- Structural insights into the usage of carboxylate ions as molecular pins
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Two series of new isostructural coordination compounds containing cobalt, nickel, copper butyrates (butyr) or isobutyrates (ibutyr) and 1,10-phenanthroline (phen), of general formulas [M(phen)3]2+·2(butyr?)·11H2O and [M(phen)3]2+·2(ibutyr?)·14H2O, were synthesized in water solutions and characterized by X-ray crystallography, IR, UV–Vis and fluorescence spectroscopy, elemental and thermal analysis. The carboxylate anions are located in an outer coordination sphere, which is a unique phenomenon in case of ibutyr coordination compounds. The studied compounds exhibit layered packing in crystal net. The “aqueous layers” consist of water molecules and carboxylate groups of carboxylate anions, assembled via hydrogen bonds to the two dimensional supramolecular networks containing multiple different cyclic motifs. Coordination units together with aliphatic ends of carboxylate anions form the “coordination moieties layers”, which are internally connected via π?π and C–H?π intermolecular interactions. The carboxylate anions function as supramolecular linkers between these layers and allow pinning them together. The spectroscopic and thermal properties have been discussed and correlated with molecular structures of the studied compounds. Due to placement of carboxylate anions out of coordination moieties, the presented compounds can be ideal standards in spectroscopic determinations of coordination type of butyr and ibutyr ions in coordination compounds. The thermal analyses of the studied compounds revealed the possibility of formation of dihydrate forms, and such dihydrated compounds cannot be produced in direct synthesis performed in aqueous media. In properly set environment the studied compounds can be thermally converted to micro- and nanoparticles of respective metal oxides.
- Swiatkowski, Marcin,Kruszynski, Rafal
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p. 265 - 277
(2017/08/10)
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- Thermal evolution of ceramic powders surrounding the YBa2Cu 3O7-x composition
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Organometallic-derived ceramic compositions surrounding YBa 2Cu3O7-x (123) were evaluated via DTATG runs and dilatometric densification. The compositions were either Y, Ba or Cu deficient respect to 123. For the Yttrium de
- Benavidez, Edgardo R.,Gonzalez Oliver, Carlos J. R.
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p. 369 - 375
(2010/09/06)
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- METHOD FOR THE PRODUCTION OF METAL CARBOXYLATES AND THE METAL AMINOATE OR METAL HYDROXY ANALOGUE METHIONATE DERIVATIVES THEREOF, AND USE OF SAME AS GROWTH PROMOTERS IN ANIMAL FEED
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A method of production of metal carboxylates and of their metal carboxylate-aminoate or metal carboxylate-methioninate hydroxy analog derivatives, and their use as growth promoters in animal nutrition. It comprises mixing stoichiometric quantities of formic or butyric acid and oxide and of the dry basic salt of divalent metal, the oxide or hydroxide of Zn2+ or Cu2+, to give an exothermic reaction, without addiction of solvents, giving rise to a dry carboxylate of divalent metal that is easy to use. It also describes the use of a stage of mixing with metal aminoates or hydroxy analogs of methionine in the process, for forming either a carboxylate-aminoate of divalent metal or a carboxylate-methioninate hydroxy analog of divalent metal, products that are finally obtained in a dry form that is easy to use. Finally it describes the use of the compounds that can be obtained in the feeding of monogastric animals for improving the productivity, the bioavailability of the metals, and achieve a reduction of their emission to the environment, owing to the growth-promoting effect that they all display.
