Search results for "Ferro"
showing 10 items of 2451 documents
Self-assembly mechanism of nanoparticles of Ni-based Prussian Blue analogues at the air/liquid interface: a synchrotron X-ray reflectivity study.
2015
Prussian Blue analogue (PBA) nanoparticles can be self-assembled at air/liquid interfaces to build novel materials with interesting magnetic features. Herein, we study the influence of the size of PBA Cs0.4 Ni[Cr(CN)6 ]0.9 and K0.25 Ni[Fe(CN)6 ]0.75 nanoparticles on the self-assembly behavior by synchrotron X-ray reflectivity. Both nanoparticles show similar Z-potential values. The phospholipid dipalmitoylphosphatidylcholine and the amino surfactant dimethyldioctadecylammonium have been used as Langmuir monolayers to anchor the PBA nanoparticles and study the interplay of forces directing the self-assembly of the nanoparticles at the surfactant/liquid interface. Whereas Cs0.4 Ni[Cr(CN)6 ]0.…
Ba and Ni speciation in a nodule of binary Mn oxide phase composition from Lake Baikal
2007
The partitioning and incorporation mechanism of Ni and Ba in a ferromanganese nodule from Lake Baikal were characterized by X-ray microfluorescence, microdiffraction, and absorption spectroscopy. Fe is speciated as goethite, and Mn as romanechite (psilomelane) and 10 A ˚ -vernadite (turbostratic buserite) with minor 7 A ˚ -vernadite (turbostratic birnessite). Barium is associated with romanechite and Ni with vernadite in distinct and irregularly distributed layers, and each type of Mn oxide is separated from the other type by goethite. The binary Mn oxide banding pattern is interpreted by a two-mode accretionary model, in which the variation in Ba flux induced by hydrothermal water pulses d…
On the Use of Metal Purine Derivatives (M=Ir, Rh) for the Selective Labeling of Nucleosides and Nucleotides
2014
The reactions of neutral or cationic IrIII and RhIII derivatives of phenyl purine nucleobases with unsymmetrical alkynes produce new metallacycles in a predictable manner, which allows for the incorporation of either photoactive (anthracene or pyrene) or electroactive (ferrocene) labels in the nucleotide or nucleoside moiety. The reported methodology (metalation of the purine derivative and subsequent marker insertion) could be used for the postfunctionalization and unambiguous labeling of oligonucleotides.
Crystal engineering of 3-D coordination polymers by pillaring ferromagnetic copper(ii)-methylmalonate layers
2007
Three new copper(II) complexes of formula [Cu(Memal)(H2O)]n (1), [Cu2(pyz)(Memal)2] (2) and [Cu2(4,4′-bpy)(Memal)2(H2O)2] (3) (Memal = methylmalonate, pyz = pyrazine and 4,4′-bpy = 4,4′-bipyridine) were obtained and structurally characterized by X-ray diffraction. Complex 1 is a square grid of aquacopper(II) units which are linked by carboxylate-methylmalonate groups in the anti–syn (equatorial–equatorial) coordination mode. The crystal structures of 2 and 3 consist of corrugated layers of copper(II) (2) and aquacopper(II) (3) units with intralayer carboxylate-methylmalonate bridges in the anti–syn (equatorial–apical) coordination mode which are linked through pyrazine (2) and 4,4′-bipyridi…
High-dimensional malonate-based materials: Synthesis, crystal structures and magnetic properties of [M2(mal)2(L)(H2O)2]n·n(H2O) M = Zn(ii), Co(ii); H…
2003
Four novel coordination polymers [M2(mal)2(pym)(H2O)]n·nH2O, M = Zn (1), Co (2) and [M2(mal)2(pyz)(H2O)]n·nH2O, M = Zn (3), Co (4) (H2mal = malonic acid, pym = pyrimidine, pyz = pyrazine), have been synthesized. Compounds 1 and 2 are isomorphous, as are compounds 3 and 4. X-ray diffraction experiments reveal that 1–4 exhibit an interesting 3D-network, containing malonate and either pyrimidine (1 and 2) and pyrazine (3 and 4) as organic ligands. Variable-temperature magnetic susceptibility measurements indicate the occurrence of weak antiferromagnetic interactions between Co(II) ions in 2 and 4.
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
Efficient conversion of orbital Hall current to spin current for spin-orbit torque switching
2021
Spin Hall effect, an electric generation of spin current, allows for efficient control of magnetization. Recent theory revealed that orbital Hall effect creates orbital current, which can be much larger than spin Hall-induced spin current. However, orbital current cannot directly exert a torque on a ferromagnet, requiring a conversion process from orbital current to spin current. Here, we report two effective methods of the conversion through spin-orbit coupling engineering, which allows us to unambiguously demonstrate orbital-current-induced spin torque, or orbital Hall torque. We find that orbital Hall torque is greatly enhanced by introducing either a rare-earth ferromagnet Gd or a Pt in…
Field-induced ferromagnetism due to magneto-striction in 1-D helical chains
2016
Two homochiral copper(II) helices, [Cu(μ1,3-N3)(L1)]n (1) and [Cu(μ1,3-NCO)(L2)]n (2), with end-to-end pseudohalide bridges, were synthesized using two N2O donor achiral Schiff bases via spontaneous chiral resolution. Field-induced ferromagnetic ordering due to magneto-striction in homochiral 1-D helix [Cu(μ1,3-N3)(L1)]n (1) is reported for the first time. At temperatures below 5.5 K, under a magnetic field of 1 T, orthogonality between the magnetic orbitals of copper centres increases significantly due to the contraction of lattice parameters, giving rise to long-range ferromagnetic ordering in the helical chain. The magneto-dielectric results are also indicative of the observed magneto-st…
Estimation of individual Gibbs energies of cation transfer employing the insertion electrochemistry of solid Prussian blue
2011
Abstract A novel method to determine the Gibbs energy of cation transfer between two miscible solvents is described. This method uses electrochemical data for the reversible cation-assisted solid-state reduction of Prussian blue using ferrocene as internal potential standard. Voltammetric data can be used for a direct measurement of the Gibbs energy of ion transfer from one solvent to another using midpeak potentials in solutions of suitable salts in each one of the solvents separately or mixtures of the solvents. Excess Gibbs energies of solvation in solvent mixtures can also be directly estimated. Gibbs energies of cation transfer of Li+, Na+ and K+ ions from water to MeOH, MeCN and DMSO …
Crystal structure of 1-ferrocenyl-2-(4-methyl-benzo-yl)spiro-[11H-pyrrolidizine-3,11'-indeno[1,2-b]quinoxaline].
2014
In the title compound the four-fused-rings system is approximately planar and the pyrrolidine rings of the pyrrolidizine fragment adopt a twist conformation. In the crystal, molecules are linked by C—H⋯O hydrogen bonds and C—H⋯π interactions, forming double-chains parallel to the c axis.