Search results for "COPP"
showing 10 items of 3147 documents
Synthesis, structural characterization and electrochemical and magnetic studies of M(hfac)2 (M = CuII, CoII) and Nd(hfac)3 complexes of 4-amino-TEMPO
2020
Three mononuclear complexes [M(hfac)x(ATEMPO)y], where M = Cu (11) and Co (12), x = y = 2; M = Nd (13), x = 4, y = 1, and two polynuclear complexes [{Cu(hfac)2(ATEMPO)}n], where n = 2 (14) and 4 (15), were obtained by the reaction of M(hfac)x (M = CuII, CoII, NdIII; x = 2, 3) with 4-amino-TEMPO (4-amino-2,2,6,6-tetramethylpiperidin-N-oxyl) in good yields and their structural, electrochemical and magnetic properties were examined. In all cases, the radical is coordinated to the metal through the amino group, except 15, and the metal ions have an octahedral geometry, except 13. Different coordination architectures of the copper complexes were obtained as a function of the stoichiometry and so…
Gas-phase hydrogenation of propionitrile on copper-lanthanide oxides
2009
Abstract The hydrogenation of propionitrile on copper-lanthanide oxide catalysts (2Cu·CeO 2 and 4Cu·Ln 2 O 3 (Ln = La, Pr, Nd)) was studied in the gas phase. The activity of the catalysts varies with the lanthanide in the order 2Cu·CeO 2 > 4Cu·Pr 2 O 3 > 4Cu·La 2 O 3 ≥ 4Cu·Nd 2 O 3 , while the activation energies varies in the opposite order, except for 2Cu·CeO 2 . The main product was the primary amine, n -propylamine. The formation of the unstable imine CH 3 CH 2 N CHCH 3 as a major product over 2Cu·CeO 2 seems to be consistent with the acidity of the catalyst. The catalysts were more selective than conventional copper impregnation catalysts, Cu (10 wt.%) on SiO 2 , La 2 O 3 or CeO 2 ,…
Magnetic order in a CuII–DyIII oxamato-based two-dimensional coordination polymer
2019
Abstract We report the synthesis, crystal structure, and magnetic characterization of a novel two-dimensional copper(II)–dysprosium(III) coordination polymer of formula [LiI(OH2)4]2[DyIIICuII2(Me2pma)4Cl(H2O)] . 4H2O (1) [Me2pma = N-2,6-dimethylphenyloxamate]. Compound 1 was obtained using the mononuclear anionic complex [CuII(Me2pma)2]2–, as a bis(bidentate) metalloligand toward solvated dysprosium(III) cations, and it shows a square [DyIIICuII2] layered structure of (44.62) net topology. Interestingly, the combination of two factors, the well-known efficiency of oxamato ligands to transmit strong magnetic couplings between neighboring atoms and such structural topology, is responsible for…
Sozialformen
2010
Il testo presenta una visione complessiva delle varie forme di lavoro in classe che contraddistinguono le lezioni di lingua straniera.
Heavy metal sorption in the lichen cationactive layer.
