Search results for "Bimetal"
showing 10 items of 191 documents
A molecular chemical approach to the magnetic multilayers
1999
Abstract Using the bi-dimensional bimetallic networks based upon oxalate complexes, it is possible to prepare new multilayered materials by insertion of ‘electroactive’ molecules in between these layers. According to this approach a new family of compounds presenting alternating ferromagnetic—paramagnetic layers have been successfully prepared. Here we present the magnetic and specific heat characterization.
Design of single cyanide-bridged tetranuclear bimetallic rectangles exhibiting ferromagnetic coupling
2005
Abstract The cyanide-bridged tetranuclear bimetallic rectangles ( XPh 4 ) 4 [ Fe 2 III Cu 2 II ( μ - CN ) 4 ( CN ) 8 ( L ) 2 ] · n H 2 O [X = P (1) and As (2); L = bpcam (1) and bpca (2); n = 4 (1) and 0 (2)] have been prepared and their crystal structures were characterized by single crystal X-ray diffraction; 1 exhibits intramolecular ferromagnetic interactions (J1 = +3.7 cm−1 and J2 = +7.0 cm−1, H = - J 1 [ S Fe ( 1 ) · S Cu ( 1 ) + S Fe ( 1 a ) · S Cu ( 1 a ) ] − J 2 [ S Fe ( 1 ) · S Cu ( 1 a ) + S Fe ( 1 a ) · S Cu ( 1 ) ] + D [ S Fe ( 1 ) z 2 + S Fe ( 1 a ) z 2 ] ) leading to a low-lying S = 2 spin state.
Unraveling the Formation of Core−Shell Structures in Nanoparticles by S-XPS
2010
The combination of the surface sensitivity of X-ray photoelectron spectroscopy (XPS) with the high flux and variable photon energy excitation of Synchrotron radiation (S-XPS) is used to probe the atomic distribution of bimetallic nanoparticles. Based on the energy dependence of the photoemission differential cross section of core level photoelectrons, we propose a methodology to monitor the formation and to evaluate sizes of the core−shell structure. We have successfully applied it to unveil the mechanism involved in the atomic rearrangement of thermally treated Pt0.7Pd0.3 nanoparticles.
Intercalation of decamethylferrocenium cations in bimetallic oxalate-bridged two-dimensional magnets
1997
The structure and magnetic properties of novel hybrid molecule-based magnets formed by combination of two magnetically active sublattices, the bimetallic oxalatobridged honeycomb net [MnIIMIII(ox)3] (MII = Mn, Fe, Co, Cr, Ni, Cu; MIII = Cr, Fe) and the organometallic cation decamethylferrocenium, are reported. Clemente Leon, Miguel, Miguel.Clemente@uv.es ; Coronado Miralles, Eugenio, Eugenio.Coronado@uv.es ; Galan Mascaros, Jose Ramon, Jose.R.Galan@uv.es ; Gomez Garcia, Carlos Jose, Carlos.Gomez@uv.es
(Ag)Pd-Fe3O4 Nanocomposites as Novel Catalysts for Methane Partial Oxidation at Low Temperature
2020
Nanostructured composite materials based on noble mono-(Pd) or bi-metallic (Ag/Pd) particles supported on mixed iron oxides (II/III) with bulk magnetite structure (Fe3O4) have been developed in order to assess their potential for heterogeneous catalysis applications in methane partial oxidation. Advancing the direct transformation of methane into value-added chemicals is consensually accepted as the key to ensuring sustainable development in the forthcoming future. On the one hand, nanosized Fe3O4 particles with spherical morphology were synthesized by an aqueous-based reflux method employing different Fe (II)/Fe (III) molar ratios (2 or 4) and reflux temperatures (80, 95 or 110 °
Design of Low-Dimensional Ferrimagnetic Compounds: New Magnetic Lattices in the “EDTA-Family”
1987
The ability of EDTA to wrap around one metal atom (M′) while still providing bridging carboxylate groups to a second atom (M) is the basis for the obtainment of a wide variety of low-dimensional bimetallic ordered systems.
