A new [Cu(ox)(Im)2] complex resulting from the oxidation of chelidonate to oxalate (original) (raw)
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Copper(I) oxalate complexes: Synthesis, structures and surprises
Polyhedron, 2016
A series of dinuclear copper(I) oxalate complexes was synthesized by the direct acid-base reaction of Cu2O with oxalic acid in ethanol with a ligand, or in neat ligand. The complexes incorporated a variety of ligands L (L = triphenylphosphine, 1,2bis(diphenylphosphino)ethane, triphenylphosphite, diisopropyl sulfide, cyclooctadiene and cyclohexylisocyanide) and had the general formula LnCu(µ2-C2O4)CuLn (n = 1 or 2). The Cu I /Cu II mixed-valence trinuclear compound (iPr2S)2Cu I (C2O4)Cu II (C2O4)Cu I (iPr2S)2 was formed concomitantly with the target dinuclear Cu2C2O4(iPr2S)4 complex, shedding light on the mechanism of disproportionation of this family of complexes. With norbornadiene (nbd) as a ligand, however, a coordination polymer Cu2C2O4(nbd) was formed. Also, the same reaction with L = 2,9-dimethyl-1,10-phenanthroline or pyridine resulted in the known tetrahedral complex ions [CuLm] + (m = 2 or 4). Lastly, the ligand di-2-(1-di-(2-picolyl)amino)propyl 3 disulfide produced not the expected Cu(I) oxalate complex, but a Cu(II) picolylamine oxalate coordination polymer. All products were structurally characterized by single-crystal X-ray diffraction if soluble, and by powder X-ray diffraction methods if not.
Oxalato complexes of copper(II) with chelating diamines. Crystal structure of [Cu(dmen)ox(H2O)]2Cu(dmen)22
Polyhedron, 2002
Four new oxalato complexes of copper(II) of composition [Cu(dmen)ox(H 2 O)] 2 [Cu(dmen) 2 ](ClO 4 ) 2 (1) (dmen 0/N ,Ndimethylethylenediamine, H 2 ox0/oxalic acid), [(Cu(dmen)H 2 O) 2 ox](ClO 4 ) 2 ×/H 2 O (2), [Cu(tmen)(H 2 O)(ox)Cu(aep)(H 2 O)](ClO 4 ) 2 (3) (tmen 0/N ,N ,N ?,N ?-tetramethylethylenediamine, aep0/2-(2-aminoethyl)pyridine) and [(Cu(dben)NO 3 ) 2 ox] (4) (dben 0/N ,N ?dibenzylethylenediamine) have been prepared and characterised by IR and UV Á/Vis spectroscopies and magnetic measurements. The crystal structure of [Cu(dmen)ox(H 2 O)] 2 [Cu(dmen) 2 ](ClO 4 ) 2 (1) has been determined by single-crystal X-ray analysis. The structure of 1 contains a neutral [Cu(dmen)ox(H 2 O)] complex, a cationic [Cu(dmen) 2 ] 2' complex and perchlorate anions. The copper(II) atom of the neutral [Cu(dmen)ox(H 2 O)] unit possesses a distorted square-pyramidal environment with two oxygen atoms of oxalate and two nitrogen atoms of dmen in the basal plane and an oxygen atom of a water molecule in the apical position. The copper(II) atom of the cationic [Cu(dmen) 2 ] unit shows a square-planar environment with four donor nitrogen atoms of two molecules of dmen. The temperature dependence of magnetic susceptibility for compounds 2 Á/4 was measured. Magnetochemical measurements show that copper(II) ions in compounds 2 Á/4 are antiferromagnetically coupled through the oxalate bridge, J 0/ (/157, (/175 and (/167 cm (1 (H 0/(/2JS 1 S 2 , S 1 0/S 2 0/1/2) for 2, 3 and 4, respectively. #
Inorganic Chemistry, 1992
mononuclear complexes that we have isolated as tetra-and pentahydrate sodium salts, respectively. The synthesis of M2L complexes was carried out in the light of the respective distribution diagrams based on fitted equilibrium constants (Figures 4 and 5). In order to obtain single crystals of such species, aqueous solutions of copper(I1) nitrate (nickel(I1) nitrate) and H4L in a 2: 1 molar ratio were prepared a t p H = 3. In the case of copper(II), the slow polymerization of Cu(H2L) leads to the insoluble polymeric complex 1. Nevertheless, Cu2-L.6H20 can be isolated as a powder in weakly acidic aqueous solutions. The nonpolymerization of the Ni(H2L) species allows in this case the formation of single crystals of the insoluble complex 2 in nearly neutral aqueous solutions. Conclusions. The versatility of N,N'-disubstituted oxamides has allowed the synthesis of mono-, di-, and polynuclear complexes. Strong antiferromagnetic coupling is observed in the poxamidato polynuclear compounds. This work shows how one must be careful when using the n21J1 values to estimate the magnitude of the exchange coupling in binuclear nickel(I1) complexes from the known values for the corresponding copper(I1) complexes through a given bridge. Although nickel(II)-oxamide complexes are usually diamagnetic, paramagnetic nickel(11) species can be obtained by tuning the strength of the ligand field using as tools appropriate N-substituted derivatives and angular strain. Finally, this report provides a new example of complementarity between solution and solid-state studies, showing how solution data can orientate the synthetic work in order to obtain the desired products. Acknowledgment. This work was partially suppprted by the Comisidn Interministerial de Ciencia y Tecnologia (Proyecto PB88-0490) and the Programa de Acciones Integradas Hispano-Francesas. R.R. acknowledges the Conselleria de Cultura, Educacid i C i h c i a de la Generalitat Valenciana for a grant.