2007
Results of copper ion sorption in lichens owing to the ion exchange between the surroundings (aqueous solution) and the lichen cationactive layer have been presented. It indicates that the course of sorption of these ions, similarly as in the case of cations of other heavy metals, depends on the concentration and type of cations naturally found in lichen surroundings: H+, Na+, K+, Mg2+ and Ca2+. A determination method of heavy metal concentration in lichen surroundings has been proposed. It consists in exposure of transplanted lichens in the presence of salts that provide precisely determined, artificial salinity of precipitation with which the lichens are in contact. The studies were condu…
Crystal structure and spectroscopic studies of bis(N-2-pyridinylcarbonyl-2-pyridinecarboximidato)copper(II) monohydrate. Local bonding effects
1989
Abstract The crystal and molecular structure of bis(N-2- pyridinylcarbonyl-2-pyridinecarboximidato)copper(II) monohydrate, Cu(BPCA)2·H2O, has been determined from single crystal X-ray data. It crystallizes in the monoclinic space group P21/c with four formula units in a cell of dimensions: a = 8.917(1), b = 8.932(1), c = 28.794(17) A, β= 95.49(2)°.Least- squares refinement of 2754 reflections with I > 2.5σ(I) and 379 parameters gave a final R = 0.037 (Rw = 0.036). The structure consists of discrete neutral Cu(BPCA)2 entities linked two by two through water molecules hydrogen bonded to ligand carbonyl groups. The coordination geometry around copper ions can approximately be described as orth…
ChemInform Abstract: Crystal Structure and Spectroscopic Studies of Bis(N-2-pyridinylcarbonyl-2-pyridinecarboximidato)copper(II) Monohydrate. Local B…
1989
Abstract The crystal and molecular structure of bis(N-2- pyridinylcarbonyl-2-pyridinecarboximidato)copper(II) monohydrate, Cu(BPCA)2·H2O, has been determined from single crystal X-ray data. It crystallizes in the monoclinic space group P21/c with four formula units in a cell of dimensions: a = 8.917(1), b = 8.932(1), c = 28.794(17) A, β= 95.49(2)°.Least- squares refinement of 2754 reflections with I > 2.5σ(I) and 379 parameters gave a final R = 0.037 (Rw = 0.036). The structure consists of discrete neutral Cu(BPCA)2 entities linked two by two through water molecules hydrogen bonded to ligand carbonyl groups. The coordination geometry around copper ions can approximately be described as orth…
Factors affecting copper(II) binding to multiarmed cyclam-grafted mesoporous silica in aqueous solution
2009
Single- as well as multi-anchored cyclam-functionalized silica samples have been prepared by grafting amorphous silica gel (K60) and mesostructured silica (SBA-15) with silylated cyclam precursors bearing one, two, or four triethoxysilyl groups, respectively ascribed to cyclam-mono, cyclam-di, and cyclam-tetra. Their reactivity toward copper(II) has been thoroughly investigated in aqueous solution and discussed with respect to the number of arms tethering the ligand to the silica surface and the structural ordering of the adsorbent in terms of capacity, long-term stability, and speed of access to the binding sites. Less-than-complete metal ion uptake was always observed, even in excess of c…
A Simple Phosphine–Diolefin‐Promoted Copper‐Catalysed N‐Arylation of Pyrazoles with (Hetero)aromatic Bromides: The Case of Chloroarenes Revisited
2012
A molecularly defined new phosphine–diolefin cubane copper pre-catalyst used at 1.25 mol % under mild conditions promotes the coupling of pyrazoles to functionalised aryl and heteroaryl bromides, which hold a variety of functional groups. This versatile phosphorus-based system was thus successfully used, under identical conditions, for the coupling of a large scope of heteroaromatics to selectively produce pyridinyl- and pyrimidinyl-pyrazoles, as well as several novel furyl-, thienyl- and thiazolyl-substituted pyrazoles. The careful investigation of coupling with the analogous aryl and heteroaryl chlorides clearly indicated that for specifically activated chloroarenes a direct nucleophilic …
Mononuclear and binuclear copper(II) complexes with bis(2-imidazolyl)(bis(methoxycarbonyl)methylmethane) (BIBM), a tripodal bis(imidazole) based liga…
2013
Two new Cu(II) complexes with bis(2-imidazolyl) (bis(methoxycarbonyl)methylmethane) (BIBM), a tridentate bis(imidazole) based ligand with the formula [Cu(BIBM) 2 ](ClO 4 ) 2 ( 1 ) and [{Cu(BIBM)(H 2 O)} 2 (μ 1,2,3,4 -C 2 O 4 )](C 4 O 4 )·6H 2 O ( 2 ) have been synthesized and characterized. Compound 1 shows mononuclear cationic [Cu(BIBM) 2 ] 2+ units and perchlorate ions. The coordination around the Cu(II) ion shows a tetragonally-elongated octahedral geometry. The BIBM ligand acts as a k 3 -N,N’,O tripodal ligand, through two imidazole N atoms and a weak Cu–O(carboxymethyl) axial interaction. In the crystal structure cations and anions connect through H-bonds generating linear chains. Line…