Search results for "COPP"
showing 10 items of 3147 documents
A counterion study of a series of [Cu(P^P)(N^N)][A] compounds with bis(phosphane) and 6-methyl and 6,6′-dimethyl-substituted 2,2′-bipyridine ligands …
2021
The syntheses and characterisations of a series of heteroleptic copper(i) compounds [Cu(POP)(Mebpy)][A], [Cu(POP)(Me2bpy)][A], [Cu(xantphos)(Mebpy)][A] and [Cu(xantphos)(Me2bpy)][A] in which [A]− is [BF4]−, [PF6]−, [BPh4]− and [BArF4]− (Mebpy = 6-methyl-2,2′-bipyridine, Me2bpy = 6,6′-dimethyl-2,2′-bipyridine, POP = oxydi(2,1-phenylene)bis(diphenylphosphane), xantphos = (9,9-dimethyl-9H-xanthene-4,5-diyl)bis(diphenylphosphane), [BArF4]− = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate) are reported. Nine of the compounds have been characterised by single crystal X-ray crystallography, and the consequences of the different anions on the packing interactions in the solid state are discussed. T…
Copper Proteins with Dinuclear Active SitesBased in part on the article Copper Proteins with Dinuclear Active Sites by Konrad Lerch which appeared in…
2006
Copper proteins with dinuclear active sites comprise proteins with different structures and functions. The phenoloxidase, tyrosinase, and catecholoxidase are responsible for browning by starting the synthesis of melanin. These enzymes are involved in the primary immune response in invertebrates, plants, fungi as well as in the sclerotization of arthropods. The respiratory proteins hemocyanins are responsible for oxygen transport in some arthropods and molluscs. However, they can be converted to enzymes exhibiting phenoloxidase activity. Based on X-ray structures of hemocyanins and a catecholoxidase, large parts of folding motifs are very similar although the sequence identities are far belo…
Structural and functional models for the dinuclear copper active site in catechol oxidases
2003
Two new mu-methoxo-bridged dinuclear copper(II) complexes with a N-substituted sulfonamide, [Cu(mu-OMe)(L)(NH(3))](2) (1) and [Cu(mu-OMe)(L)(DMSO)](2) (2) [HL, N-2-(4-methylbenzothiazole)benzenesulfonamide], have been prepared and characterized by single-crystal X-ray difraction analyses. Compound 1 crystallizes in the monoclinic space group C(2)/c with a=22.0678(18), b=7.9134(7), c=21.1186(18)A, beta=113.788(4) degrees and Z=8. Compound 2 crystallizes in the monoclinic space group C(2)/c with a=18.0900(10), b=9.5720(10), c=24.2620(10) A, beta=98.7120(10) degrees and Z=8. In both complexes the copper atoms have square-planar environments bridged by two oxygen atoms from methoxide groups. Ma…
Exopolysaccharides favor the survival of Erwinia amylovora under copper stress through different strategies.
2010
Erwinia amylovora causes fire blight, a destructive disease of rosaceous plants very difficult to control. We demonstrated that copper, employed to control plant diseases, induces the "viable-but-nonculturable" (VBNC) state in E. amylovora. Moreover, it was previously reported that copper increases production of its main exopolysaccharide (EPS), amylovoran. In this work, the copper-complexing ability of amylovoran and levan, other major EPS of E. amylovora, was demonstrated. Following this, EPS-deficient mutants were used to determine the role of these EPSs in survival of this bacterium in AB mineral medium with copper, compared to their wild type strain and AB without copper. Tot…
A New Layered Compound Containing [PMo12O40]3- and Both 5- and 6-Coordinated Homoleptic (1-(2-Chloroethyl)tetrazole)Copper(II) Cations
2002
The synthesis, crystal structure and physical properties of the complex obtained from the reaction between the polyoxometalate anion [PMo12O40]3- copper(II) and the ligand 1-(2-chloroethyl)tetrazole (teec) are described. This compound has been synthesized as a model for designing materials containing both magnetic polyoxometalate anions and iron(II) spin-crossover cations. Keywords. Coordination chemistry; Heterocycles; Polyoxometalates; Structure elucidation; Tetrazole.
Darstellung und eigenschaften von formazanen aus polyacroleinen. Polymere acroleine, 17. Mitt.1
1960
Die Herstellung von verschiedenen, substituierten Polyacroleinphenylhydrazonen wird beschrieben. Durch Umsetzung mit Diazoniumsalzen entstehen Polymere mit Formazan-Gruppen. Diese lassen sich zu Tetrazolium-Gruppen dehydrieren. Die polymeren Formazane bilden bei geeigneten Substituenten mit Kupfer-und Uranyl-Ionen Komplexe und konnen daher als selektive Ionenaustauscher verwendet werden. Ferner werden einige polymere Azomethine beschrieben. The preparation of various substituted polyacroleinphenylhydrazones is reported. Polymers with formazane groups are obtained by the reaction of diazonium salts, which can be dehydrogenized to tetrazolium-groups. With suitable substitutes, the polymerie f…
Spectroscopic behaviour of metal–drug complexes. Infrared spectra of Cu(II) complexes with 5-amino-1,3,4-thiadiazole-2-thiol (Hatm)
1997
Abstract The infrared spectra of the drug Hatm and its copper (II) complexes with stoichiometry [Cu(atm) 2 (H 2 O)] and [Cu(Hatm)(HIm) 2 (SO 4 )] are reported and discussed. The Raman spectrum of Hatm is also reported. An assignment of Hatm, HIm, H 2 O and SO 4 modes in the complexes is proposed in comparison with the modes of the free ligands. Important information about the metal–ligand vibrations has been obtained.
ChemInform Abstract: Highly Enantioselective Copper(I)-Catalyzed Conjugate Addition of 1,3-Diynes to α,β-Unsaturated Trifluoromethyl Ketones.
2015
The conjugate diynylation of α,β-saturated trifluoromethyl ketones is carried out at low catalytic loading (2.5 mol% for aryl substituents) of a copper(I)—MeO-BIPHEP complex, triethylamine and a terminal 1,3-diyne.
Electrochemistry, spectroelectrochemistry and catalytic activity of biscobalt bisporphyrin dyads towards dioxygen reduction
2011
Three face-to-face biscobalt bisporphyrin dyads, including one incorporating a copper(II) ion inside the linker, were synthesized and characterized both spectroscopically and electrochemically in three non-aqueous solvents, dichloromethane, benzonitrile and pyridine. The electrocatalytic reduction of dioxygen with these derivatives on an electrode surface in 1.0 M HClO4 was also investigated and the results are compared to that obtained with "regular" Pacman biscobalt bisporphyrins under the same experimental conditions. Surprisingly, the tris-metal species ( Cu-bisCo ) catalyzes the reduction of O2 mainly via a 2e- transfer process, leading to H2O2 , while the bis-metal (bisCo) catalyst p…
ChemInform Abstract: One-Pot Synthesis of Pyrrole-2-carboxylates and -carboxamides via an Electrocyclization/Oxidation Sequence.
2015
An electrocyclic ring closure is the key step of an efficient one-pot method for the synthesis of pyrrole-2-carboxylates and -carboxamides from chalcones and glycine esters or amides. The 3,4-dihydro-2H-pyrrole intermediates generated in situ are oxidized to the corresponding pyrroles by stoichiometric oxidants or by catalytic copper(II) and air in moderate to high yields. A wide range of functional groups are tolerated, and further combination with an in situ bromination gives access to polyfunctional pyrrole scaffolds.