesis of 2-aminomethyl-1,10-phenanthroline. A new chelating agent and versatile synthon for other chelating compounds

The synthesis of 2-aminomethyl-1,10-phenanthroline ( 4 ) from 1,10-phenanthroline ( 1 ) is described. The reduction of 2-cyano-1,10-phenanthroline ( 3 ) to 4 in the presence of 10% palladium on carbon in acetic acid under mild reaction conditions also proved to be a very efficient method for conversion of cyanopyridines to methylaminopyridines.     

Uranium determination in water samples by liquid scintillation counting after cloud point extraction

The aim of this study is the radiometric determination of uranium in waters by liquid scintillation counting (LSC) after pre-concentration of the element by cloud point extraction (CPE). For CPE, tributyl phosphate (TBP) is used as the complexing agent and (1,1,3,3-Tetramethylbutyl)phenyl-polyethylene glycol (Triton X-114) as the surfactant. The measurement is performed after phase separation by mixing of the surfactant phase with the liquid scintillation cocktail. The effect of experimental conditions such as pH, reactant ratio (e.g. m(TBP)/m(Triton), ionic strength (e.g. [NaCl]) and the presence of other chemical species (e.g. Ca²⁺ and Fe³⁺ ions as well as humic acid and silica colloids) on CPE has been investigated. According to the experimental results the total method efficiency is (13 ± 2)% and the chemical recovery (50 ± 10)% at pH 4 and reactant ratio (V(TBP)/V(Triton) = 0.1). Regarding the other parameters, generally Ca²⁺ and Fe³⁺ ions as well as the presence of colloidal species in solution (even at low concentrations) results in significant decrease of the chemical recovery of uranium. On the other hand increasing NaCl concentration leads to enhancement of chemical recovery. The detection limit under optimum experimental conditions has been found to be 0.5 Bq L^?1 indicating that the method could be applied only to waters samples with increased uranium concentration. Moreover, the negative effect of the chemical species found in natural waters limits the applicability of the method with the respect to environmental radioactivity measurements.     

Synthesis of chelating tertiary phosphine oxides via palladium-catalysed C–P bond formation

Bis(diphenylphosphine oxides) and bis(tert-butyl(phenyl)phosphine oxides) of 1,10-phenanthroline, 2,2′-bipyridine and pyridine were synthesised in good yields via the Pd(OAc)₂/dppf mediated cross-coupling reactions between 6,6′-dichloro-2,2′-bipyridine, 2,9-dichloro-1,10-phenanthroline, or 2,6-dichloropyridine and the corresponding secondary phosphine oxides. These compounds represent potential tetradentate chelating ligands for ions of f-block elements.     

Synthesis,Crystal Structure and Thermal Stability of Complex [Cu（C_（14）H_（10）O_4）（C_（12）H_8N_2）_2]·2H_2O

The title complex has been synthesized with 2,2'-biphenyl dicarboxylic acid and 1,10-phenanthroline(phen)in the solvent mixture of water and methanol.It crystallizes(C38H28CuN4O6,Mr = 700.1)in triclinic,space group P1 with a = 1.0868(2),b = 1.2175(2),c = 1.6206(3)nm,α = 110.161(2),β = 102.605(3),γ = 93.667(2)o,V = 1941.6(6)nm3,Dc = 1.198 g/cm3,Z = 2,F(000)= 722,R = 0.0558 and wR = 0.1208.The crystal structure shows that the copper atom is coordinated with one oxygen atom from 2,2'-bphenyl dicarboxylic acid molecule and four nitrogen atoms from two 1,10-phenanthroline molecules,forming a distorted square-pyramidal coordination.The TG analysis shows that the title complex is stable under 160.0 ℃.     

Hydrothermal Synthesis, Crystal Structure and Thermal Stability of [Ni(phen)3]·(C8H12O4)·(H2O)14

One novel complex [Ni(phen)3]·(C8H12O4)·(H2O)14 with hexane dicarboxylic acid and 1,10-phenanthroline has been hydrothermally synthesized and characterized. Crystal data: monoclinic, space group C2/c, a = 2.3475(5), b = 1.2208(2), c = 1.9499(4) nm, β = 114.682(3)o, V = 5.0778(16) nm3, Dc = 1.339 g/cm3, Z = 4, μ(MoKα) = 0.458 mm-1, F(000) = 2168, GOOF = 1.014, R = 0.0401 and wR = 0.0961. The nickel(Ⅱ) center in the title complex is coordinated with six nitrogen atoms of three 1,10-phenanthroline molecules, giving a distorted octahedral coordination geometry. However, the nickel(Ⅱ) ion does not coordinate to the hexane dicarboxylic acid. The complex molecules form a 3D structure through hydrogen bonds. TG analysis shows that the title complex is stable below 240.0 ℃.     

