Search results for "Magnetism"

On the magneto-structural role of the coordinating anion in oxamato-bridged copper(ii) derivatives

2019

We herein present the synthesis, spectroscopic analysis, description of the crystal structures and magnetic properties of four new complexes of the formula [{Cu(opba)(H2O)1.2}{Cu(dmphen)(SCN)}2]·dmf (1), [{Cu(opba)}2{Cu(dmphen)Cl}4]·1.5dmf·2.5dmso (2), [{Cu(opba)}2{Cu(dmphen)Br}4]·dmf·2.3dmso (3) and [{Cu(opba)}{Cu(dmphen)(dca)}2]n (4) [H4opba = N,N′-1,2-phenylenebis(oxamic acid), dmphen = 2,9-dimethyl-1,10-phenanthroline and dca = dicyanamide anion]. 1 is a neutral tricopper(II) complex where an inner [Cu(opba)]2− fragment adopts a bis-bidentate coordination mode towards two outer [Cu(dmphen)(NCS)]+ units. 2 and 3 are bis-trinuclear species where two oxamato-bridged [Cu(opba){Cu(dmphen)X}2…

Solid-State Molecular Nanomagnet Inclusion into a Magnetic Metal-Organic Framework: Interplay of the Magnetic Properties.

2015

Single-ion magnets (SIMs) are the smallest possible magnetic devices and are a controllable, bottom-up approach to nanoscale magnetism with potential applications in quantum computing and high-density information storage. In this work, we take advantage of the promising, but yet insufficiently explored, solid-state chemistry of metal-organic frameworks (MOFs) to report the single-crystal to single-crystal inclusion of such molecular nanomagnets within the pores of a magnetic MOF. The resulting host-guest supramolecular aggregate is used as a playground in the first in-depth study on the interplay between the internal magnetic field created by the long-range magnetic ordering of the structur…

A carboxylate-bridged NiII8 cluster with a distorted cubane topology: structure, magnetism and density functional studies

2016

Using a dicarboxylate ligand appended with (2-pyridyl)ethylamine unit, a new cluster [NiII8(L4)6(DMF)2(CH3OH)2(H2O)6][ClO4]4·2CH3OH·2CH3CO2C2H5 (1) [L4(2−): 3-[N-{2-(pyridin-2-yl)ethyl}amino]-bis(propionate)] has been synthesized, through ‘coordination-driven self-assembly’. The crystal structure of 1 reveals a centrosymmetric octanuclear carboxylate-bridged nickel(II) tetracation, with a distorted cubane topology. The four crystallographically independent nickel(II) centres differ markedly in their coordination environment. Magnetic studies (2–300 K) reveal that in 1 the net magnetic-exchange is antiferromagnetic. Based on geometric parameters associated with two interacting nickel(II) cen…

CuII2, CuII4 and CuII6 complexes with 3-(2-pyridyl)pyrazolate. Structure, magnetism and core interconversion

2019

Abstract Reactions of stoichiometric amounts of L1(−) (HL1 = 3-(2-pyridyl)pyrazole) with [Cu(H2O)6](ClO4)2, with or without PhCO2−, in MeOH or N,N′-dimethylformamide (dmf), led to the isolation of three copper(II) complexes of varying nuclearity, [CuII2(L1)2(ClO4)2(MeOH)2] (1), [CuII4(L1)4(O2CPh)2(MeOH)4](ClO4)2·2H2O (2) and [CuII6(L1)6(O2CPh)2(ClO4)2(dmf)4](ClO4)2·2dmf·2H2O (3). Structural analysis reveals two centrosymmetric four-coordinate {CuII(L1)(ClO4)(MeOH)} units are dipyrazolate-bridged in 1, giving rise to a square-pyramidal (SP; τ = 0.13) coordination to the CuII ion. In 2, two centrosymmetric four-coordinate dipyrazolate-bridged {CuII2(μ-L1)2(MeOH)2}2+ units in two layers are he…

Halide-Mediated Modification of Magnetism and Electronic Structure of α-Co(II) Hydroxides: Synthesis, Characterization, and DFT+U Simulations.

