Column Chromatography and Kinetics of Nucleosides and Nucleic Acid Bases on Immobilized Nickel- and Cobalt-CDAE-Sporopollenin

ABSTRACT

Sporopollenin, a natural polymer, has been modified for application as a ligand-exchange material. The ligand-exchange Chromatography with the functionalized Lycopodium clavatum is a useful method for the rapid separation of nucleosides and nucleic acid bases. The synthesis of tris(carboxymethyl) ethylene diamine Lycopodium clavatum has been described. The resin contained functional diaminoethane and carboxyl groups. Nickel(II) and cobalt(II) metal ions can easily be immobilized on this carboxylated-diamino-ethyl (CDAE)-sporopollenin. Physico-chemical and chelating properties of Lycopodium clavatum have been studied extensively. Ligand-exchange chromatography of CDAE-sporopollenin has also been compared to the conventional synthetic chelex-100 resin. The kinetics of cytidine in CDAE-sporopollenin resin has been investigated. The rate measurements have been made by a potentiometric technique. The relative rates at which nucleosides bind to the resin are determined by the actual chemical-exchange reaction between ligands and resin.     

Sorption of Heavy Metal Ions on New Metal-Ligand Complexes Chemically Derived from Lycopodium clavatum

Abstract

Sorption of heavy metal ions from aqueous solution has been investigated as a function of pH using a novel exchanger system whereby Lycopodium clavatum is functionalized with carboxylate and glyoxime metal-ligand complexes. The new ligand exchangers were prepared using a reaction of diaminosporopollenin with various metal-ligand complexes of glyoxime and monocarboxylic acid. The sorptive behavior of these metal-ligand exchangers and the possibilities to remove and to recover selectively heavy metal cations using these systems are discussed on the basis of their chemical natures and their complexing properties.     

Sorption of Aromatic Amines on a New Ligand Exchanger of Sporopollenin-Bound Co2+ Ion

Abstract

The mechanism of ligand-exchange sorption of aromatic amines such as p-chloroaniline, p-toluidine, and p-nitroaniline as ligands on a Co²⁺-loaded ligand exchanger has been studied. The observed rate seems to be related to the rate of ligand sorption with the mobile phase and pH in the aqueous phase. The saturation capacity and binding constant of ligand sorption on the resin increase with increasing basicity of amines. The rate of attainment of equilibrium sorption of aromatic amines is seen to be nearly similar. Coupled with the fact that different concentrations of solution were employed, these results may be interpreted as indicating that particle diffusion is the rate-controlling step. On the contrary, film diffusion was not rate-controlling step in the ligand sorption process under the conditions employed. It is shown that the kinetic parameters measured in single component experiments provide good prediction behavior. The pH dependencies and sorption isotherms of aromatic amines on the resins were also studied.     

Application of modified clays in diazotization and azo coupling reactions in water

Diazotization and diazo coupling reaction of a series of aromatic amines and activated aromatic compounds over eco-friendly modified clay catalysts are described. The reaction was catalyzed by modified montmorillonite K-10 including Cu²⁺, Fe³⁺, and Zn²⁺ metal ions. The versatility of this method was checked by using various amines and phenols, which showed reasonable yields of products. These inexpensive, noncorrosive and reusable catalysts were found to exhibit bifunctional catalytic properties for diazotization and diazo coupling reactions. The catalysts could be reused several times without significant loss of their catalytic reactivity.     

A simple and versatile protocol for the preparation of functionalized heterocycles utilizing 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione

The reaction of ethyl benzoylpyruvate with phenyl isothiocyanate in alkaline medium yields 4-benzoyl-5-phenylamino-2,3-dihydrothiophene-2,3-dione (1). Reaction of the intermediate 1 with primary aromatic amines such as aniline derivatives, benzidine and secondary aliphatic amines, namely diethylamine, piperidine, morpholine and piperazine afforded the corresponding thiophene 2a–2g and amide 3a–3d derivatives. Compound 1 reacts with N,N′- and N,O-dinucleophiles such as 1,2-diaminoalkanes, 2-aminoethanol, 1-aminoguanidine, guanidine, urea, 1,2-phenylenediamine and 2-amino-4-methylphenol to form the heterocylic compounds 4–10.     

Copper‐Catalyzed Oxybromination and Oxychlorination of Primary Aromatic Amines Using LiBr or LiCl and Molecular Oxygen

Nuclear oxybromination of unprotected aromatic primary amines catalyzed by copper(II) acetate [Cu(OAc)₂] under mild conditions has been developed, in which bromide ions are used as halogenating agents and dioxygen as a final oxidant. The catalyst shows not only high regioselectivity for para‐ or ortho‐isomers but also a remarkable chemoselectivity for monobromination. Oxychlorination of aniline can also be performed under similar conditions, albeit with lower selectivities, with N‐phenylacetamide being the main by‐product. This simple catalytic method represents ecologically benign and economically attractive synthetic pathway to expensive low‐volume aromatic haloamines.     

