Search results for "NICKEL"
showing 10 items of 1087 documents
Copper(II) and nickel(II) chelates with dihydrogen Trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetate(2−) ion (H2CDTA2−). Synthesis, XRD structure a…
1996
Abstract Stoichiometric reactions of metal hydroxycarbonates with the acid trans -1,2-cyclohexanediaminotetraacetic acid (H 4 CDTA) in water under reduced pressure yielded [Cu(H 2 CDTA)]·H 2 O ( I ) and [Ni(H 2 CDTA) (H 2 O)]·4H 2 O ( II ). Both compounds were characterized by TG-DTA analysis, spectral properties (IR, reflectance and RSE) and X-ray diffraction. In I the copper(II) atom exhibits a distorted square-base coordination (type 4+1) by chelation of one H 2 CDTA 2− ligand through two N and two O (carboxylate) at the square base and one O (carboxylic) at the apex of the coordination polyhedron; a second carboxymethyl group of H 2 CDTA 2− remains free. In II the H 2 CDTA 2− chelating …
Insertion of light-harvesting chlorophyll a/b protein into the thylakoid
2000
The major light-harvesting chlorophyll a/b-binding protein (Lhcb1,2) of photosystem II is inserted into the thylakoid via the signal recognition particle dependent pathway. However, the mechanism by which the protein enters the membrane is at this time unknown. In order to define some topographical restrictions for this process, we constructed several recombinant derivatives of Lhcb1 carrying hexahistidine tags at either protein terminus or in the stromal loop domain. Additionally, green fluorescent protein (GFP) was fused to either terminus. None of the modifications significantly impair the pigment-binding properties of the protein in the in vitro reconstitution of LHCII. With the excepti…
New Magnetic Thin Film Hybrid Materials Built by the Incorporation of Octanickel(II)-oxamato Clusters Between Clay Mineral Platelets
2011
We report on a new method based on the combination of Langmuir-Schaefer deposition with self-assembly to insert highly anisotropic Ni(8) molecules in a hybrid organic-inorganic nanostructure. Spectroscopic, crystallographic, and magnetic data prove the successful insertion of the guest cationic molecule between templating clay platelets. These results open a new route toward the highly controlled fabrication of tailored functional organic-inorganic nanomaterials.
1D antiferromagnetism in spin‐alternating bimetallic chains
1990
The magnetic and thermal properties of the ordered bimetallic chain CoNi(EDTA)⋅6H2O in the very low‐temperature range are reported. The magnetic behavior does not exhibit the characteristic features of 1D ferrimagnets, but a continuous decrease of χmT towards zero at absolute zero. This 1D antiferromagnetic behavior results from an accidental compensation between the moments located at the two sublattices. This behavior, as well as the specific‐heat results, are modeled on the basis of an Ising‐exchange model that considers both alternating spins and Landé factors, and a zero‐field splitting on the Ni site. Eugenio.Coronado@uv.es ; Fernando.Sapina@uv.es
The ferrimagnetic compounds CoM[M’(EDTA)]2⋅4H2O(M,M’=Co,Ni): Magnetic characterization of CoCo[Ni(EDTA)2]⋅4H2O
1990
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Paramagnetic Cobalt and Nickel Derivatives of Alcaligenes denitrificans Azurin and Its M121Q Mutant. A 1H NMR Study
1996
Using cobalt or nickel to replace copper in native azurin allows one to fingerprint the metal coordination site of the protein. The metal sites of wild type Alcaligenes denitrificans azurin and its M121Q mutant are clearly distinguishable through the paramagnetic 1H NMR spectra of the Ni(II) and Co(II) derivatives. In the wild type azurin, Gly45 coordinates to nickel or cobalt, while Met121 appears as a weak metal ligand. On the contrary, in the M121Q azurin mutant, the metal exhibits a clear preference for the Gln121, which coordinates through the side chain carbonyl oxygen, and Gly45 is not a ligand. Changes in the isotropic shifts and relaxation properties of signals from the Cys112, His…
Adducts of organolead(IV) and organothallium(III) chlorides with N,N′-ethylenebis(salicylideneiminato)nickel(II) and bis(β-mercaptoethylamine)nickel(…
1974
Abstract Novel 1/1 adducts of organolead(IV) and organothallium(III) chlorides with the complexes N,N′-ethylenebis(salicylideneiminato)nickel(II) and bis(β-mercaptoethylamine)nickel(II) have been synthesized. Their configurations have been investigated in the solid state by IR and electronic spectroscopy and by magnetic measurements.
Complexes of organometallic compounds
1974
Abstract Novel 1/1 adducts have been obtained from the complex N , N ′-ethylenebis(salicylideneiminato)nickel(II) (NiSalen) with di- and mono-organotin(IV) chlorides, and their solid state configuration investigated by Mossbauer , IR and electronic spectroscopy and magnetic measurements. In coordinated NiSalen the square planar structure is maintained around Ni II , and the coordination to tin involves three-coordinate phenolic oxygens. The environment of Sn IV is judged to be octahedral in both types of compounds. A trans -R 2 , cis -Cl 2 configuration is advanced for R 2 SnCl 2 NiSalen.
EPR and Magnetic Susceptibility Studies of Cobalt(II)- and Nickel(II)-Substituted Azurins from Pseudomonas aeruginosa. Electronic Structure of the Ac…
1996
The electronic properties of cobalt(II)- and nickel(II)-substituted azurins from Pseudomonas aeruginosa have been investigated. EPR data for the cobalt derivative and paramagnetic susceptibility data for the nickel derivative are reported. The EPR spectrum of Co(II)−azurin shows the typical pattern of a Kramers' doublet (±1/2) associated with an S = 3/2 ground state in a distorted axial symmetry environment. The temperature dependence of the EPR intensities shows that this Kramers' doublet is the excited doublet and, therefore, that the corresponding zero-field splitting parameter D is negative (∼−3.5 cm-1). The mean g value is equal to 2.3. Nickel(II) azurin exhibits an effective magnetic …
Coordination Complexes of a Neutral 1,2,4-Benzotriazinyl Radical Ligand: Synthesis, Molecular and Electronic Structures, andMagnetic Properties
2015
A series of d-block metal complexes of the recently reported coordinating neutral radical ligand 1-phenyl-3-(pyrid-2-yl)-1,4-dihydro-1,2,4-benzotriazin-4-yl (1) was synthesized. The investigated systems contain the benzotriazinyl radical 1 coordinated to a divalent metal cation, MnII, FeII, CoII, or NiII, with 1,1,1,5,5,5-hexafluoroacetylacetonato (hfac) as the auxiliary ligand of choice. The synthesized complexes were fully characterized by single-crystal X-ray diffraction, magnetic susceptibility measurements, and electronic structure calculations. The complexes [Mn(1)(hfac)2] and [Fe(1)(hfac)2] displayed antiferromagnetic coupling between the unpaired electrons of the ligand and the meta…