scholarly journals Ferro- and Antiferromagnetic Interactions in Oxalato-Centered Inverse Hexanuclear and Chain Copper(II) Complexes with Pyrazole Derivatives

Molecules ◽  
2021 ◽  
Vol 26 (9) ◽  
pp. 2792
Author(s):  
Isabel Castro ◽  
M. Luisa Calatayud ◽  
Marta Orts-Arroyo ◽  
Nicolás Moliner ◽  
Nadia Marino ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Coupling ◽  
Structural Features ◽  
Pyrazole Derivatives ◽  
Spin Hamiltonian ◽  
Temperature Range ◽  
Coordination Center

Two novel copper(II) complexes of formulas {[Cu(4-Hmpz)4][Cu(4-Hmpz)2(µ3-ox-κ2O1,O2:κO2′:κO1′)(ClO4)2]}n (1) and {[Cu(3,4,5-Htmpz)4]2[Cu(3,4,5-Htmpz)2(µ3-ox-κ2O1,O2:κO2′:κO1′)(H2O)(ClO4)]2[Cu2(3,4,5-Htmpz)4(µ-ox-κ2O1,O2:κ2O2′,O1′)]}(ClO4)4·6H2O (2) have been obtained by using 4-methyl-1H-pyrazole (4-Hmpz) and 3,4,5-trimethyl-1H-pyrazole (3,4,5-Htmpz) as terminal ligands and oxalate (ox) as the polyatomic inverse coordination center. The crystal structure of 1 consists of perchlorate counteranions and cationic copper(II) chains with alternating bis(pyrazole)(µ3-κ2O1,O2:κO2′:κO1′-oxalato)copper(II) and tetrakis(pyrazole)copper(II) fragments. The crystal structure of 2 is made up of perchlorate counteranions and cationic centrosymmetric hexanuclear complexes where an inner tetrakis(pyrazole)(µ-κ2O1,O2:κ2O2′,O1′-oxalato)dicopper(II) entity and two outer mononuclear tetrakis(pyrazole)copper(II) units are linked through two mononuclear aquabis(pyrazole)(µ3-κ2O1,O2:κO2′:κO1′-oxalato)copper(II) units. The magnetic properties of 1 and 2 were investigated in the temperature range 2.0–300 K. Very weak intrachain antiferromagnetic interactions between the copper(II) ions through the µ3-ox-κ2O1,O2:κO2′:κO1′ center occur in 1 [J = −0.42(1) cm−1, the spin Hamiltonian being defined as H = −J∑S1,i · S2,i+1], whereas very weak intramolecular ferromagnetic [J = +0.28(2) cm−1] and strong antiferromagnetic [J’ = −348(2) cm−1] couplings coexist in 2 which are mediated by the µ3-ox-κ2O1,O2:κO2′:κO1′ and µ-ox-κ2O1,O2:κ2O2′,O1′ centers, respectively. The variation in the nature and magnitude of the magnetic coupling for this pair of oxalato-centered inverse copper(II) complexes is discussed in the light of their different structural features, and a comparison with related oxalato-centered inverse copper(II)-pyrazole systems from the literature is carried out.

scholarly journals Effect of Nd, Pr substitutional atoms on the magnetic and magnetostrictive properties in (Tb-Dy)(Fe-Co)2 Laves phases

2021 ◽  
Vol 2103 (1) ◽  
pp. 012196
Author(s):  
G A Politova ◽  
M A Ganin ◽  
A B Mikhailova ◽  
D A Morozov ◽  
K E Pankov ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Laves Phase ◽  
Type Structure ◽  
Partial Substitution ◽  
Laves Phases ◽  
Temperature Range ◽  
Homogenizing Annealing ◽  
Arc Melting ◽  
Magnetostrictive Materials

Abstract Polycrystalline TbxDy1-xR0.1Fe2-zCoz (R = Nd, Pr, x = 0.2, 0.3; z = 0, 1.3) cubic Laves phase alloys with MgCu2-type structure were prepared by arc melting followed by homogenizing annealing. The crystal structure, magnetic properties, and magnetostriction have been investigated. Compounds with high values of magnetostrictive susceptibility were found in the temperature range 150-300 K. Compounds with partial substitution of cobalt for iron demonstrate a change in the sign of anisotropic magnetostriction. This work continues the search for magnetostrictive materials with inexpensive neodymium and praseodymium.