Double Metal Cyanides as Efficient Solid Acid Catalysts for Synthesis of β-Amino Alcohols Under Solvent-Free Conditions

A novel application of Fe–Zn double metal cyanide complexes as solid, acid catalysts for regioselective synthesis of β-amino alcohols under solvent-free conditions via ring-opening of epoxides with amines is reported for the first time. The conversion of epoxides to β-amino alcohols is nearly 100%. In the reaction with styrene oxide, regioselective β-amino alcohol formation is higher with aromatic than with aliphatic amines. Strong Lewis acidic Zn²⁺ ions in the catalyst are probably the active sites in this reaction.     

Synthesis,metal ion complexation and antibacterial activities of some thiapodands with lipophilic amide and ester end groups

A series of acyclic analogues of thiacrown ethers (podands) 7–12 with lipophilic amide and ester end groups were synthesized in high yield and in a simple way. Their transition metal ions complexation was studied using a conductometric method in acetonitrile at 25°C. Podands 7 and 11 showed a continuous decrease in the molar conductances in their complexation with Ag⁺, Cu²⁺, Cd²⁺, Hg²⁺, Zn²⁺ and Pb²⁺ which begins to level off at a mole ratio of 1:1 podand to metal indicating the formation of a stable 1:1 complexes. On the other hand, podand 9 also showed the formation of 1:1 complexes with above metal cations except with Hg²⁺ ion, which formed a 1:2 podand-to-metal ratio complex. An influence of end groups on metal ion selectivity is evident. Podands having ethoxy end groups (podands 8, 10 and 12 exhibit pronounced metal ion selectivity over podands having amino end groups (podands 7, 9 and 11). Compounds 10 and 12 with dithiaethylene units and ethoxy end groups provide the best selectivity for Hg²⁺ and Ag⁺ ions. These results suggest that podands 10 and 12 could be useful for the selective removal of Hg²⁺ and Ag⁺ ions from industrial waste that may contain a variety of toxic heavy and transition metal ions. The in vitro antibacterial activity of the investigated compounds was tested against several microorganisms such as Bacillus subtilis (ATCC 6633), Micrococcus luteus (ATCC 10240), Staphylococcus aureus (ATCC 43300), Escherichia coli (ATCC 25922) and Enterobacter aerogenes (ATCC 13048). The antibacterial activity of podand 10 is significant for M. luteus and B. subtilis compared with other podands under investigation.     

EVALUATION OF LIQUID-LIQUID PARTITION COEFFICIENTS OF MULTTDENTATE AMINES BY SCALED PARTICLE THEORY

ABSTRACT

For some aliphatic and aromatic bidentate amines, e.g., ethylenedi-amine derivatives, which were used in the synergistic extraction system, the liquid-liquid partition coefficients (P) were measured between benzene and water phases and discussed together with other aliphatic and aromatic multidentate amines by using the scaled particle theory (SPT). The contributions of three kinds of Gibbs energies, i.e, the cavity formation energy (G¯_h), the dispersion energy (G¯_dis) and hydrogen-bonding energy (G¯_h), to the P values were successfully evaluated. The main factor to determine the P value was G¯_h (10–55 kJ/mol) in the aqueous phase, but the contributions of G¯_c (6–15 kJ/mol) and G¯_dis (6–28 kJ/mol) were not negligibly small.     

High Molecular Weight Pyridine Amines as Solvents for Uranium(VI) and Its Separation from Thorium

Abstract

Three high-molecular-weight pyridine amines, 5-(4-pyridyl)nonane, 2-hexylpyridine, and diphenyl-2-pyridylmethane, have been studied as components of solvent extraction systems. Results are presented to show the dependence of the uranium extraction coefficient (D _a ^o = [U_org]/[U_aq]) on equilibrium concentrations of hydrochloric, nitric, and sulfuric acid solutions with and without thiocyanate ions. The optimal conditions for the extraction have been carefully selected from an extensive and critical investigation of the various factors involved; e.g., the effects of diluents, concentration of the mineral acids, thiocyanate ions, salting and complexing agents, and the concentration of the solvents. The extraction mechanism and composition of the extracted complexes of uranium have been studied from partition and slope-analysis data. The results obtained give an orderly picture of the mechanism of extraction of uranium thiocyanate complexes (partly in relation to the hydration and solvation of the compounds extracted). Anomalous extraction behavior was observed at solvent concentrations greater than 0.05 M. The results have been interpreted on the basis of the formation of micelles of the salt molecules of the solvents. It has been shown that these pyridines will extract the metal efficiently and reversibly from dilute acid chloride, nitrate, and sulfate solutions containing thiocyanate. Common salts have no depressing effect on extraction. Distribution coefficients and separation factors of several metal ions, with respect to uranium(VI), are reported for the three mineral acid systems, and a method for the separation of thorium-234 from uranium is also described.     

