Search results for "COPP"
showing 10 items of 3147 documents
Synthesis and Spectroscopic Characterisation ofbis-Complexes of Cobalt(II), Nickel(II) and Copper(II) with N,N,N′N′-Tetraethylpyridinecarboxamide
1994
Abstract Bis-complexes of Co(II), Ni(II) and Cu(II) with tedpa (N,N,N′N′-tetraethyl-pyridinedicarboxamide) having the general formula [M(tedpa)2]X2 (X = ClO4, PF6) have been synthesized and characterised by i.r., electronic and e.p.r. spectra. The spectroscopic results suggest that the tedpa acts in these compounds as tridentate ligand through two oxygen atoms and a nitrogen (from the pyridine ring) atom. A distorted octahedral environment (MN2O4 chromophores) for the metal atoms is inferred from the spectroscopic data.
Metal complexes of sulfanilamide derivatives. Spectroscopic characterization of the dichloro disulfathiazole methanol copper(II) complex
1993
The synthesis and spectral characterization of the [Cu(Hstz)2(MeOH)Cl2] complex are described. Both polycrystalline powder EPR and single crystal EPR spectra recorded at room temperature show rhombic distortion with values of g1=2.25, g2=2.09 and g3=2.03 in agreement with a copper polyhedron, intermediate between trigonal bipyramid and square pyramidal.
Synthesis, Structure, and Magnetic Properties of Regular Alternating μ-bpm/di-μ-X Copper(II) Chains (bpm = 2,2′-bipyrimidine; X = OH, F)
2012
The preparation and X-ray crystal structure of four 2,2'-bipyrimidine (bpm)-containing copper(II) complexes of formula {[Cu(2)(μ-bpm)(H(2)O)(4)(μ-OH)(2)][Mn(H(2)O)(6)](SO(4))(2)}(n) (1), {[Cu(2)(μ-bpm)(H(2)O)(4)(μ-OH)(2)]SiF(6)}(n) (2), {Cu(2)(μ-bpm)(H(2)O)(2)(μ-F)(2)F(2)}(n) (3), and [Cu(bpm)(H(2)O)(2)F(NO(3))][Cu(bpm)(H(2)O)(3)F]NO(3)·2H(2)O (4) are reported. The structures of 1-3 consist of chains of copper(II) ions with regular alternation of bis-bidentate bpm and di-μ-hydroxo (1 and 2) or di-μ-fluoro (3) groups, the electroneutrality being achieved by either hexaaqua manganese(II) cations plus uncoordinated sulfate anions (1), uncoordinated hexafluorosilicate anions (2), or terminally …
Selective encapsulation of a chloride anion in a 1H-pyrazole Cu2+ metallocage
2021
A self-assembled metallobox from copper(ii) and two macrocycles containing 1H-pyrazole ligands has been prepared. The internal cavity of the box is able to selectively encapsulate a single chloride anion over any other halide anion.
Study of the Interaction Mechanism in the Biosorption of Copper(II) Ions onto Posidonia oceanica and Peat
2012
A systematic approach was used to characterize the biosorption of copper(II) onto two biosorbents, Posidonia oceanica and peat, focusing on the interaction mechanisms, the copper(II) sorption–desorption process and the thermal behavior of the biosorbents. Sorption isotherms at pH 4–6 were obtained and the experimental data were fitted to the Langmuir model with a maximum uptake ( q max ) at pH 6 of 85.78 and 49.69mgg -1 , for P. oceanica and peat, respectively. A sequential desorption (SD) with water, Ca(NO 3 ) 2 , and EDTA was applied to copper-saturated biosorbents. Around 65–70% copper(II) were desorbed with EDTA, indicating that this heavy metal was strongly bound. The reversibility of …
Mass spectrometric investigations of the kinetic stability of chromium and copper complexes with humic substances by isotope-labelling experiments
1999
Isotope-labelling exchange experiments were carried out to investigate the kinetic stability of Cr(III) complexes with humic substances (HS). To compare the results with those of an ion, not expected to form kinetically stable HS complexes with respect to its electron configuration, Cu(II) was investigated under the same conditions. HS solutions of different origin were therefore spiked with 53Cr(III) or 65Cu(II) after saturation of HS with chromium and copper of natural isotopic composition. In fractions of metal/HS complexes with different molecular weight, obtained by ultrafiltration and HPLC/ICP-MS using size exclusion chromatography (SEC), respectively, the isotope ratios of chromium a…
Assessment of the influence of counter ions on biosorption of copper cations in brewer's spent grain - Waste product generated during beer brewing pr…
2019
Abstract The influence that conditioning leached ground barley grain (known as “brewer's spent grain” (BSG)) has on the effectiveness of copper cation sorption was analysed. Saturation with counter ions of functional groups present on the grain surface was carried out in hydrochloric acid, sodium hydroxide, sodium and calcium chloride solutions. For comparison, BSG was also conditioned in demineralised water. Spent barley grain is a by-product of the brewing industry which can be used as a biosorbent in the removal of heavy metals from waste water. Emphasis is placed on the effect of competitive sorption of copper and hydrogen cations and the negative influence of a solution alkalinisation …
Isomerism of [64Cu-NOTA-Bn]-labeled radiotracers: separation of two complex isomers and determination of their interconversion energy barrier using i…
2011
The model complex [(64)Cu((S)-p-NH(2)-Bn-NOTA)](-) ([(64)Cu]1) was used to study the isomerism of [(64)Cu-NOTA-Bn]-labeled radiotracers. Two complex isomers [(64)Cu]1a and [(64)Cu]1b, which were formed at a ratio of 1:9 during the complexation of [(64)Cu]Cu(2+) with (S)-p-NH(2)-Bn-NOTA, were separated using ion pair chromatography. To study the interconversion, the nonradioactive complex isomers Cu1a and Cu1b were separated and thermally treated at 90 °C in both ammonium acetate solution and deionized water. A faster interconversion rate was observed for both isomers with lower concentrations of ammonium ions. At the end of reaction, the thermodynamic Cu1a to Cu1b equilibrium ratio was 6:94…
Dynamics of closure of zinc bis-porphyrin molecular tweezers with copper(II) ions and electron transfer.
2011
Zinc bis-porphyrin molecular tweezers composed of a N(4) spacer bound through pyridyl units to the meso position of porphyrins were synthesized, and the tweezers are closed by the coordination of a copper(II) ion inside the spacer ligand. The effect of the π-π interaction between the porphyrin rings in the closed conformation on the absorption spectra of multi-electron oxidized species and the reduction potentials were clarified by chemical and electrochemical oxidation of the closed form of the zinc bis-porphyrin molecular tweezers in comparison with the open form without copper(II) ion and the corresponding porphyrin monomer. The shifts in redox potentials and absorption spectrum of the p…
Luminescent Ionic Transition-Metal Complexes for Light-Emitting Electrochemical Cells
2012
Higher efficiency in the end-use of energy requires substantial progress in lighting concepts. All the technologies under development are based on solid-state electroluminescent materials and belong to the general area of solid-state lighting (SSL). The two main technologies being developed in SSL are light-emitting diodes (LEDs) and organic light-emitting diodes (OLEDs), but in recent years, light-emitting electrochemical cells (LECs) have emerged as an alternative option. The luminescent materials in LECs are either luminescent polymers together with ionic salts or ionic species, such as ionic transition-metal complexes (iTMCs). Cyclometalated complexes of Ir(III) are by far the most util…