Search results for "Magnetization"

( n -Bu 4 N) 2 [Fe(dcbdt) 2 ] 2 . Synthesis, crystal structure and magnetic characterisation

2003

Abstract The ( n -Bu 4 N) 2 [Fe(dcbdt) 2 ] 2 complex, where 4,5-dicyanobenzene-1,2-dithiolate (dcbdt), was prepared and characterised by X-ray diffraction, Mossbauer spectroscopy and magnetisation measurements. The crystal structure as determined by single crystal X-ray diffraction is triclinic, space group P 1 with cell parameters a =9.5660(1) A, b =13.0200(2) A, c =16.0850(2) A, α =67.554°(1), β =86.797°(1), γ =70.523°(1), V =1738.77(4) A 3 and it consists in strongly dimerised [Fe(dcbdt) 2 ] − units, which are stacked side by side as chains along a . The magnetic susceptibility shows that the [Fe(dcbdt) 2 ] − units have a low spin S =1/2 configuration and, besides a strong intradimer ant…

Structural and magnetic studies of mononuclear lanthanide complexes derived from Ν-rich chiral Schiff bases.

2021

Zn(II) complexes containing N, N,N and N,N,N pyridine (dPy) ligands tend to display improved fluorescence efficiencies in comparison with their starting ligands benefiting from the chelation enhanced effect (CHEF) and preventing photoinduced electron transfer (PET) mechanisms by the coordination of their lone pair electrons. Nevertheless, the size of Zn(II) makes steric crowding an important factor to be considered, since it can promote the elongation of the coordination bonds that weakens their strength and favors the reduction of fluorescence efficiencies through PET processes. For that reason, in this contribution we have performed a systematic study of Zn(II) compounds based on α-acetam…

Structural characterization and magnetic property studies of a mixed-valence {CoIIICoII4} complex with a μ4-oxo tetrahedral {CoII4} motif

2020

We have synthesized and structurally characterized a new mixed valence pentanuclear Co complex, bearing a rare μ4-O-tetrahedral CoII4 unit, by employing a pyridine-like Schiff base ligand. We have performed DC magnetic susceptibility and magnetization measurements over polycrystalline samples and chemical quantum computations in order to understand the exchange interaction pattern within Co(II) sites and ground state magnetic anisotropy. This new complex shows an overall antiferromagnetic exchange interaction whose strength strongly depends on the local symmetry of Co(II) sites. Also, local ion magnetic anisotropy reveals a strongly axial behaviour with the lowest Kramers doublet (KD) at ea…

A Novel One-Dimensional Cyano-Bridged Ni3Fe2 Ferromagnet Constructed from Bimetallic Molecular Squares

2003

Reaction of the complex [Ni(rac-CTH)](2+) (rac-CTH = rac-5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) with [Fe(CN)(6)](3-) leads to a novel cyano-bridged Ni(3)Fe(2) complex, [[Ni(rac-CTH)](3)[Fe(CN)(6)](2)](4). The structure consists of an alternating arrangement of [Fe(CN)(6)Ni(rac-CTH)](2) squares and trans-planar [Ni(rac-CTH)](2+) units bridged by cyanide groups to give a neutral 1D chain running along the a axis. Magnetic measurements reveal the occurrence of ferromagnetic coupling between Fe(III) and Ni(II) ions and 3D magnetic ordering at 3 K due to interchain interactions. Canting of the moments is inferred from the low value of the magnetization of the saturation bel…

Modulating magnetic dynamics through tailoring the terminal ligands in Dy2 single-molecule magnets

2020

Complexation of dysprosium(III) ions with a multidentate hydrazone ligand, N-[(E)-pyridin-2-ylmethylideneamino]pyridine-2-carboxamide (L), in the presence of different β-diketonate coligands, leads to the formation of two novel DyIII dimers, with formulas Dy2(BTFA)4(L)2 (1) and Dy2(TTA)4(L)2 (2) (BTFA = 3-benzoyl-1,1,1-trifluoroacetone and TTA = 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedionate). They exhibit slightly different coordination geometries around DyIII centers and discrepant binuclear motifs – as a result of altering the β-diketonate coligands – which has an impact on the magnetic interactions between metal centers, the local tensor of anisotropy on each DyIII site and their relat…