Feasibility Studies on Palladium Extraction from Leach Liquors of Automotive Catalysts Using p-Diethylphosphonomethylthiacalix[6]arene

Feasibility studies for the recovery of Pd(II) from leach liquors of automotive catalysts using p-diethylphosphonomethylthiacalix[6]arene (1) and p-tert-butylthiacalix[6]arene (2) were conducted. Compound 1 was found to be a more efficient extractant than 2 for Pd(II) ions, indicating selective extraction of Pd(II) ions [E% = 98.4%] from the leach liquors. The majority of other metal ions present in the leached solution were not extracted except Zr(IV) ions [E% = 22%]. Stripping of the Pd(II) ions from the extractants was performed using acidic thiourea, thereby enabling the recycling of the extractants.     

Easy obtainment of three-dimensional coordination polymer of zinc 1,2,4,5-benzenetetracarboxylate with para-amino-pyridinium cations

Within a wide study on coordination polymers coming from 1,2,4,5-benzenetetracarboxylate combined with aromatic amines and first row transition metal ions, we isolated and characterized a peculiar tridimensional coordination polymer made by an anionic mesoporous scaffold of Zn(II)-benzeneteracarboxylate whose charge is balanced by included p-aminopyridinium cations stacked up along two quasi-perpendicular crystallographic directions. The particular features of the solid state structure, easily obtained in standard conditions, prompts a wider research of possible related derivatives.     

Chemical modification of polypropylene fibers grafted vinyl imidazole/acrylonitrile copolymer prepared by gamma radiation and its possible use for the removal of some heavy metal ions

The chemical modification of polypropylene (PP) fibers by graft copolymerization with vinylimidazole (VIm) and acrylonitrile (AN) was carried out using γ‐radiation. Preparation conditions, such as irradiation dose, comonomer concentration and composition and type of solvent, affecting the degree of grafting were investigated. The suitable diluent for obtaining reasonable graft VIm/AN copolymer yield was acetone. The higher grafted yield was achieved by increasing the amount of vinylimidazole in comonomer feed solution as well as irradiation dose. The derivatives of PP‐g‐P(VIm/AN) grafted fibers of different functional groups were obtained by treating the grafted fibers with various organic reagents containing reactive amino groups, such as sulpha‐drug compounds, aliphatic‐ and aromatic amines. Characterization of the obtained graft copolymers and their chemical treatments with different amines was also investigated. It was observed that the nitrile group in PP‐g‐P(VIm/AN) polymer undergoes simple addition reaction via nucleophilic interaction mechanism to produce the corresponding PP‐graft‐P(vinylimidazole/acrylomidine) derivatives. The ability of the grafted fibers and their treated forms to absorb some metal ions as Cd, Hg, and Pb from their individual and mixture solutions was evaluated. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009.     

Elution Behavior of Metal Ions with Mixed Glycine-Nitric Acid Eluents in Dowex 50W-X8 Column: Separation of Th(IV), Ce(IV), Bi(III), Fe(III), and Al(III)

Abstract

Distribution coefficients (K) determined by the batch technique in acidic glycine media using Dowex 50W-X8 cation exchanger (H⁺?form, 100–200 mesh size) revealed that this medium can effectively be employed to separate a number of tetravalent and trivalent metal ions from bivalent metal ions. In fixed glycine (0.40 M) and varying concentration of nitric acid (0.10 to 1.0 M), a number of mixtures containing two or three metal ions were resolved on columns using about 8 g of exchanger. In 0.40 M glycine-1.0 M HNO₃ medium, Th(IV)/Ce(IV) were separated from Al(III)/Fe(III)/Bi(III)/Co(II)/Ni(II)/Cu(II)/Zn(II)/Cd(II)/Hg(II)/Pb(II)/Ag(I) and also Al(III)/Bi(III) from a number of divalent metal ions. In 0.40 M glycine-0.50 M HNO₃ medium, the resolution of following ternary mixtures were also achieved: Th(IV)/Ce(IV)-Al(III)/Bi(III)-Fe(III)/Co(II)/Ni(II)/Cu(II)/Zn(II)/Cd(II)/Hg(II)/Pb(II)/Ag(I). Th(IV)/Al(III)/Fe(III)/Bi(III) were also separated from other divalent metal ions in 1.60 M glycine-0.50 M HNO₃ medium. The values of K, elution characteristics of metal ions, elution curves, and the results of the resolution of a number of mixtures of metal ions along with standard deviations are reported.     

