Search results for "magnetism."
showing 10 items of 1879 documents
Synthesis, crystal structure and magnetic properties of H2tppz[ReCl6] and [Cu(bpzm)2(μ-Cl)ReCl3(μ-ox)Cu(bpzm)2(μ-ox)ReCl3(μ-Cl)]n.
2015
Two new Re(iv) compounds of formulae H2tppz[ReCl6] (1) and [Cu(bpzm)2(μ-Cl)ReCl3(μ-ox)Cu(bpzm)2(μ-ox)ReCl3(μ-Cl)]n (2) [tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine and bpzm = bis(pyrazolyl-1-yl)methane] have been prepared and their crystal structures determined by X-ray diffraction on single crystals. Compound 1 is a mononuclear species whose structure consists of octahedral hexachlororhenate(iv) anions and diprotonated H2tppz(2+) cations which are arranged in the unit cell as alternating anionic and cationic layers, held together by electrostatic forces. The structure of 2 is made up of alternating [Cu(1)(bpzm)2](2+) and [(ox)ReCl3(μ-Cl)Cu(2)(bpzm)2(μ-Cl)ReCl3(ox)](2-) entities interlinked …
Oxalate-Based Soluble 2D Magnets: The Series [K(18-crown-6)]3[MII3(H2O)4{MIII(ox)3}3] (MIII = Cr, Fe; MII = Mn, Fe, Ni, Co, Cu; ox = C2O42−; 18-crown…
2008
The synthesis and magnetic properties of the oxalate-based molecular soluble magnets with general formula [K(18-crown-6)] 3[M (II) 3(H 2O) 4{M (III)(ox) 3} 3] (M (III) = Cr, Fe; M (II) = Mn, Fe, Ni, Co, Cu; ox = C 2O 4 (2-)) are here described. All the reported compounds are isostructural and built up by 2D bimetallic networks formed by alternating M (III) and M (II) ions connected through oxalate anions. Whereas the Cr (III)M (II) derivatives behave as ferromagnets with critical temperatures up to 8 K, the Fe (III)M (II) present ferri- or weak ferromagnetic ordering up to 26 K.
2D and 3D bimetallic oxalate-based ferromagnets prepared by insertion of different FeIII spin crossover complexes
2010
The syntheses, structures and magnetic properties of the compounds of formula [Fe(III)(5-NO(2)sal(2)-trien)][Mn(II)Cr(III)(ox)(3)]·CH(3)NO(2).0.5H(2)O (1) and [Fe(III)(5-CH(3)Osal(2)-trien)][Mn(II)Cr(III)(ox)(3)] (2) are reported. The structure of 1, that crystallizes in the P2(1) chiral space group, presents a 2D honeycomb anionic layer formed by Mn(II) and Cr(III) ions linked through oxalate ligands and a cationic layer of [Fe(III)(5-NO(2)sal(2)-trien)](+) complexes intercalated between the 2D oxalate network. The structure of 2, that crystallizes in the Pna2(1) acentric space group, presents a 3D achiral anionic network formed by Mn(II) and Cr(III) ions linked through oxalate ligands wit…
The first example of a hetero-tetranuclear [(VO)Gd](2) complex: synthesis, crystal structure and magnetic properties of [VOLGd(hfa)(2)CH(3)OH](2).2CH…
2005
A cyclic tetranuclear [VIVO–GdIII]2 complex with VO and Gd ions alternately arrayed, behaves, from the magnetic point of view, as two independent dinuclear entities each having a S = 4 ground state, as a consequence of an active and ferromagnetic VO–Gd interaction through the double phenoxo bridge and a magnetically inactive VO–Gd interaction through the amide bridge.
2D and 3D Anilato-Based Heterometallic M(I)M(III) Lattices: The Missing Link
2015
The similar bis-bidentate coordination mode of oxalato and anilato-based ligands is exploited here to create the first examples of 2D and 3D heterometallic lattices based on anilato ligands combining M(I) and a M(III) ions, phases already observed with oxalato but unknown with anilato-type ligands. These lattices are prepared with alkaline metal ions and magnetic chiral tris(anilato)metalate molecular building blocks: [M(III)(C6O4X2)3](3-) (M(III) = Fe and Cr; X = Cl and Br; (C6O4X2)(2-) = dianion of the 3,6-disubstituted derivatives of 2,5-dihydroxy-1,4-benzoquinone, H4C6O4). The new compounds include two very similar 2D lattices formulated as (PBu3Me)2[NaCr(C6O4Br2)3] (1) and (PPh3Et)2[KF…
A unique single carboxylate-bridged spin-frustrated chiral Mn(II) metallatriangle.
