Search results for "Antiferromagnet"
showing 10 items of 506 documents
Towards Molecular Conductors with a Spin‐Crossover Phenomenon:Crystal Structures, Magnetic Properties and Mössbauer Spectra of[Fe(salten)Mepepy][M(dm…
2005
Three new iron(III) compounds of formula [Fe(salten)Mepepy][M(dmit)2]·CH3CN (M = Ni, Pd, Pt; H2salten = 4-azaheptamethylene-1,7-bis(salicylideneiminate); Mepepy = 1-(pyridin-4-yl)-2-(N-methylpyrrol-2-yl) ethane; dmit2– = 1,3-dithiole-2-thione-4,5-dithiolato) have been synthesised and the crystal structure of each compound has been solved at different temperatures. The structures consist of alternating layers of [M(dmit)2]– units and [Fe(salten)Mepepy] cations. In the Ni compound photo-isomerisation of the Mepepy ligand can be observed in dichloromethane solution. The temperature dependence of the magnetic susceptibility of the compounds reveals a gradual S = 5/2 blabla S = 1/2 spin crossove…
Unexpected magnetic topology in the heterobimetallic [ReIVBr4(μ-ox)CuII(bpy)2] compound
2011
Abstract A novel oxalato-bridged rhenium(IV)-copper(II) compound, namely [ReIVBr4(μ-ox)CuII(bpy)2] (1), has been obtained by reacting (PPh4)2[ReBr4(ox)] with Cu(CF3SO3)2 and 2,2′-bpy in CH3CN, and its crystal structure determined by single-crystal X-ray diffraction. Intermolecular Br⋯Br interactions and nonbonding Cu⋯Br type contacts between the heterobimetallic dinuclear units lead to a two-dimensional supramolecular structure. Compound 1 behaves magnetically as a [ReIVCuII]2 tetranuclear species with weak antiferromagnetic interactions through the oxalato bridge and intermolecular Br⋯Br contacts.
Spin canting in an unprecedented three-dimensional pyrophosphate- and 2,2'-bipyrimidine-bridged cobalt(II) framework.
2008
The three-dimensional cobalt(ii) compound of formula {[Co(2)(P(2)O(7))(bpym)(2)].12H(2)O}(n), where the pyrophosphate and 2,2'-bipyrimidine act as bridging ligands, is a new example of a spin-canted antiferromagnet with T(c) = 19 K.
A Discrete μ 4 ‐Oxido Tetranuclear Iron(III) Cluster
2012
Reaction of a Schiff base ligand derived from salicyloyl hydrazide and diacetyl monooxime (H2L) with a triangular μ3-oxido-centered [Fe3(μ3-O)]7+ core yields a new tetranuclear iron(III) complex. FeIII4(μ4-O) crystallizes in the triclinic space group P. Structural studies reveal that this tetranuclear iron(III) complex is a new structure type of an uncharged (alkoxido)(oxido)iron(III) cluster in which the four iron(III) ions are located at the corners of a distorted tetrahedron. A study of the magnetic properties supports the presence of antiferromagnetic interactions through the central μ4-oxido ion as well as the μ2-methoxy groups present, giving an an S = 0 ground state. Mossbauer spectr…
( 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…
X-Ray structure of [ReCl4(μ-ox)Cu(pyim)2]: a new heterobimetallic ReIVCuIIferrimagnetic chain
2008
A new heterobimetallic Re(IV)Cu(II) compound has been prepared and its crystal structure determined by single-crystal X-ray diffraction; magnetic susceptibility measurements show that this compound behaves as a ferrimagnetic chain with significant antiferromagnetic interactions between Re(IV) and Cu(II) metal ions.
In situ generation of Ph3PO in cyanido-bridged heterometallic {FeIIILnIII}2 molecular squares (Ln = Eu, Sm)
2019
Two new examples of cyanido-bridged {FeIIILnIII}2 molecular squares, with pyim and PPh3O as capping ligands at the LnIII sites, exhibit weak antiferromagnetic interactions [Ln = Eu (1), Sm (2), pyim = 2-(1H-imidazol-2-yl)pyridine, PPh3PO = triphenylphosphine oxide].
Further synthetic investigation of the general lanthanoid(iii) [Ln(iii)]/copper(ii)/pyridine-2,6-dimethanol/carboxylate reaction system: {CuII5LnIII4…
2021
In addition to previously studied {CuII3Gd6}, {CuII8Gd4}, {CuII15Ln7} and {CuII4Ln8} coordination clusters (Ln = trivalent lanthanide) containing pdm2− or Hpdm− ligands (H2pdm = pyridine-2,6-dimethanol) and ancillary carboxylate groups (RCO2−), the present work reports the synthesis and study of three new members of a fifth family of such complexes. Compounds [Cu5Ln4O2(OMe)4(NO3)4(O2CCH2But)2(pdm)4(MeOH)2] (Ln = Dy, 1; Ln = Tb, 2; Ln = Ho, 3) were prepared from the reaction of Ln(NO3)3·xH2O (x = 5, 6), CuX2·yH2O (X = ClO4, Cl, NO3; y = 6, 2 and 3, respectively), H2pdm, ButCH2CO2H and Et3N (2 : 2.5 : 2 : 1 : 9) in MeCN/MeOH. Rather surprisingly, the copper(II)/yttrium(III) analogue has a sli…
Synthesis, Structure, and Magnetic Properties of a Family of Heterometallic Pentanuclear [Co 4 Ln] (Ln = Gd III , Dy III , Tb III , and Ho III ) Asse…
2013
The reaction of 6-formyl-2-(hydroxymethyl)-4-methylphenol (LH2) with appropriate lanthanide salts followed by reaction with Co(OAc)2·4H2O afforded the pentanuclear heterobimetalllic compounds [Co4Ln(L)4(OAc)2(S)4](NO3)(S) [LnIII = GdIII, S = MeOH (1); LnIII = DyIII, S = H2O (2); LnIII = TbIII, S = MeOH (3); LnIII = HoIII, S = MeOH (4)] in good yields. All the compounds are stable in solution as confirmed by ESI-MS studies. These complexes contain a distorted Co4 tetrahedral core, which encapsulates a central lanthanide ion. The CoII and LnIII ions are in an all-oxygen environments. All the CoII ions possess a distorted octahedral geometry, and the LnIII ions are in a distorted square-antipr…
The crystal structure and magnetic properties of 3-pyridinecarboxylate-bridged Re(ii)M(ii) complexes (M = Cu, Ni, Co and Mn)
2015
The novel Re(II) complex NBu4[Re(NO)Br4(Hnic)] (1) and the heterodinuclear compounds [Re(NO)Br4(μ-nic)Ni(dmphen)2]·½CH3CN (2), [Re(NO)Br4(μ-nic)Co(dmphen)2]·½MeOH (3), [Re(NO)Br4(μ-nic)Mn(dmphen)(H2O)2]·dmphen (4), [Re(NO)Br4(μ-nic)Cu(bipy)2] (5) [Re(NO)Br4(μ-nic)Cu(dmphen)2] (5') (NBu4(+) = tetra-n-butylammonium cation, Hnic = 3-pyridinecarboxylic acid, dmphen = 2,9-dimethyl-1,10-phenanthroline, bipy = 2,2'-bipyridine) have been prepared and the structures of 1-5 determined using single crystal X-ray diffraction. The structure of 1 consists of [Re(NO)Br4(Hnic)](-) anions and NBu4(+) cations. Each Re(II) is six-coordinate with four bromide ligands, a linear nitrosyl group and a nitrogen ato…