- Syntheses, structures and electrochemical properties of two co-crystal copper(II) melamine complexes
-
Two new co-crystal copper(II) melamine complexes, [Cu(HBA)2(MA)2] [Cu(HBA)2] (1) and [Cu2(OAc)4(MA)·(H2O)]2[Cu(HPE)2] (2), MA, melamine; HBA, 2-hydroxybenzaldehyde; HPE, 1-(2-hydroxyphenyl)ethanone, have been synthesized and characterized by elemental analysis, IR and single crystal X-ray diffraction. Crystal structural analysis reveals that 1 and 2 all are co-crystal complexes and composed of two neutral coordination units. In 1, two mononuclear units adopt square planar and distorted octahedral coordination environments, respectively. In 2, one is a mononuclear unit with a square planar geometry and the other is a dinuclear unit with a paddle wheel structure in which the apical positions are rarely occupied by two different donor ligands. The 2D supramolecular structures are formed through strong hydrogen bonds with different modes. The electrochemical behaviors of complexes 1 and 2 were investigated.
- Xu, Li-Feng,Chen, Xiao-Li,Hu, Huai-Ming,Wang, Bao-Cheng
-
-
Read Online
- Copper(II)-salicylaldehydate/-methoxy(pyridine-2-yl)methanolate complexes via in-situ hydrolysis of Schiff bases
-
Reaction of copper(II) nitrate with N-2-(R-pyridyl)salicylaldimine affords the mononuclear bis[salicylaldehydato-κO,O′]copper(II) (1) via acidic hydrolysis of the aldimine ligand back to the salicylaldehyde. Similarly, reaction with (R)-N-1-(p-BrC6H4)ethyl-salicylaldimine or (R)-1-(p-BrC6H4)-N-((pyridin-2-yl)methylene)ethanamine in presence of 2,2′-bipyridine (bipy) provides the mixed-ligated dinuclear bis[(μ-salicylaldehydato-κO,O′:O′)(2,2′-bipyridine)nitrato-copper(II)] (2) or bis[{μ-methoxy(pyridine-2-yl)methanolato-κN,O:O}(methanol)nitrato-copper(II)] (3). The structures of 2 and 3 consist of a dinuclear unit involving two (bipy)(salicylaldehydate)- or {methoxy(pyridine-2-yl)methanolate}(methanol)-coordinated copper(II) cations and two nitrate anions. The coordination sphere of copper is of N2O4-type with an elongated octahedron due to the Jahn-Teller effect in 2. The axial positions of the square bipyramid are occupied by the oxygen atoms from NO3? and the phenoxo group of the nearest salicylaldehydate molecule. The coordination sphere of copper is of NO4-type in 3, with the alkoxido group of methoxy(pyridine-2-yl)methanolate bridging between the Cu atoms. Cyclic voltammograms for 1 demonstrate two quasi-reversible one electron charge transfer processes for [Cu(L)2]2?/[Cu(L)2]? and [Cu(L)2]?/[Cu(L)2] (L?=?salicylaldehydato), respectively in acetonitrile. DSC analyses reveal an irreversible phase transformation from solid to solid-liquid mixture phase, and then to an isotropic liquid phase for 1. The excited state properties of 1 studied by DFT/TDDFT are comparable to the experimental electronic spectrum.
- Enamullah, Mohammed,Chamayou, Anne-Christine,Banu, Kazi Saima,Kautz, Anna Christin,Janiak, Christoph
-
-
Read Online
- Synthesis and solid state structures of copper(II) complexes of Schiff bases derived from cyclopropyl and cyclobutylamine
-
The Schiff base copper(II) complexes (1)-(6) were prepared and characterised by mass, IR, and electronic spectra. Their solid states structures, determined by X-ray crystallography, indicate that the geometry around copper is determined by a combination of steric and electronic effects, as well as crystal packing forces. Thus, complex (1) is the only one in the series to have a square planar geometry. In contrast, complexes (2) and (3) display deformed square planar geometries, despite the small steric effect of the N-cyclopropyl and cyclobutyl groups. Furthermore, a purely electronic argument, based on which complexes (5) and (6) must have deformed tetrahedral structures, fails to account for the observed stepped square planar structures. Finally, complex (4) also has a stepped square planar geometry.
- Castillo, Ivan,Fernández-González, Juan M.,Gárate-Morales, José Luis
-
-
- Kinetics of Complex Formation of Inner-Complex Salts of Copper(II) with Porphyrins in Propanol
-
The kinetics of complex formation of the inner-complex salts of copper(II), CuL2 (HL is acetylacetone, 3-butyl-2,4-pentanedione, 3-benzyl-2,4-pentanedione, salicylaldehyde, and 3-formyl-5-tert-butylsalicylaldehyde), with (1-8)-alkylporphyrins are studied. The activation parameters for this reaction are calculated. It is shown that the reaction rate for the coordination of porphyrins with the Cu(2+) ion substantially depends on the nature of the anion in the case of organic salts.
- Berezin, B. D.,Trofimenko, G. M.,Semeikin, A. S.,Berezin, M. B.
-
p. 478 - 483
(2008/10/08)
-
- Complexes de Cu(II), Co(II), Ni(II) et UO2(II) avec les bases de Schiff N-(4-methyl-2-pyridyl)salicylaldimine et N-(6-methyl-2-pyridyl)salicylaldimine
-
We have isolated the complexes of the Schiff bases N-(4-methyl-2-pyridyl)salicylaldimine and N-(6-methyl-2-pyridyl)salicylaldimine with Co(II), Ni(II), Cu(II), and UO2(II) in both aqueous alcoholic and absolute alcoholic solutions.We note different modes of action of these Schiff bases according to the medium used.However, in aqueous alcoholic solution the complexes mentioned have a remarkable capacity for reaction with the substances in solution.We propose two new gravimetric methods for Ni(II) and UO2(II).
- Capitan-Vallvey, L. F.,Jimenez, C.,Cuadros, L.
-
p. 1713 - 1719
(2007/10/02)
-