2010
The reaction between Hmbpymca ligand (prepared in situ from the hydrolysis of 5-methyl-4-cyano-bispyrimidine with NaOH and further neutralization with 2 M HCl) and Mn(ClO(4))(2)·4H(2)O in 1:1 molar ratio afforded the triangulo-trimanganese(II) complex [Mn(3)(bpymca)(3)(H(2)O)(6)]Cl(3)·6H(2)O 1. The chloride anions in this complex come from the HCl used in the neutralization process. The molecular structure of 1 consists of cationic molecular triangles [Mn(3)(μ-mbpymca)(3)(H(2)O)(6)](3+) with C(3) symmetry, chloride anions and crystallization water molecules, all of them involved in an extensive network of hydrogen bonds, leading to a chiral network. Within the [Mn(3)(μ-mbpymca)(3)(H(2)O)(6)…
A triple-bridged azido-Cu(II) chain compound fine-tuned by mixed carboxylate/ethanol linkers displays slow-relaxation and ferromagnetic order: synthe…
2014
A new azido-Cu(II) compound, [Cu(4-fba)(N3)(C2H5OH)] (4-fba = 4-fluorobenzoic acid) (1), has been synthesized and characterized. The X-ray crystal structure analysis demonstrates that only one crystallographically independent Cu(II) ion in the asymmetric unit of 1 exhibits a stretched octahedral geometry in which two azido N atoms and two carboxylic O atoms locate in the equatorial square, while two ethanol O atoms occupy the apical positions, forming a 1D Cu(II) chain with an alternating triple-bridge of EO-azido, syn,syn-carboxylate, and μ2-ethanol. The title compound consists of ferromagnetically interacting ferromagnetic chains, which exhibit ferromagnetic order (Tc = 7.0 K). The strong…
The Iron Hydrido Complex [FeH(dppe)2]+: Solution and Solid-State Reactivity with Dinitrogen
2006
The blue compound [FeH(dppe)2]BPh4 (1) (dppe = 1,2-bis(diphenylphosphino)ethane) is investigated by optical absorption, vibrational, NMR and Mossbauer spectroscopy as well as magnetic susceptibility measurements. In the solid state, 1 is found to be paramagnetic (S=1) whereas in tetrahydrofuran (thf) solution it is diamagnetic. Importantly, 1 reacts with dinitrogen in thf solution and in the solid state to give the yellow and green dinitrogen complexes 2a and 2b, respectively, both of which have the formula [FeH(N2)(dppe)2]BPh4. Apart from their colour and optical spectroscopic properties, the dinitrogen compounds 2a and 2b also differ in their magnetic, Mossbauer and vibrational properties…
A T‐Shaped μ 3 ‐Oxido Trinuclear Iron Cluster with High Easy‐Plane Anisotropy: Structural and Magnetic Characterization
2008
The synthesis, crystal structure and magnetochemical characterization of a new μ-oxido trinuclear iron cluster (oldnomenclature: μ-oxo trinuclear iron cluster), [Fe3(μ3-O)(μ2-CH3O)2(μ2-CH3COO)2(phen)2Cl3], is reported. The reaction of hydrated FeCl3 with sodium acetate and 1,10-phenanthroline in a mixture of methanol and acetonitrile afforded crystals suitable for X-ray crystallographic determination. The new compound crystallizes in the tetragonal I41/a space group (a = b = 13.6322 A, c = 37.3538 A, Z = 8, V = 6941.7 A3). The core of the complex is an isosceles triangle bridged by a μ3-O ion with a rare T-shaped geometry. The chloride ions are bound terminally, and the phenanthroline ligan…
Insertion of a [Fe II (pyimH) 3 ] 2+ [pyimH = 2‐(1 H ‐Imidazol‐2‐yl)pyridine] Spin‐Crossover Complex Inside a Ferromagnetic Lattice Based on a Chiral…
2015
The insertion of the [FeII(pyimH)3]2+ [pyimH = 2-(1H-imidazol-2-yl)pyridine] spin-crossover complex into a ferromagnetic bimetallic oxalate network affords the hybrid compound [FeII(pyimH)3][MnIICrIII(ox)3]2·X (ox = C2O42–). This spin-crossover complex templates the growth of crystals formed by a chiral 3D oxalate network. The magnetic properties of this hybrid magnet show the coexistence of long-range ferromagnetic ordering at 4.5 K and a spin crossover of the intercalated [FeII(pyimH)3]2+ complex above 250 K. The compound presents a light-induced excited spin-state trapping (LIESST) effect below 60 K although with limited photoconversion (less than 8 %).