Search results for "spin [structure function]"
showing 10 items of 1132 documents
Regularized pseudopotential for mean-field calculations
2019
We present preliminary results obtained with a finite-range two-body pseudopotential complemented with zero-range spin-orbit and density-dependent terms. After discussing the penalty function used to adjust parameters, we discuss predictions for binding energies of spherical nuclei calculated at the mean-field level, and we compare them with those obtained using the standard Gogny D1S finite-range effective interaction.
Guest Induced Strong Cooperative One- and Two-Step Spin Transitions in Highly Porous Iron(II) Hofmann-Type Metal-Organic Frameworks.
2017
[EN] The synthesis, crystal structure, magnetic, calorimetric, and Mo¿ ssbauer studies of a series of new Hofmann-type spin crossover (SCO) metal¿organic frameworks (MOFs) is reported. The new SCO-MOFs arise from self-assembly of FeII, bis(4-pyridyl)butadiyne (bpb), and [Ag(CN)2] ¿ or [MII(CN)4] 2¿ (MII = Ni, Pd). Interpenetration of four identical 3D networks with ¿-Po topology are obtained for {Fe(bpb)[AgI (CN)2]2} due to the length of the rod-like bismonodentate bpb and [Ag(CN)2] ¿ ligands. The four networks are tightly packed and organized in two subsets orthogonally interpenetrated, while the networks in each subset display parallel interpenetration. This nonporous material undergoes a…
Synthesis and characterization of a new layered organic-inorganic hybrid nickel(II) 1,4 : 5,8-naphthalenediimide bis-phosphonate, exhibiting canted a…
2008
A new Ni(II) layered hybrid organic-inorganic compound of formula Ni{sub 2}[(NDI-BP)(H{sub 2}O){sub 2}].2H{sub 2}O has been prepared in very mild conditions from N,N'-bis(2-phosphonoethyl)napthalene-1,4:5,8-tetracarboximide (NDI-BP ligand) and NiCl{sub 2}. The X-ray powder structure characterization of the title compound suggests a pillared layered organic-inorganic hybrid structure. The distance between the organic and inorganic layers has been found to be 17.8 A. The inorganic layers consist of corner sharing [NiO{sub 5}(H{sub 2}O)] octahedra and they are pillared by the diphosphonate groups. DC and AC magnetic measurements as a function of temperature and field indicate the presence of 2…
A reversible hydrogen‐bond isomerization triggered by an abrupt spin crossover near room temperature.
2020
The spin crossover salt [Fe(bpp) 2 ](isonicNO) 2 ·2.4H 2 O ( 1 ·2.4H 2 O) (bpp = 2,6‐bis(pyrazol‐3‐yl)pyridine; isonicNO = isonicotinate N‐oxide anion) exhibits a very abrupt spin crossover at T 1 /2 = 274.4 K. This triggers a supramolecular linkage (H‐bond) isomerization that responds reversibly towards light irradiation or temperature change. Isotopic effects in the thermomagnetic behaviour reveal the importance of hydrogen bonds in defining the magnetic state. Further, the title compound can be reversibly dehydrated to afford 1 , a material that also exhibits spin crossover coupled to H‐bond isomerization, leading to strong kinetic effects in the thermomagnetic properties.
Influence of Host-Guest and Host-Host Interactions on the Spin-Crossover 3D Hofmann-type Clathrates {FeII(pina)[MI(CN)2]2·xMeOH (MI = Ag, Au)
2019
[EN] The synthesis, structural characterization and magnetic properties of two new isostructural porous 3D compounds with the general formula {FeII(pina)[MI(CN)2]2}·xMeOH (x = 0¿5; pina = N-(pyridin-4-yl)isonicotinamide; MI = AgI and x ~ 5 (1·xMeOH); MI = AuI and x ~ 5 (2·xMeOH)) are presented. The single-crystal X-ray diffraction analyses have revealed that the structure of 1·xMeOH (or 2·xMeOH) presents two equivalent doubly interpenetrated 3D frameworks stabilized by both argentophilic (or aurophilic) interactions and interligand C¿O···HC H-bonds. Despite the interpenetration of the networks, these compounds display accessible void volume capable of hosting up to five molecules of methano…
Hexachlororhenate(IV) salts of ruthenium(III) cations: X-ray structure and magnetic properties
2012
Abstract Two novel rhenium(IV)–ruthenium(III) compounds of formulae [RuCl(NH3)5]2[ReCl6]Cl2 (1) and [RuCl2(en)2]2[ReCl6]·2CH3CN (2) (en = 1,2-ethylenediamine) have been prepared and characterized. Their crystal structures were determined by single-crystal X-ray diffraction. 1 crystallizes in the monoclinic system with C2/m as space group, whereas 2 crystallizes in the triclinic system with space group P(−1). The crystal structures of 1 and 2 are made up of discrete [ReCl6]2− anions and [RuCl(NH3)5]2+ (1) or [RuCl2(en)2]+ (2) cations held together by N–H···Cl hydrogen bonds, van der Waals and electrostatic forces. The magnetic properties were investigated from susceptibility measurements per…
Assembly and encapsulation of coordination tectons driven by hydrogen-bondingand space-filling
2001
[FR] Le composé ¿Fe(LI)3¿2¿Fe(H2O)6¿(ClO4)6 (2), LI = 1,10-phénanthroline-5,6-dione, a été synthétisé et caractérisé. La structure cristalline 2 est définie par un assemblage bidimensionnel non covalent, peu commun, constitué par des tectons chiraux ¿Fe(LI)3¿2+, assemblés par des cations ¿Fe(H2O)6¿2+ encapsulés dans des cages. Ces cages sont formées par 12 liaisons hydrogène établies entre les molécules d¿eau coordinées et les groupes dione appartenant à six molecules chirales ¿Fe(LI)3¿2+ ¿, ¿ alternées.
Singlet‐Contrast Magnetic Resonance Imaging: Unlocking Hyperpolarization with Metabolism
2020
Abstract Hyperpolarization‐enhanced magnetic resonance imaging can be used to study biomolecular processes in the body, but typically requires nuclei such as 13C, 15N, or 129Xe due to their long spin‐polarization lifetimes and the absence of a proton‐background signal from water and fat in the images. Here we present a novel type of 1H imaging, in which hyperpolarized spin order is locked in a nonmagnetic long‐lived correlated (singlet) state, and is only liberated for imaging by a specific biochemical reaction. In this work we produce hyperpolarized fumarate via chemical reaction of a precursor molecule with para‐enriched hydrogen gas, and the proton singlet order in fumarate is released a…