Two-Dimensional Nitronyl Nitroxide–Cu Networks Based on Multi-Dentate Nitronyl Nitroxides: Structures and Magnetic Properties

Two multi-dentate nitronyl nitroxide radicals, namely, bisNITPhPy ([5-(4-pyridyl)-1,3-bis(1′-oxyl-3′-oxido-4′,4′,5′,5′-tetramethyl-4,5-hydro-1H-imidazol-2-yl)]benzene) and NIT-3Py-5-4Py (2-{3-[5-(4-pyridyl)]pyridyl}-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide), were assembled with CuII ions to obtain two-dimensional heterospin 2p–3d coordination polymers [Cu7(hfac)14(bisNITPhPy)2]n (1) and [Cu2(hfac)4(NIT-3Py-5-4Py)]n (2) (hfac: hexafluoroacetylacetonate). In both compounds, the bisNITPhPy and NIT-3Py-5-3Py radicals acted as pentadentate and tetradentate ligands, respectively, to connect with CuII ions, generating a 2D layer structure. The analysis of the magnetic behavior indicated that strong antiferromagnetic coupling and ferromagnetic interaction (J = 17.1 cm−1) coexisted in 1. For 2, there were ferromagnetic couplings between the CuII ion and NO group, as well as the CuII ion and radical via the pyridine ring with J1 = 32.8 and J2 = 2.2 cm−1, respectively.

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Two-dimensional Co–Ln networks bridged by phenyl pyrimidyl substituted nitronyl nitroxides: structural and magnetic properties

Dalton Transactions ◽

10.1039/c8dt00270c ◽

2018 ◽

Vol 47 (13) ◽

pp. 4672-4677 ◽

Cited By ~ 8

Author(s):

Guifang Sun ◽

Jianni Guo ◽

Meng Yang ◽

Lu Xi ◽

Licun Li ◽

...

Keyword(s):

Magnetic Properties ◽

Two Dimensional ◽

Nitronyl Nitroxide ◽

Nitronyl Nitroxides ◽

Structural And Magnetic Properties

Two novel 2D Co–Ln complexes have been obtained, which represent the first examples of nitronyl nitroxide bridged 2D Co–Ln complexes.

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Nitronyl Nitroxide Biradical-Based Binuclear Lanthanide Complexes: Structure and Magnetic Properties

Magnetochemistry ◽

10.3390/magnetochemistry6040048 ◽

2020 ◽

Vol 6 (4) ◽

pp. 48

Author(s):

Lu Xi ◽

Jing Han ◽

Xiaohui Huang ◽

Licun Li

Keyword(s):

Magnetic Properties ◽

Magnetic Relaxation ◽

Lanthanide Complexes ◽

Magnetic Data ◽

Antiferromagnetic Coupling ◽

Zero Field ◽

Nitronyl Nitroxide ◽

Ferromagnetic Exchange ◽

Binuclear Structure ◽

Slow Magnetic Relaxation

Employing a new nitronyl nitroxide biradical NITPhPzbis(NITPhPzbis = 5-(1-pyrazolyl)-1,3-bis(1’-oxyl-3’-oxido-4’,4’,5’,5’-tetramethyl-4,5-hydro-1H-imidazol-2-yl)benzene), a series of 2p-4f complexes [Ln2(hfac)6(H2O)(NITPhPzbis)] (LnIII = Gd1, Tb2, Dy3; hfac = hexafluoroacetylacetonate) were successfully synthesized. In complexes 1–3, the designed biradical NITPhPzbis coordinates with two LnIII ions in chelating and bridging modes to form a four-spin binuclear structure. Direct-current magnetic study of Gd analogue indicates that ferromagnetic exchange exists between the Gd ion and the radical while antiferromagnetic coupling dominates between two mono-radicals. Dynamic magnetic data show that the χ” signals of complex 3 exhibit frequency dependence under zero field, demonstrating slow magnetic relaxation behavior in complex 3. And the estimated values of Ueff and τ0 are about 8.4 K and 9.1 × 10−8 s, respectively.

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A Mn(II) Coordination Polymer with Sulfate and trans-1,2-Bis(4- pyridyl)ethylene Bridges: Synthesis, Structure, Magnetic and Ferroelectric Properties

Zeitschrift für Naturforschung B ◽

10.5560/znb.2013-3119 ◽

2013 ◽

Vol 68 (8) ◽

pp. 877-884 ◽

Cited By ~ 4

Author(s):

Wei Xu ◽

Jian-Li Lin

Keyword(s):

Coordination Polymer ◽

Remanent Polarization ◽

Ferroelectric Properties ◽

Magnetic Behavior ◽

Title Complex ◽

Spectroscopic Measurement ◽

Antiferromagnetic Coupling ◽

Monoclinic Space Group ◽

Two Dimensional ◽

Ir Spectroscopic

Reaction of MnSO4 and trans-1,2-bis(4-pyridyl)ethene (bpe) results in a new coordination polymer, [Mn(H2O)2(bpe)(SO4)]·H2O. The title complex crystallizes in the polar monoclinic space group C2. The octahedrally coordinated Mn atoms are bridged by sulfate anions and bpe ligands to form two-dimensional sheets with (42·63·8) topology. This polar complex displays ferroelectricity with a remanent polarization (2Pr) of ca. 0:5779 μC cm-2, a coercive field (2Ec) of 8:8 kV cm-1, and a saturation of the spontaneous polarization (PS) of ca. 0:4177 μC cm-2. The magnetic behavior of the title complex suggests significant antiferromagnetic coupling interactions between Mn(II) ions bridged by sulfate anions. Furthermore, the title complex was subjected to elemental analysis, IR spectroscopic measurement and thermal analysis.