Magnetic Polyoxometalates:  Anisotropic Antiferro- and Ferromagnetic Exchange Interactions in the Pentameric Cobalt(II) Cluster [Co3W(D2O)2(CoW9O34)2…

2001

The ground-state properties of the pentameric Co(II) cluster [Co(3)W(D(2)O)(2)(CoW(9)O(34))(2)](12-) were investigated by combining magnetic susceptibility and low-temperature magnetization measurements with a detailed inelastic neutron scattering (INS) study on a fully deuterated polycrystalline sample of Na(12)[Co(3)W(D(2)O)(2)(CoW(9)O(34))(2)].46D(2)O. The encapsulated magnetic Co(5) unit consists of three octahedral and two tetrahedral oxo-coordinated Co(II) ions. Thus, two different types of exchange interactions are present within this cluster: a ferromagnetic interaction between the octahedral Co(II) ions and an antiferromagnetic interaction between the octahedral and the tetrahedral…

Hydrothermal Synthesis, Crystal Structure, and Magnetism of Na 2 [Ir(OH) 6 ] and its Dehydration to Na 2 IrO 3

2021

Field-induced single molecule magnet behavior of a dinuclear cobalt(II) complex: a combined experimental and theoretical study.

2020

Two dinuclear cobalt(ii) complexes, [(dmso)CoIIL1(μ-(m-NO2)C6H4COO)CoII(NCS)] (1) and [(dmso)CoIIL2(μ-(m-NO2)C6H4COO)CoII(NCS)] (2) [dmso = dimethylsulfoxide, H2L1 = (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-methoxyphenol) and H2L2 = (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-ethoxyphenol)] have been synthesized and structurally characterized by single-crystal X-ray diffraction, magnetic-susceptibility measurements and various spectroscopic techniques. Each complex contains a cobalt(ii) center with a slightly distorted octahedral geometry and a second cobalt(ii) center with a distorted trigonal prismatic one. To obtain insight into the physical nature of weak non-co…

Long‐Range Order in Layered Perovskite Salts – Structure and Magnetic Properties of [(CH 3 ) 2 CHCH 2 NH 3 ] 2 CuX 4 (X = Cl, Br)

2012

The synthesis, structure, and magnetic properties of two new layered perovskite-type copper halide salts are reported. Dominant ferromagnetic coupling is observed with J/k = 14.58(1) and 21.5(4) K for the Cl and Br salts, respectively. For [(iBA)2CuCl4] (1); (iBA = isobutylammonium): P21/c with a = 13.9481(8) A, b = 7.5061(4) A, c = 7.5133(4) A and β = 102.520(1)° with Z = 4. In this structure, planar CuCl42– ions are linked together into layers of corner-sharing distorted octahedra. Ferromagnetic ordering occurs at Tc = 6.5 K for 1 with spin canting. Hysteresis loops show a coercive field of 2 mT with rapid saturation at 2 K that persists up to T = 9 K. The bromide salt is not isomorphous …

Magnetic coupling and spin topology in linear oxalato-bridged tetranuclear chromium(III)–copper(II) complexes with aromatic diimine ligands

2013

Abstract A novel heterotetranuclear chromium(III)–copper(II) complex of formula {[CrIII(bpy)(ox)2]2CuII2(bpy)2(ox)}·6H2O (1) has been synthesized by the ligand exchange reaction between Ph4P[CrIII(bpy)(ox)2]·H2O and [CuII(bpy)2(NO3)]NO3·MeOH in methanol (bpy = 2,2′-bipyridine; ox2− = oxalate dianion). The X-ray crystal structure of 1 consists of neutral oxalato-bridged CrIII2Cu2II zigzag entities which are formed by the monodentate coordination of two [CrIII(bpy)(ox)2]− mononuclear anionic units through one of its two oxalato groups toward a [CuII2(bpy)2(ox)]2+ dinuclear cationic moiety featuring relatively long axial bonds at the square pyramidal CuII ions. Variable temperature (2.0–300 K)…