Search results for " Copper"

Metal coordination of azurin in the unfolded state.

1998

Abstract1H NMR data applied to the paramagnetic cobalt(II) derivative of azurin from Pseudomonas aeruginosa have made it possible to show that the metal ion is bound to the protein in the unfolded state. The relaxation data as well as the low magnetic anisotropy of the metal ion indicate that the cobalt ion is tetrahedral in the unfolded form. The cobalt ligands have been identified as the residues Gly45, His46, Cys112 and His117. Met121 is not coordinated in the unfolded state. In this state, the metal ion is not constrained to adopt a bipyramidal geometry, as imposed by the protein when it is folded. This is clear confirmation of the rack-induced bonding mechanism previously proposed for …

Metamagnetism in hydrophobically induced carboxylate (phenylmalonate)-bridged copper(II) layers

2006

Self-assembly of copper(II) ions, phenylmalonate and pyrimidine yields the layered compound [Cu(pym)(Phmal)]n ( 1) where intralayer ferro- and interlayer antiferromagnetic interactions occur with three-dimensional antiferromagnetic ordering at Tc = 2.15 K Lloret Pastor, Francisco, Francisco.Lloret@uv.es ; Julve Olcina, Miguel, Miguel.Julve@uv.es

Bis(4-methylthio)phenylthiomethane as assembling ligand for the construction of Cu(I) and Hg(II) coordination polymers. Crystal structures and topolo…

2016

International audience; The novel 1D coordination polymer (CP) [{Cu(mu(2)-Br)(2)Cu}(mu-L2)(2)] CP2 has been obtained by reaction of the tetrakisthioether p-MeSC6H4SCH2SC6H4SMe-p (L2) with CuBr in a 1: 2 metal-to ligand ratio. In contrast to the previously described CP [{Cu(mu(2)-Br)(2)Cu}(mu-L1)(2)] CP1 obtained by reaction of the tetrakisthioether p-MeOC6H4SCH2SC6H4OMe-p (L1) with CuBr, the two independent extended 1D ribbons contain bent Cu(mu(2)-Br)(2)Cu units of the butterfly-type with short Cu center dot center dot center dot Cu separations of 2.679(1) and 2.613(1) angstrom. In contrast to the common planar rhomboid Cu(mu(2)-Br)(2)Cu cluster, this butterfly-shaped geometry of the core …

CuCl catalyzed radical cyclisation of N-alpha-perchloroacyl-ketene-N,S-acetals: a new way to prepare disubstituted maleic anhydrides

2012

The discovery that cycloalkanes can form thermomorphic systems with typical polar organic solvents has led to the development of less-polar electrolyte solutions. Their mixing and separation can be regulated reversibly at a moderate temperature range. The phase switching temperature can be controlled by changing the solvent compositions. While biphasic conditions are maintained below the phase switching temperature, conductive monophasic conditions as less-polar electrolyte solutions are obtained above the phase switching temperature. After the electrochemical transformations, biphasic conditions are reconstructed below the phase switching temperature, facilitating the separation of cycloal…

Study of immunotoxicity responses of Sabella spallanzanii exposed to copper sulphate

2022

Selective G-quadruplex stabilizers: Schiff-base metal complexes with anticancer activity

2014

The affinity of three square-planar nickel(II) (1), copper(II) (2) and zinc(II) (3) Schiff-base complexes for wild-type human telomeric (h-Telo) and protooncogene c-myc G-quadruplex (G4) DNA was investigated by UV-visible absorption spectroscopy and circular dichroism. DNA-binding constants (Kb) were determined by spectrophotometric titrations for both G4-DNA and B-DNA. The results obtained point out that the three metal complexes selectively bind G4-DNA with higher affinity, up to two orders of magnitude, with respect to B-DNA. The nickel(II) complex 1 was found to be the most effective G4-DNA stabilizer and the Kb values decrease in the order 1 > 2 ≈ 3. Innovative computational investigat…

Effectiveness of clays and copper products in the control of Bactrocera oleae (Gmelin)and Ceratitis capitata (Wiedemann) in organic farming

2008

Tests on the effect of clays (kaolin and bentonite) and copper products (hydroxide and oxychloride) in the control of olive fruit fly, Bactrocera oleae (Gmelin), and Mediterranean fruit fly, Ceratitis capitata (Wiedemann), were carried out from 2003 to 2006 in olive groves, and in 2005 and 2006 in organic orange orchards (early ripening cv. Navelina). Results demonstrate an efficacy of kaolin products in reducing attacks of Bactrocera oleae to olives and those of Ceratitis capitata to oranges. In olive groves, they gave similar or better results than copper hydroxide. Bentonite AG/W8 showed a significant reduction in punctures towards C. capitata. Bentonite products and BPLK kaolin are clea…

Control of Bactrocera oleae by low environmental impact methods: NPC methodology to evaluate the efficacy of lure-and-kill method and copper hydroxid…

2011

The NonParametric Combination (NPC) methodology is proposed to verify the influence of the lure-and-kill method, using Ecotraps (Vioryl SA), on the distribution of Bactrocera oleae (Rossi) (Diptera Tephritidae) infestation in olive groves, and the integration of this method with copper hydroxide sprayings. This approach does not require the verification of any rigid assumption as many parametric methods do. Results of field trials indicate a strict relationship among the efficiency of the lure-and-kill method on time, dimension of the field, and population density of the olive fly. Moreover, the lure-and-kill method alone seems insufficient to provide an efficient control of the olive fly p…

Effectiveness of mass trapping by bottle traps baited with salt sardines to control Bactrocera oleae (Gmelin)

2007

Various substances are known as attractants of tephritid flies; the putrescine and other compounds coming from animal decay have been positively tested for attraction of Bactrocera cucurbitae (Coquillett) and other tephritids. In Sicilian coastal areas, usually heavily infested by Bactrocera oleae (Gmelin), few organic farmers producing high quality olive oil apply mass trapping by using bottle traps baited with salt sardines. The aim of this paper is to test the effectiveness of this kind of mass trapping to control the olive fruit fly. In 2005 and 2006 mass trapping was tested in an organic olive grove (Cerasuola cultivar) located in Trapani. In 2005 two plots were delineated: 189 untreat…

On the G‐quadruplex binding of a new class of Ni(II), Cu(II) and Zn(II) salphen‐like complexes

2021

The involvement of non-canonical DNA structures, such as Gquadruplex (G4) DNA, in cancer development and progression has set the pace towards the renaissance of DNA-binding metal complexes. In this work, we report the DNA-binding of three Ni(II), Cu(II), Zn(II) complexes of a salphen-like N4-donor ligand, bearing two imidazole groups condensed with a phenylenediamine moiety. Both duplex and G4 DNAs derived from human telomeres (hTelo), and a sequence mimicking the promoter of the oncogene myc (c-myc) were studied. UV-Vis and circular dichroism spectroscopic binding studies pointed out that, while all the three complexes bind the selected oligonucleotides, the Cu(II) derivative is the strong…