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Ferromagnetic Intermolecular Interaction and Crystal Structure of α-Nitronyl Nitroxide

MRS Proceedings ◽

10.1557/proc-173-33 ◽

1989 ◽

Vol 173 ◽

Cited By ~ 3

Author(s):

Kunio Awaga ◽

Tamotsu Inabe ◽

Yusei Maruyama

Keyword(s):

Crystal Structure ◽

Temperature Dependence ◽

Intermolecular Interaction ◽

Magnetic Coupling ◽

Two Dimensional ◽

Nitronyl Nitroxide ◽

Magnetic Susceptibilities ◽

X Ray ◽

Nitronyl Nitroxides ◽

Coulomb Attraction

ABSTRACTThe temperature dependence of the magnetic susceptibilities for several ±-nitronyl nitroxides have been measured. It is found that the intermolecular magnetic coupling in these radical crystals changes from antiferromagnetic to ferromagnetic depending on the substituents at ±-position. X-Ray crystal analysis and MO calculation have been carried out on the ferromagnetic ±-nitronyl nitroxide, 2-(4-nitrophenyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazolyl-1-oxy 3-oxide, revealing a two-dimensional ferromagnetic network linked by the Nδ+...0δ− Coulomb attraction.

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Giant Magnetoresistance and Soft Magnetic Properties of NiFeCo/Cu Multilayers

MRS Proceedings ◽

10.1557/proc-313-271 ◽

1993 ◽

Vol 313 ◽

Cited By ~ 6

Author(s):

S. Tsunashima ◽

M. Jimbo ◽

T. Kanda ◽

S. Goto ◽

S. Uchiyama

Keyword(s):

Magnetic Properties ◽

Giant Magnetoresistance ◽

Layer Structure ◽

Structural Characteristics ◽

Buffer Layers ◽

Antiferromagnetic Coupling ◽

Soft Magnetic Properties ◽

Transmission Electron Micrograph ◽

Soft Magnetic ◽

Cross Sectional

ABSTRACTGiant Magnetoresistance (GMR) and soft magnetic properties together with their structural characteristics were investigated for Ni66Fe16Co18/Cu Multilayers. The Multilayers were prepared by the conventional rf sputtering method on glass or Si substrates using various buffer layers including Fe, NiFeCo, NiFe and CoZr. Although Most of the multilayers exhibited (111) preferred orientation, Fe buffered multilayers showed a considerable (200) X-ray diffraction peak at Cu thicknesses around 1 nm and 2.2 nm which corresponded to the peak positions of GMR. By using fee or amorphous underlayers the (200) diffraction intensity decreased while antiferromagnetic coupling strength was much reduced. Cross-sectional transmission electron micrograph revealed that the (100) oriented multilayer was grown on the (100) oriented Fe underlayer. By controlling the crystal orientation and the layer structure, significantly large magnetoresistance ratio of more than 10 % can be achieved in a field as low as 30 Oe.

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Crystal structure and Hirshfeld surface analysis of 2,2′′′,6,6′′′-tetramethoxy-3,2′:5′,3′′:6′′,3′′′-quaterpyridine

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s205698901901274x ◽

2019 ◽

Vol 75 (10) ◽

pp. 1511-1514

Author(s):

Suk-Hee Moon ◽

Jinho Kim ◽

Ki-Min Park ◽

Youngjin Kang

Keyword(s):

Surface Analysis ◽

Pyridine Ring ◽

Crystal Packing ◽

Layer Structure ◽

Hirshfeld Surface ◽

Hirshfeld Surface Analysis ◽

Dihedral Angles ◽

Stacking Interactions ◽

Two Dimensional ◽

Compound C

In the title compound, C24H22N4O4, the four pyridine rings are tilted slightly with respect to each other. The dihedral angles between the inner and outer pyridine rings are 12.51 (8) and 9.67 (9)°, while that between inner pyridine rings is 20.10 (7)°. Within the molecule, intramolecular C—H...O and C—H...N contacts are observed. In the crystal, adjacent molecules are linked by π–π stacking interactions between pyridine rings and weak C—H...π interactions between a methyl H atom and the centroid of a pyridine ring, forming a two-dimensional layer structure extending parallel to the ac plane. Hirshfeld surface analysis and two-dimensional fingerprint plots indicate that the most important contributions to the crystal packing are from H...H (52.9%) and H...C/C...H (17.3%) contacts.