Synthesis, Crystal Structure, and Spectroscopic and Magnetic Properties of a Dinuclear Iron(III) Complex Asymmetrically Bridged by a Phenoxo and a Methoxo Group

2005 ◽  
Vol 60 (9) ◽  
pp. 940-944 ◽  
Author(s):  
C. T. Zeyrek ◽  
A. Elmali ◽  
Y. Elerman
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Structural Parameters ◽  
Hamiltonian Operator ◽  
Antiferromagnetic Coupling ◽  
Iron Ions ◽  
Spin Hamiltonian ◽  
Dinuclear Iron ◽  
Super Exchange Interaction

A new dinuclear iron(III) derivative Fe2L(OCH3)Cl2 (L = 1,3-bis[N-(5-chloro-2-hydroxybenzylidene)- 2-aminoethyl]-2-(5-chloro-2-hydroxyphenyl)imidazolidine) has been synthesized, it crystal structure determined and magnetically characterized. The two iron(III) ions are asymmetrically bridged by a phenoxo and a methoxo group and separated by 3.150(2)Å . The magnetic susceptibility of the complex was measured over the range 5 - 349.3 K and the observed data were successfully simulated by the equation based on the spin-Hamiltonian operator , indicating very weak antiferromagnetic coupling between the iron ions with J = −11.3 cm−1. The magnetic and structural parameters of the compound and the nature of the magnetic super-exchange interaction are discussed and compared with data of similar dinuclear iron(III) complexes.

Exchange Interaction in a Dinuclear Iron(III) Complex of a Heptadentate Schiff Base: Synthesis, Crystal Structure and Magnetic Properties

2005 ◽  
Vol 60 (7) ◽  
pp. 727-731 ◽  
Author(s):  
C. T. Zeyrek ◽  
A. Elmali ◽  
Y. Elerman
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Schiff Base ◽  
Exchange Interaction ◽  
Hamiltonian Operator ◽  
Antiferromagnetic Coupling ◽  
Iron Ions ◽  
Spin Hamiltonian ◽  
Dinuclear Iron

Synthesis, crystallographic characterization and magnetic properties of the new dinuclear iron(III) complex Fe2L(OCH3)Cl2 (L=1,3-bis[N-(3,5-dichloro-2-hydroxybenzylidene)-2-aminoethyl]-2-(3,5- dichlo ro-2-hydroxyphenyl)imidazolidine) are reported. The structure consists of dinuclear units. The two iron(III) atoms are asymmetrically bridged by a phenoxo and a methoxo group. The iron(III) centers are separated by 3.133(2) Å . The Magnetic susceptibility of the complex was measured over the range 5 - 298 K and the observed data were successfully simulated by the equation based on the spin-Hamiltonian operator H = −JS⃗1.S⃗2. Magnetic susceptibility measurements indicate very weak antiferromagnetic coupling between the iron ions with J = −10.8 cm−1 and g = 2.0.

Magnetic coupling in discrete cyano-bridged MnIII-FeIII motifs: Synthesis, crystal structure, magnetic properties and theoretical study

2010 ◽  
Vol 39 (20) ◽  
pp. 5028 ◽  
Author(s):  
Diana Visinescu ◽  
Luminita Marilena Toma ◽  
Joan Cano ◽  
Oscar Fabelo ◽  
Catalina Ruiz-Pérez ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Theoretical Study ◽  
Magnetic Coupling

scholarly journals Effect of isovalent substitution on the crystal structure and properties of two-slab indates BaLa2−xSmxIn2O7

2020 ◽  
Vol 18 (1) ◽  
pp. 1294-1303
Author(s):  
Yuri Titov ◽  
Nadezhda Belyavina ◽  
Mykola Slobodyanik ◽  
Olesya Nakonechna ◽  
Nataliia Strutynska ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Materials Science ◽  
Rietveld Method ◽  
Structural Features ◽  
Complete Characterization ◽  
Isomorphic Substitution ◽  
X Ray ◽  
Isovalent Substitution ◽  
Substitution Degree