SOLVENT EXTRACTION OF THE RARE-EARTH METAL IONS BY A CONE-SHAPED CALDC[4]ARENE SUBSTITUTED AT THE LOWER RTM BY FOUR -CH2P(O)Ph2 LIGANDS

ABSTRACT

The extraction properties of cone-5,11,17,23-tetra-t-butyl-25,26,27,28-tetrakis(diphenylphosphinoylmethoxy)calix[4]arene (1) in 1,2-dichloroethane towards rare-earth metal ions at 25 °C have been investigated. The slope analysis showed a 1:1 metal/ligand ratio for the extracted species (La, Eu, Er and Y). The distribution coefficients increase with the polarity of the diluents : chloroform ≤ dichioromethane ≤ 1,2-dichloroethane ≤ nitrobenzene. In the competitive extraction of 11 rare-earth metal ions (La, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb and Y), ligand 1 exhibits higher extraction efficiency and a better separation factor than tri-n-octylphosphine oxide.     

Studies on Thorium Phosphate Ion Exchanger. Part III. Paper Chromatographic Behavior and Separations of Metal Ions on Thorium Phosphate Papers

Abstract

Thorium phosphate papers have been prepared by treatment with thorium nitrate and phosphoric acid solutions. Several metal ions have been chromatographed on thorium phosphate paper. The effect of pH on R_F values has been investigated. Some useful analytical separations of metal ions have been achieved by using only dilute mineral acid and a mixed solvent system.     

Specific Separation of Gallium,Gold, and Magnesium,and Separation of Be-AI-Ga on Stannic Molybdate Papers

Abstract

Chromatography of 47 cations in 11 solvent systems has been performed on stannic molybdate ion exchange papers. Some difficult separations, e.g., Rb from Cs, Al-Be-Ga, and Tl-In, and specific separations of Ga, Au and Mg from numerous metal ions, have been achieved. R _F values of some common metal ions on these papers have been compared with R _F values of these cations on stannic tungstate and stannic phosphate papers. The preparation of papers is easy and the results are reproducible.     

Studies on Stannic Selenoarsenate. II. Separation of Uranium from Numerous Metal Ions

Abstract

Stannic Selenoarsenate has been synthesized by adding 0.05 M sodium selenite and 0.05 M sodium arsenate to a 0.05 M solution of stannic chloride in a volume ratio of 1:1:1 at pH 1. A tentative structure has been proposed on the basis of chemical composition, pH titrations, and infrared and thermogravimetric analyses. Distribution coefficients of several metal ions have been studied in hydrochloric acid, citric acid, ammonium citrate-citric acid, and water-dioxane systems. The unusual adsorption behavior of uranium has been utilized for its quantitative separation from several metal ions.     

C,N‐Pyridylpyrazole‐Based Ligands: Synthesis and Preliminary Use in Metal Ion Extraction

Abstract

The synthesis of new N‐donor pyridylpyrazole ligands with a functionalized arm is described. The complexation capabilities of these compounds towards bivalent metal ions (Hg²⁺, Cd²⁺, Pb²⁺, Cu²⁺, and Zn²⁺) and alkali metal ions (K⁺, Na⁺, and Li⁺) were investigated using the liquid‐liquid extraction process. The percentage limits of extraction were determined by atomic absorption measurements.     

Arylphosphonate-Tethered Porphyrins: Fluorescence Silencing Speaks a Metal Language in Living Enterocytes**

We report the application of a highly versatile and engineerable novel sensor platform to monitor biologically significant and toxic metal ions in live human Caco-2 enterocytes. The extended conjugation between the fluorescent porphyrin core and metal ions through aromatic phenylphosphonic acid tethers generates a unique turn off and turn on fluorescence and, in addition, shifts in absorption and emission spectra for zinc, cobalt, cadmium and mercury. The reported fluorescent probes p-H₈TPPA and m-H₈TPPA can monitor a wide range of metal ion concentrations via fluorescence titration and also via fluorescence decay curves. Cu- and Zn-induced turn off fluorescence can be differentially reversed by the addition of common chelators. Both p-H₈TPPA and m-H₈TPPA readily pass the mammalian cellular membrane due to their amphipathic character as confirmed by confocal microscopic imaging of living enterocytes.