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Page/Page column 5-6
(2008/06/13)
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- One-dimensional and two-dimensional coordination polymers from self-assembling of trinuclear triangular cu(II) secondary building units
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The reactions of pyrazole (Hpz) with some copper(II) carboxylates in the presence of water yield trinuclear copper derivatives characterized by the triangular core [Cu3(μ3-OH)(μ-pz) 3(RCOO)2] (R = H, C2H5, C 3H7). Copper(II) formate gives [Cu3(μ 3-OH)(μ-pz)3(HCOO)2(Hpz)2] (1), whereas copper propionate and butyrate afford [Cu3(μ3- OH)(μ-pz)3-(C2H5COO)2(EtOH)] (2) and [Cu3(μ3-OH)(μ-pz)3(C 3H7COO)2(MeOH)(H2O)] (3), respectively, both containing solvent molecules coordinated to copper atoms. Magnetic susceptibilities are consistent with a single unpaired electron for each trinuclear unit of 1-3, and EPR measurements indicate that higher spin states, generated by exchange coupling between copper atoms, may be populated at room temperature. Density-functional calculations provide the description of the electronic structures of 1-3, allowing, at the same time, the assignment of their UV-vis absorption spectra. X-ray molecular structure determinations show that triangular trinuclear units of 1 are connected to each other through single formate bridges, forming one-dimensional (1D) zigzag coordination polymers, whereas in 2 and 3, two oxygen atoms of two carboxylate ions doubly bridge two copper atoms of different triangles, thus generating hexanuclear units. Moreover, in 2, two other propionate ions link together two hexanuclear units yielding a 12-membered cycle and giving rise to 1D coordination polymers. The supramolecular assemblies of 1-3 are compared to that of the previously reported trinuclear triangular copper(II) derivative [Cu3(μ3- OH)(μ-pz)3(CH3COO)2-(Hpz)] (A), where a two-dimensional (2D) coordination polymer is present. The reactions of 3,5-dimethylpyrazole (Hpz*) with copper(II) carboxylates in the same conditions yield 1:2 Cu(RCOO)2/Hpz* adducts.
- Casarin, Maurizio,Corvaja, Carlo,Di Nicola, Corrado,Falcomer, Daniele,Franco, Lorenzo,Monari, Magda,Pandolfo, Luciano,Pettinari, Claudio,Piccinelli, Fabio
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p. 6265 - 6276
(2008/10/09)
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- Effect of synthesis method of nanocopper catalysts on the morphologies of carbon nanofibers prepared by catalytic decomposition of acetylene
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Carbon fibers, prepared by metal-catalyzed decomposition of hydrocarbons, e.g., acetylene, benzene, and methane, present various growth models including whisker-like, branched, bi-directional, and multidirectional types of growth. The addition of additives or a second metal to the metal catalyst, the use of a support, the pretreatment of the catalyst, and the catalyst source may have considerable effects on carbon deposition. Carbon nanofibers were synthesized by the decomposition of acetylene with nanocopper catalysts to determine the effects of synthesis method on the morphologies of carbon nanofibers obtained. Copper nanoparticles catalyzed the carbon deposition of acetylene to yield regularly coiled fibers with a novel symmetric growth type, whereas ribbon-like fibers formed over nanocopper particles prepared by hydrogen-arc plasma method. The copper nanocrystals changed from irregular or spherical shape to faceted shapes after fiber growth. The regularity of the shapes of the faceted catalyst particles included in the fibers accounted for the different morphologies of the resulting products.
- Qin, Yong,Zhang, Qian,Cui, Zuolin
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p. 389 - 394
(2008/10/09)
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- Decomposition of organic salts of some d and f metals: Non-isothermal kinetics and FT-IR studies
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The thermal decomposition in non-isothermal conditions of formates, acetates, propionates and butyrates of Mn, Co, Zn, Cd, Eu, Sm and Ni was studied. The observed compensation effect allows us to calculate the isokinetic temperature. A selective activation mechanism was suggested. This leads to a good agreement between kinetic and spectroscopic data.
- Vlase,Vlase,Chiriac,Doca
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p. 839 - 845
(2008/10/08)
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- Structure-Magnetism Correlation in Dimeric Copper(II) Carboxylates: Crystal and Molecular Structure of Tetra-μ-(propanoato-O,O')-bis(aquacopper(II))
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The dimeric copper(II) carboxylates 2> and 2> (R=Et or Prn)) have been prepared and characterized by means of spectroscopic, magnetic, and thermogravimetric analyses.For 2> the crystal and molecular structure has also been determined.The crystals are monoclinic, space group P21/c, with a=15.102(7), b=17.186(5), c=15.190(4) Angstroem, β=94.24(3) deg, and Z=4.Full-matrix least-squares refinement, using 1784 independent reflections converged to a conventional R factor of 0.0561.The unit cell contains four crystallographically independent copper(II) atoms which give rise to three binuclear molecules with copper(II) acetate monohydrate type geometry.Two of these dimers are centrosymmetric with the symmetry centre at the middle of the Cu-Cu bond.Comparison of the present structural data and values with those of other structurally known dimeric copper(II) alkanoates does not allow an unambiguous determination of a specific ligand parameter to be the major factor in determining the magnitude of , and suggests that it may be the result of several modes of interaction.
- Battaglia, Luigi Pietro,Corradi, Anna Bonamartini,Menabue, Ledi
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p. 1653 - 1658
(2007/10/02)
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