AbstractExploring the effect of isomorphic substitution of atoms on crystal structure and features of oxide compounds is one of the main tasks of modern materials science. This paper deals with the La/Sm isovalent substitution in a two-slab perovskite-like BaLa2In2O7 structure and its effect on the structural features and magnetic properties of BaLa2−xSmxIn2O7 indates synthesized. A complete characterization including data of scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), structural calculations (Rietveld method), second optical harmonic generation of the laser radiation, calculations of valence bond sums (VBS), and magnetic susceptibility data of phases obtained is presented. The existence region of BaLa2−xSmxIn2O7 solid solutions with a two-slab perovskite-like structure (0 ≤ x ≤ 1.8) was established, and their coordinate parameters were refined. The character of barium and RE atoms distribution in BaLa2−xSmxIn2O7 structure has determined, and the correlation between substitution degree of lanthanum atoms and the length of Ln–O2 interblock distance has revealed. The magnetic properties of BaLa2−xSmxIn2O7 were considered in terms of the crystal field effect.

scholarly journals Кристаллическая структура и магнитные характеристики твердых растворов Mn-=SUB=-1-x-=/SUB=-Fe-=SUB=-x-=/SUB=-NiGe

2021 ◽  
Vol 63 (3) ◽  
pp. 393
Author(s):  
Г.С. Римский ◽  
К.И. Янушкевич ◽  
Н.М. Белозорева ◽  
Д.П. Козленко ◽  
А.В. Руткаускас
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Phase Transformation ◽  
Neutron Diffraction ◽  
Magnetic Order ◽  
Hexagonal Structure ◽  
Orthorhombic Structure ◽  
X Ray ◽  
Temperature Range ◽  
Magnetic Disorder

Substitutional solid solutions Mn1-xFexNiGe (0.05≤x≤1.00) were synthesized. The crystal structure in the temperature range of 20 - 300 K has been studied by X-ray and neutron diffraction. At T = 200 K, a phase transformation from a hexagonal structure of the Ni2In type to an orthorhombic structure (S.G. Pnma) has been observed. The magnetic properties of these compounds were also investigated in the temperature range of 5 - 300 K and external magnetic fields up to 10 T. The temperature of the "magnetic order - magnetic disorder" phase transformation was found to decrease from 272 to 132 K with an increase in concentration x from 5 to 30 mol%.

scholarly journals Heterobimetallic One-Dimensional Coordination Polymers MICuII (M = Li and K) Based on Ferromagnetically Coupled Di- and Tetracopper(II) Metallacyclophanes

2018 ◽  
Vol 4 (3) ◽  
pp. 38 ◽  
Author(s):  
Tamyris T. da Cunha ◽  
Willian X. C. Oliveira ◽  
Emerson F. Pedroso ◽  
Francesc Lloret ◽  
Miguel Julve ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Coordination Polymers ◽  
Complex Anion ◽  
Spin Hamiltonian ◽  
One Dimensional ◽  
Carboxylate Oxygen ◽  
Out Of Plane ◽  
Ferromagnetic Interactions ◽  
Oxygen Atoms

The synthesis, crystal structure and magnetic properties of the coordination polymers of formula [EDAP{Li6(H2O)8[(Cu2(μ-mpba)2)2(H2O)2]}]n (1) and [(EDAP)2{K(H2O)4[Cu2(μ-mpba)2(H2O)2]}Cl·2H2O]n (2), in which mpba = N,N′-1,3-phenylenebis(oxamate) and EDAP2+ = 1,1′-ethylenebis(4-aminopyridinium) are described. Both compounds have in common the presence of the [Cu2(mpba)2]4− tetraanionic unit which is a [3,3] metallacyclophane motif in which the copper(II) ions are five-coordinate in a distorted square pyramidal surrounding. The complex anion in 1 is dimerized through double out-of-plane copper to outer carboxylate-oxygen atoms resulting in the centrosymmetric tetracopper(II) fragment [Cu4(μ-mpba)4(H2O)2]8− which act as a ligand toward six hydrated lithium(I) cations leading to anionic ladder-like double chains whose charge is neutralized by the EDAP2+ cations. In the case of 2, each dicopper(II) entity acts as a ligand towards tetraquapotassium(I) units to afford anionic zig zag single chains of formula {K(H2O)4[Cu2(μ-mpba)2(H2O)2]}n3n− plus EDAP2+ cations and non-coordinate chloride anions. Cryomagnetic measurements on polycrystalline samples 1 and 2 show the occurrence of ferromagnetic interactions between the copper(II) ions across the –Namidate–(C–C–C)phenyl–Namidate– exchange pathway [J = +10.6 (1) and +8.22 cm−1 (2)] and antiferromagnetic ones through the double out-of-plane carboxylate-oxygen atoms [j = −0.68 cm−1 (1), the spin Hamiltonian being defined as H = − J ( S C u 1 · S C u 2 + S C u 2 i · S C u 1 i ) − j ( S C u 2 · S C u 2 i ) ].

