- Functionalized phosphonium based ionic liquids: Properties and application in metal extraction
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The extraction of Cu(ii), Zn(ii), Co(ii), Ni(ii) and Pb(ii) from model aqueous solutions using phosphonium based ionic liquids as sole extraction agents has been explored. The hydrophobic trioctyl(4-vinylbenzyl) phosphonium chloride, [P888(4-VB)/sub
- Barsanti, Alessandra Caterina,Chiappe, Cinzia,Ghilardi, Tiziana,Pomelli, Christian Silvio
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- Two novel lineal d10 metal-organic frameworks with a ditopic flexible linker: Structures, blue luminescence and thermal stability
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Two novel supramolecular Ag(I) complexes, {[AgL]NO3}n (1), and {[AgL]CF3SO3}n (2), (L) = ethane-1,2-diyl bis(pyridine-3-carboxylate) have been prepared by self-assembly of Ag(I) salts with ethane-1,2-diyl bis(pyridine-3-carboxylate) (L) in THF/H2O system. The IR, TGA and elemental analysis have been recorded and both complexes were structurally characterized by X-ray crystallography confirming that complexes (1) and (2) are one-dimensional coordination polymers with lineal and helical chain motifs respectively. Solid emission spectra at room temperature of (1) and (2) show interesting blue phosphorescence with maximum intensity at 414 and 411 nm respectively, which are assigned to (LLCT) transition.
- Brito, Iván,Vallejos, Javier,Cárdenas, Alejandro,López-Rodríguez, Matías,Bolte, Michael,Llanos, Jaime
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- Excited state properties of silver(I) nitrite complexes: Nitrogen conproportionation in Ag(NH3)NO2 induced by LLCT excitation
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The complex Ag(NH3)NO2, which can be viewed as a ligand-based mixed-valence compound, undergoes a photoconproportionation of nitrogen from -III and +III to 0. It is suggested that this photolysis originates from a NH3 to NO2- LLCT state which is populated from a NO2- IL state. In this context, the excited state properties of AgNO2 and Ag(H2O)NO2 are also discussed.
- Kunkely, Horst,Vogler, Arnd
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p. 784 - 786
(2008/10/09)
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- Evidence for dissociative photosubstitution reactions of [Ru(trpy)(bpy)(NCCH3)]2+. Crystal and molecular structure of [Ru(trpy)(bpy)(py)](PF6)2·(CH3) 2CO
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In acetonitrile and in the presence of appropriate nucleophiles, the complex [Ru(trpy)(bpy)(NCCH3)]2+ undergoes a ligand substitution reaction when irradiated into the metal-to-ligand absorption band system. (The symbol trpy denotes 2,2′:6′,2″-terpyridine, and bpy denotes 2,2′-bipyridine.) At 25°C quantum yields for displacement of the acetonitrile ligand are 0.0013 (1), 0.0013 (1), and 0.0026 (5) for 1.0 M solutions of pyridine, 4-phenylpyridine, and 2-methylpyridine, respectively. No photochemistry is observed for the osmium(II) analogue, and all findings can be understood in terms of a dissociative reaction mechanism involving a reactive 3d-d state. The 3d-d state is accessed from a 3CT state, which is emissive below ca. 180 K. From measurements of the temperature dependence of the emission lifetime, the barrier to population of the 3d-d state is approximately 1500 cm-1. Finally, the crystal structure of [Ru(trpy)(bpy)(py)](PF6)2·(CH3) 2CO has been determined with a diffractometer. The compound crystallizes with two independent formula units in a triclinic unit cell. The space group is P1, and there are four formulas per unit cell (Z = 4) with a = 13.150 (1) A?, b = 14.927 (1) A?, c = 19.771 (2) A?, α = 102.840 (9)°, β = 91.655 (8)°, and γ = 103.371 (8)°. The structure was solved by the full-matrix least-squares method, and after the final stage of refinement, R = 0.055. There is evidence of interligand steric strain within the coordination sphere, and the bpy ligand is coordinated asymmetrically with a difference in Ru-N bond lengths of about 0.04 A?. The internal strain probably explains why we have been unable to prepare the 2-methylpyridine analogue by standard methods.
- Hecker, Clark R.,Fanwick, Phillip E.,McMillin, David R.
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p. 659 - 666
(2008/10/08)
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- Hydrates of Organic Compounds. VII. The Effect of Anions on the Formation of Clathrate Hydrates of Tetrabutylammonium Salts
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Phase diagrams of the binary mixtures of tetrabutylammonium salt nX (X = NO2, NO3, BrO3, ClO3, IO3, ClO4, MnO4, and NCS for n = 1; X = CO3, SO4, WO4, and CrO4 for n = 2; and X = PO4 for n = 3) with water were determined over the temperature range between -10 and +50 deg C.From these diagrams the following results were obtained: (1) the formation of a clathrate-like hydrate for salts having such anions as NO2-, NO3-, BrO3-, ClO3-, IO3-, SO42- and PO43- was newly confirmed; (2) the melting point of the clathrate hydrate of the salt with monovalent anion was appreciably influenced by the kind of anion; (3) in the hydrates of the salt having either di- or trivalent anions, the melting points were relatively high and were only slightly affected by the kind of anion; (4) the crystal structure of these hydrates was essentially the same as that of the tetrabutylammonium fluoride hydrate, judging from the hydration numbers; (5) the solubilities in water of both permanganate and perchlorate were markedly lower than that of the iodide; and (6) in the thiocyanate system a phase separation into two liquid phases was observed at temperatures higher than +3.5 deg C.The effect of a monovalent anion on the stability of the clathrate hydrate was discussed in connection with the conventional partial molal volume of the anion.
- Nakayama, Haruo
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p. 877 - 880
(2007/10/02)
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