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Electronic Structure and Magnetic Properties of Transition Metal Doped Silicon Carbide

MRS Proceedings ◽

10.1557/proc-690-f6.8 ◽

2001 ◽

Vol 690 ◽

Author(s):

M. S. Miao ◽

Walter R. L. Lambrecht

Keyword(s):

Silicon Carbide ◽

Magnetic Properties ◽

Density Functional ◽

Magnetic Behavior ◽

Antiferromagnetic Coupling ◽

Ferromagnetic Coupling ◽

Atomic Sphere ◽

Lmto Method ◽

Sphere Approximation ◽

Metal Doped

ABSTRACTThe magnetic properties of cubic (3C) silicon carbide (SiC) doped by first row transition metals (TM) are studied within the local spin density functional approach using the linearized muffin-tin orbital (LMTO) method in the atomic sphere approximation (ASA). The magnetic properties are found to depend strongly on the doping site. For the preferred doping site (Si), Cr and Mn exhibit the most pronounced magnetic behavior with Cr favoring ferromagnetic coupling and Mn antiferromagnetic coupling.

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A Crystallographic Study of a Novel Tetrazolyl-Substituted Nitronyl Nitroxide Radical

Crystals ◽

10.3390/cryst8090334 ◽

2018 ◽

Vol 8 (9) ◽

pp. 334 ◽

Cited By ~ 2

Author(s):

Vasily Romanov ◽

Irina Bagryanskaya ◽

Dmitry Gorbunov ◽

Nina Gritsan ◽

Elena Zaytseva ◽

...

Keyword(s):

Nitroxide Radical ◽

Nitronyl Nitroxide ◽

Nitronyl Nitroxide Radical ◽

Ferromagnetic Interaction ◽

Nitronyl Nitroxides ◽

Crystallographic Study ◽

Intermolecular Contacts ◽

Directed Synthesis ◽

Material Sciences ◽

Stable Radicals

Spin-labelled compounds are widely used in chemistry, physics, biology, and material sciences, but the directed synthesis of some functionalized organic radicals is still a challenge. We succeeded in the preparation of a tetrazolyl-substituted nitronyl nitroxide radical in pure crystalline form. According to the single-crystal X-ray data, intra- (NH…O, 2.43 Å) and inter-molecular hydrogen bonds (NH…O, 1.91 Å) are formed between NH groups of the tetrazole cycles and O atoms of the paramagnetic moieties. The intermolecular H-bonds connect the molecules forming chains along the a-axis. Moreover, there are short intermolecular contacts between the O atoms (3.096 Å) and between the O and C atoms (3.096 Å) of the nitronyl nitroxide moieties within the chain. The spin-unrestricted broken-symmetry calculations performed at the BS-UB3LYP/def2-TZVP level of theory predicted a sufficient ferromagnetic interaction (J ≈ 20 cm–1) between the adjacent radicals inside the chain, but a weak antiferromagnetic interaction (−J ≤0.2 cm−1) between the nearest radicals belonging to the different chains. Thus, a rare case when stable radicals, the tetrazolyl-substituted nitronyl nitroxides, are ordered into ferromagnetic chains was revealed; an investigation of the magneto-structural correlations inherent in the nitroxide radical will demand a special experiment in the sub-Kelvin regime.

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Magnetic Properties of Diaquabis(phenoxyacetato)manganese(II) and Related Complexes

Zeitschrift für Naturforschung A ◽

10.1515/zna-1984-0410 ◽

1984 ◽

Vol 39 (4) ◽

pp. 371-375 ◽

Cited By ~ 3

Author(s):

Tetsuo Asaji ◽

Kazumasa Aoki ◽

Daiyu Nakamura

Keyword(s):

Phase Transition ◽

Magnetic Properties ◽

Magnetic Susceptibility ◽

Temperature Region ◽

Magnetic Phase ◽

Two Dimensional ◽

Ferromagnetic Interaction ◽

Magnetic Susceptibilities ◽

Sharp Maximum ◽

Ordered State

The magnetic susceptibilities of diaquabis(phenoxyacetato)manganese(II), diaquabis(p-chlorophenoxyacetato) manganese(II), and diaquabis(phenoxyacetato)cobalt(II) were determined in a temperature region below 77 K. The temperature dependence of the magnetic susceptibility observed for the first two manganese(II) complexes shows a broad maximum near 2 K. which can be interpreted as arising from two-dimensional Heisenberg antiferromagnets with S = 5/2. The magnetic susceptibility of the cobalt(II) complex obeys the Curie-Weiss law showing the presence of a ferromagnetic interaction between neighboring cobalt(II) ions. For diaquabis( phenoxyacetato)manganese(II), a magnetic phase transition from a disordered to an antiferromagnetic ordered state was located at 1.633 ± 0.005 K from the sharp maximum of the magnetic susceptibility.

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