Hydrothermal Synthesis, Crystal Structure and Electrochemical Properties of Complex Cu(α-Furacrylic acid)2(phen)

The title complex (C26H18CuN2O6, Mr=517.96) has been synthesized by the reaction of α-furanacrylic acid with 1,10-phenanthroline (phen) in the solvent mixture of water and methanol. Crystal data: monoclinic, space group C2/c with a=2.2927(4), b=1.01248(18), c=1.05061(18) nm, β=111.188(3)°, V=2.274(7) nm3, Dc=1.513 g/cm3, Z=4, F(000)=1060,μ=1.007mm-1, R=0.0320 and wR=0.0781. The crystal structural analysis shows that the copper atom is coordinated with four oxygen atoms from two α-furacrylic acids and two nitrogen atoms from 1,10-phenanthroline, giving a distorted octahedral coordination geometry. The result of electrochemical analysis shows that the electron transfer in the electrode reaction is quasi-reversible.     

Hydrothermal Synthesis,Crystal Structure and Thermal Stability of [Ni（phen）3]-（C8H12O4）-（H2O）14

One novel complex [Ni（phen）3],（C8H12O4）·（H2O）14 with hexane dicarboxylic acid and 1,10-phenanthroline has been hydrothermally synthesized and characterized. Crystal data： monoclinic, space group C2/c, a = 2.3475（5）, b = 1.2208（2）, c = 1.9499（4） nm, β= 114.682（3）°, V = 5.0778（16） nm^3, Dc = 1.339 g/cm^3, Z = 4,μ（MoKa） = 0.458 mm^-1, F（000） = 2168, GOOF = 1.014, R = 0.0401 and wR = 0.0961. The nickel（H） center in the title complex is coordinated with six nitrogen atoms of three 1,10-phenanthroline molecules, giving a distorted octahedral coordination geometry. However, the nickel（Ⅱ） ion does not coordinate to the hexane dicarboxylic acid. The complex molecules form a 3D structure through hydrogen bonds. TG analysis shows that the title complex is stable below 240.0 ℃.     

Flame AAS determination of dopants and trace metal impurities in single crystals of potassium titanylphosphate

A flame AAS method is used for the determination of dopants and impurities in potassium titanylphosphate (KTP) single crystals. Sample digestion using sulphuric acid and hydrofluoric acid is proposed as being the most appropriate procedure. The effect of major and minor components in the sample solution on the analytical signal is studied. The content of the dopants Cr, Mn and Ni (at a level of about 1 mg g(-1)) as well as the content of the impurities Fe, Na, Mg, W and Al (from 4 mug g(-1), depending on the trace metal) in the KTP single crystals is determined. The precision of the method is characterized by a relative standard deviation of 3-10%. The accuracy is checked by comparison with ICP-AES data for the trace element content in the KTP single crystals.     

Hydrothermal Synthesis,Crystal Structure and Electrochemical Properties of Complex [Cd(phen)_3]·(ClO_4)_2·(p-MBA)_2·(H_2O)_2

One new cadmium complex [Cd(phen)3]·(ClO4)2·(p-MBA)2·(H2O)2 has been hydro-thermally synthesized by reacting p-methylbenzoic acid (p-MBA),1,10-phenanthroline (phen) and cadmium perchlorate. It crystallizes in the triclinic system,space group P1,with a=1.2809(3),b= 1.3431(3),c=1.3734(3) nm,α=84.259(4),β=71.603(3),γ=74.424(3)o,V=2.1594(8) nm3,Dc= 1.532 g/cm3,Z=2,F(000)=1008,μ=0.697 mm-1,R=0.0646 and wR=0.1648. The crystal structure shows that the cadmium ion is coordinated with six nitrogen atoms from three 1,10-phenanthroline molecules,forming a distorted octahedral coordination geometry. The result of electrochemical property analysis shows that the electron transfer in the electrode reaction is irreversible.     

Synthesis, Crystal Structure and Thermoanalysis of Complex of Zn(Ⅱ) with Aminomethanesulfonic Acid-5-bromosalicylaldelyde Schiff Base

The title complex [Zn(L)(phen)(CH3OH)] (L= C8H6BrO4NS, aminomethanesulfonic acid 5-bromo-salicylaldelyde schiff base; phen = 1,10-phenanthroline) has been synthesized and characterized by X-ray diffraction method. The crystal belongs to monoclinic, space group P21/c with a = 1.8712(3), b = 1.38008(19), c = 0.83685(12) nm, β = 97.791 (2)°, Mr = 569.72, V = 2.1411(5)nm3,Z= 4, Dc = 1.767 g/cm3, μ = 3.151 mm-1, F(000) = 1144, the final R = 0.0402 and wR = 0.0885. The central Zn(Ⅱ) is six-coordinated by one nitrogen and two oxygen atoms from the Schiff base, two nitrogen atoms from 1,10-phenanthroline and one oxygen from methanol to form a distorted octahedral coordination geometry.     