Synthesis, Crystal Structure and Spectroscopic Properties of an Oximato Bridged Cu(II) Dimer
Journal of Chemical Crystallography, 2011
Schiff-base condensation of a equimolar proportion of diacetyl-monoxime monohydrazone and 1-methylimidazole-2-carboxaldehyde in methanol gives rise to the imidazole azine, 3-(1-methylimidazol-2-yl)methylenehydrazonobutan-2-one oxime(HL). Reaction of 1:1 stoichiometric proportion of HL with copper(II)perchlorate hexahydrate in methanol yields a dimeric oximato bridged copper compound, [Cu 2 L 2 (H 2 O) 2 ](ClO 4 ) 2 (1). The compound is characterized by C, H and N analyses, FT-IR, ESI-MS, conductivity measurement, UV-Vis spectra and X-ray single crystal diffraction. The title compound (1) crystallizes in the monoclinic space group P2 1 /c with a = 6.8533 (8), b = 18.413 (2), c = 11.7399 (14) Å , b = 93.685 (2)°, V = 1478.4 (3) Å 3 and Z = 2. The geometry around each copper center is distorted square pyramidal. The copper(II) dimer shows antiferromagnetic interaction mediated by symmetric disposition of oximato groups.
Acta Crystallographica Section E Crystallographic Communications
Two CuII complexes [Cu(C14H13N4O2)Cl] n , I, and [Cu4(C8H10NO2)4Cl4] n , II, have been synthesized. In the structure of the mononuclear complex I, each ligand is coordinated to two metal centers. The basal plane around the CuII cation is formed by one chloride anion, one oxygen atom, one imino and one pyridine nitrogen atom. The apical position of the distorted square-pyramidal geometry is occupied by a pyridine nitrogen atom from a neighbouring unit, leading to infinite one-dimensional polymeric chains along the b-axis direction. Each chain is connected to adjacent chains by intermolecular C—H...O and C—H...Cl interactions, leading to a three-dimensional network structure. The tetranuclear complex II lies about a crystallographic inversion centre and has one core in which two CuII metal centers are mutually interconnected via two enolato oxygen atoms while the other two CuII cations are linked by a chloride anion and an enolato oxygen. An open-cube structure is generated in which t...
Molecules
Five new copper(II) acrylate complexes (acr is the acrylate anion: C3H3O2) with imidazole derivatives (2-methylimidazole/2-MeIm, 5-methylimidazole/5-MeIm, 2-ethylimidazole/2-EtIm) of type: cis-[Cu(2-RIm)2(acr)2]·xH2O ((1): R = –CH3, x = 2; (4): R = –CH2–CH3, x = 0), trans-[Cu(2-RIm)2(acr)2] ((2): R = –CH3; (5): R = –CH2–CH3) and trans-[Cu(5-RIm)2(acr)2] ((3): R = –CH3) have been prepared and characterized by elemental analysis, Fourier Transform Infrared spectrometry (FTIR), Electron Paramagnetic Resonance (EPR), electronic reflectance spectroscopy, scanning electron microscopy, and mass spectrometry. The single crystal X-ray diffraction study of complexes (2) and (5) reveals that the copper(II) ion is located on an inversion center and show elongated octahedral geometry completed by two coplanar bidentate acrylates and two unidentate imidazole derivatives displayed in trans positions. For complex (4) the single crystal X-ray diffraction shows that the copper(II) ion is in a distort...
Inorganic Chemistry Communications, 2009
The use of 1,1 0 -oxalyldiimidazole, (im)COCO(im), for the synthesis of coordination complexes is explored for the first time. The [Cu 2 (O 2 CMe) 4 (H 2 O) 2 ]/(im)COCO(im) reaction system in 96% EtOH yields the new, 1D coordination polymer [Cu(ox)(Him) 2 ] n (1), where Him is the neutral imidazole and ox 2À is the oxalate(-2) ligand. A mechanism for the hydrolytic decomposition of the ligand is proposed. Complex 1 comprises neutral, zigzag chains with the g 1 :g 1 :g 1 :g 1 :l (2.1111 using Harris notation) ox 2À ligand bridging two neighboring Cu II centers; two cis Him groups complete a Jahn-Teller distorted octahedral geometry at the metal. The dc, variable-temperature magnetic susceptibility data for the complex reveal antiferromagnetic Cu II Á Á ÁCu II exchange interactions.