Structural and Magnetic Insights into the Trinuclear Ferrocenophane and Unexpected Hydrido Inverse Crown Products of Alkali‐Metal‐Mediated Manganatio…
2008
With the aim of introducing the diisopropylamide [NiPr(2)](-) ligand to alkali-metal-mediated manganation (AMMMn) chemistry, the temperature-dependent reactions of a 1:1:3 mixture of butylsodium, bis(trimethylsilylmethyl)manganese(II), and diisopropylamine with ferrocene in hexane/toluene have been investigated. Performed at reflux temperature, the reaction affords the surprising, ferrocene-free, hydrido product [Na(2)Mn(2) (mu-H)(2){N(iPr)(2)}(4)]2 toluene (1), the first Mn hydrido inverse crown complex. Repeating the reaction rationally, excluding ferrocene, produces 1 in an isolated crystalline yield of 62 %. At lower temperatures, the same bimetallic amide mixture leads to the manganati…
Cyano-Bridged Bimetallic Assemblies from Hexacyanometalate, [M(CN)6]3- (M = MnIII and FeIII), and [M(N4-macrocycle)]2+ (M = FeIII, NiII and ZnII) Bui…
2001
Reactions between [M(N4-macrocycle)]2+ (M = ZnII and NiII; macrocycle ligands are either CTH = d,l-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane or cyclam = 1,4, 8, 11-tetrazaazaciclotetradecane) and [M(CN)6]3- (M = FeIII and MnIII) give rise to cyano-bridged assemblies with 1D linear chain and 2D honeycomblike structures. The magnetic measurements on the 1D linear chain complex [Fe(cyclam)][Fe(CN)6]·6H2O 1 points out its metamagnetic behavior, where the ferromagnetic interaction operates within the chain and the antiferromagnetic one between chains. The Neel temperature, TN, is 5.5 K and the critical field at 2 K is 1 T. The unexpected ferromagnetic intrachain interaction can…
Insertion of a single-molecule magnet inside a ferromagnetic lattice based on a 3D bimetallic oxalate network: Towards molecular analogues of permane…
2014
The insertion of the single-molecule magnet (SMM) [MnIII(salen) (H2O)]2 2+ (salen2-=N,N-ethylenebis- (salicylideneiminate)) into a ferromagnetic bimetallic oxalate network affords the hybrid compound [MnIII(salen)(H2O)] 2[MnIICrIII(ox)3] 2×(CH3OH)×(CH3CN)2 (1). This cationic Mn2 cluster templates the growth of crystals formed by an unusual achiral 3D oxalate network. The magnetic properties of this hybrid magnet are compared with those of the analogous compounds [Mn III(salen)(H2O)]2[ZnIICr III(ox)3]2×(CH3OH) ×(CH3CN)2 (2) and [InIII(sal 2-trien)][MnIICrIII(ox)3] ×(H2O)0.25×(CH3OH) 0.25×(CH3CN)0.25 (3), which are used as reference compounds. In 2 it has been shown that the magnetic isolatio…
Effects of sequence, connectivity, and counter ions in new amide-linked Ru(tpy)2-Re(bpy) chromophores on redox chemistry and photophysics.
2013
New cationic metallo ligands L1-L3 based on bis(terpyridine) ruthenium(II) complexes decorated with differently substituted 2,2'-bipyridines attached via amide groups (5-NHCO-bpy, 4-CONH-bpy, 5-CONH-bpy) were prepared. Coordination of Re(I)Cl(CO)(3) fragments to the bpy unit gives the corresponding bimetallic Ru~Re complexes 1-3. Hydrogen bonds of the bridging amide groups to [PF(6)](-) counterions or to water molecules are observed both in the solid state and in solution. The impact of the amide orientation, the connecting site, and the coordination of counterions on redox and photophysical properties is explored. Both the metallo ligands L1-L3 and the bimetallic complexes 1-3 are emissive…