Synthesis,Crystal Structure and Thermoanalysis of Complex of Zn(II) with Aminomethanesulfonic Acid-5-bromosalicylaldelyde Schiff Base

1 INTRODUCTION There is considerable interest in the study of Schi- ff-base complexes containing sulfur and complexes of amino acid Schiff-bases[1~8] due to their antiviral, anticancer and antibacterial activities. Furthermore, zinc, as one of the most important trace elements, plays a versatile role in biological systems due to its structural and catalytic roles in enzymes[9, 10]. There- fore, many efforts have been expended on the study of synthetic analogues of zinc enzymes in the hope…     

Indirect spectrophotometric determination of sulphide with the ternary complex system Ag(I)-phen-BPR

Trace amounts of sulphide can be determined from its effect on the ternary complex system of Ag(+), Bromopyrogallol Red (BPR), and 1,10-phenanthroline (phen). Sulphide in the range 5-120 ng/ml causes a decrease in absorption, that is a linear function of the concentration. Common metal ions such as Na(+), K(+), Ca(2+), Mg(2+), Al(3+), Mn(2+) and anions such as F(-), Cl(-), NO(-)(3), SO(2-)(4), CO(2-)(3), and PO(3-)(4) at the 4 mug/ml level or more do not interfere, but I(-) or CN(-) must be absent.     

Preparation,Crystal Structure and Thermal Decomposition Process of Dysprosium Benzoate Complex with 1,10.Phenanthroline

A dinuclear dysprosium（III） complex with benzoic acid and 1,10-phenanthroline, [Dy（BA）3phen]2 （BA = benzoate, PHEN = 1,10-phenanthroline） （C66H46Dy2NaO12, Mr = 1412.07） was synthesized and characterized by elemental analysis, UV, IR, X-ray diffraction, molar conductance and TG-DTG techniques. It crystallizes in triclinic, space group P1 with a = 10.773（2）, b = 11.933（3）, c = 12.417（5） A, α= 105.226（3）,β= 93.470（3）, γ= 113.475（2）°, V= 1388.0（7）, Z = 1, Dc = 1.689 g/cm3, μ（MoKa） = 2.742 mm-1 and F（000） = 698. R = 0.0210, wR = 0.0538. In the crystal, each Dy（III） ion is eight-coordinated by one bidentate chelating carboxylate group, four bidentate bridging carboxylate groups and one 1,10-phenanthroline molecule. The thermal decomposition process of [Dy（BA）3phen]2 has been determined by thermal analysis.     

Synthesis, structure and luminescent properties of yttrium benzene dicarboxylates with one- and three-dimensional structure

The synthesis and structure of two yttrium benzene dicarboxylates, 1 is proportional to [[Y2(C12N2H8)2(C8H4O4)3].H2O], I and 3 is proportional to [[Y2(C12N2H8)2(C8H4O4)3]], II with one- and three-dimensional structure has been accomplished employing hydrothermal methods in the presence of 1,10-phenanthroline. While I is formed with phthalic aid (1,2-BDC), II is formed using isophthalic acid (1,3-BDC). Both the structures appear to have comparable building units, an eight-membered ring and a paddle-wheel arrangement, connected through the carboxylic acid. The 1,10-phenanthroline, connected to Y as a secondary ligand, occupies the inter-chain spaces in I, and projects into the channels in II. The channels in II are inter-connected. Photoluminescence studies indicate that both I and II exhibit a bathochromic shift with respect to the acids (1,2-BDC and 1,3-BDC) and a hypsochromic shift with respect to 1,10-phenanthroline. Both the compounds exhibit reasonable pi...pi interactions.     

Hydrothermal Synthesis,Crystal Structure and Electrochemical Properties of the Copper(II) Complex [Cu_4O_4(phen)_4(ClC_6H_4COO)_2(H_2O)_2]·(H_2O)_3

1 INTRODUCTION As we all know, copper is a necessary trace element for human body. For example, a large number of bi- nuclear or multi-nuclear transition metallic complex- es exist in active centers of some metalloprotein[1]. In the 1960’s, Bertand and Bock et al[2] reported the first tetra-nuclear copper complex with Cu4O3 unit. In 1996, a cyclo-tetranucleate complex bridged by pyridine was synthesized by Zhang Hua etc[3]. In 1999, Tan Xiangshi and coworkers[4] presented a cubic tet…