Crystal Structures and Peculiar Magnetic Properties of α- and γ-Al2O3 Powders

1997 ◽  
Vol 11 (26n27) ◽  
pp. 1169-1174 ◽  
Author(s):  
R. S. Liu ◽  
W. C. Shi ◽  
Y. C. Cheng ◽  
C. Y. Huang
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Crystal Structures ◽  
Room Temperature ◽  
Magnetic Behavior ◽  
Temperature Range ◽  
Diamagnetic Signal

The crystal structure and magnetic properties of the α- Al2O 3 and γ- Al2O 3 samples were investigated. The α- Al2O 3 and γ- Al2O 3 powders have the trigonal and cubic symmetries, respectively. Moreover, the α- Al2O 3 powders have better crystallinity than γ- Al2O 3 material. A peculiar magnetic behavior in these two materials was found. The weak diamagnetic signal appeared at the temperature range between room temperature and 100 K. Moreover, both materials have antiferromagnetic-like transitions at the temperature range between 30 K and 100 K. The materials changed to paramagnetic-like behavior at the temperature lower than 30 K. Based on our studies, we did not find any superconducting diamagnetic signal at the temperature range from 300 K to 5 K.

Magnetic Properties and Structure of Metallic Multilayers Investigated by NMR

1997 ◽  
Vol 475 ◽  
Author(s):  
P. Panissod ◽  
C. Mèny ◽  
M. Wójcik ◽  
E. Jedryka
Keyword(s):  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Magnetic Coupling ◽  
Structural Features ◽  
Magnetic Multilayers ◽  
Topological Order ◽  
Metallic Multilayers ◽  
Local Magnetization ◽  
Structural Investigations ◽  
Electronic Moment

ABSTRACTAs a probe of the short range chemical and topological order, NMR is useful for structural investigations of magnetic multilayers (interface structure and composition, bulk phases and defects, strains). The magnetic character of the raw data makes it also possible to study local magnetic properties of these composite systems, and to correlate them with local structural features. The hyperfine field is the first output of an NMR experiment which gives a direct insight on the local magnetization in ferromagnets. NMR is also sensitive to the restoring torque exerted on the electronic moment by the local magnetic anisotropy and/or exchange and dipolar couplings. Combined with the fact that the various parts of a sample (atomic planes involved in the interfaces, bulk phases and bulk defects) can be discriminated in the spectra, the magnetic information contained in the data allows to probe quantitatively or, at least, to place on a relative scale, the different magnetic responses of the different parts of a sample. We present here the relevant results which we have obtained in the course of our investigations of Co based multilayers and spin valves (interface magnetic profiles, inhomogeneities of magnetic anisotropy and of magnetic coupling).

Synthesis, Crystal Structure and Properties of a New Lanthanide Pyridine-2,4,6-tricarboxylato Coordination Polymer

2011 ◽  
Vol 66 (6) ◽  
pp. 570-576
Author(s):  
Jian-Li Lin ◽  
Wei Xu ◽  
Li Zhao ◽  
Yue-Qing Zheng
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Coordination Polymer ◽  
Visible Region ◽  
Tricarboxylic Acid ◽  
Structure And Properties ◽  
Temperature Dependent ◽  
Coordination Modes ◽  
Temperature Range ◽  
Trigonal Prismatic

A new lanthanide pyridine-2,4,6-tricarboxylato coordination polymer, [Dy2(H2O)5(ptc)2]·H2O (H3ptc = pyridine-2,4,6-tricarboxylic acid), was hydrothermally synthesized. The complex exhibits both mono-capped square antiprismatic DyNO8 chromophores and 4,4ʹ-bicapped trigonal prismatic DyNO7 chromophores, which are interconnected through ptc3− anions in μ3η6 and μ4η6 coordination modes to achieve a new 3D MOF of an unprecedented topology of (4 · 63 · 82)(63) type. This Dy(III) complex exhibits a characteristic luminescence in the visible region upon excitation at 300 nm. The temperature-dependent magnetic properties of the Dy(III) complex were investigated in the temperature range of 2 - 300 K.

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