2019

The present study introduces a comprehensive exploration in terms of physicochemical characterization and calculations based on density functional theory with Hubbard's correction (DFT+U) of the whole family of α-Co(II) hydroxyhalide (F, Cl, Br, I). These samples were synthesized at room temperature by employing a one-pot approach based on the epoxide route. A thorough characterization (powder X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis/mass spectroscopy, and magnetic and conductivity measurements) corroborated by simulation is presented that analyzes the structural, magnetic, and electronic aspects. Beyond the inherent tendency of intercalated anions to …

2015

The energy barrier to magnetisation relaxation in single-molecule magnets (SMMs) proffers potential technological applications in high-density information storage and quantum computation. Leading candidates amongst complexes of 3d metals ions are the hexametallic family of complexes of formula [Mn6O2(R-sao)6(X)2(solvent)y] (saoH2=salicylaldoxime; X=mono-anion; y=4–6; R=H, Me, Et, and Ph). The recent synthesis of cationic [Mn6][ClO4]2 family members, in which the coordinating X ions were replaced with non-coordinating anions, opened the gateway to constructing families of novel [Mn6] salts in which the identity and nature of the charge balancing anions could be employed to alter the physical…

Magneto-structural correlations in a family of ReIVCuII chains based on the hexachlororhenate(IV) metalloligand

2017

Six novel one-dimensional chloro-bridged ReIVCuII complexes of formula {[Cu(L)4][ReCl6]}n, where L = imidazole (Imi, 1), 1-methylimidazole (Meim, 2), 1-vinylimidazole (Vim, 3), 1-butylimidazole (Buim, 4), 1-vinyl-1,2,4-triazole (Vtri, 5) and N,N’-dimethylformamide (DMF, 6) are characterised structurally, magnetically and theoretically. The structures exhibit significant differences in Cu–Cl bond lengths and Re–Cl–Cu bridging angles, resulting in large differences in the nature and magnitude of magnetic exchange interactions between the ReIV and CuII ions. Theoretical calculations reveal the coupling to be primarily ferromagnetic, increasing in magnitude as the bridging angle becomes smaller…

Magnetostructural correlations in CuII−NC−WV linkage: the case of [CuII(diimine)]2+−[WV(CN)8]3− 0D assemblies

2009

International audience; We report on the syntheses, crystal structures, and magnetic properties of two cyano-bridged molecular assemblies: [CuII(phen)3]2{[CuII(phen)2]2[WV(CN)8]2}(ClO4)2·10H2O (phen = 1,10-phenanthroline) (1) and {[CuII(bpy)2]2[WV(CN)8]} {[CuII(bpy)2][WV(CN)8]}·4H2O (bpy = 2,2′-bipyridyl) (2). Compound 1 consists of cyano-bridged [CuII2WV2]2− molecular rectangles and isolated [CuII(phen)3]2+ complexes. The molecular structure of 2 reveals cyano-bridged trinuclear [CuII2WV]+ and dinuclear [CuIIWV]− ions. Magnetic interactions in 1 are interpreted in terms of the model of a tetranuclear moiety consisting of two ferromagnetic CuII−NC−WV units (J1 = +39(4) cm−1) interacting ant…

Synthesis, crystal structure and magnetic properties of a cyanide-bridged heterometallic {CoIIMnIII} chain

2017

The assembly reaction between the low-spin [CoII(dmphen)(CN)3]- metalloligand and the [MnIII(salen)(H2O)]+ complex cation yielded the one-dimensional compound {[MnIII(salen)(μ-NC)2CoII(dmphen)(CN)]·2H2O}n (1), which behaves as a ferrimagnetic chain, the intrachain magnetic coupling being J = -1.71(1) cm-1.

Molecular materials based upon organic π-donors and magnetic anions

2000

Electrochemical combination of the magnetic dinuclear anion [MM'(C 2 O 4 )(NCS) 8 ] 4- (MM' = CrCr, CrFe) or paramagnetic mononuclear anion [Cr(NCS) 6 ] 3- with the ET organic π-donor (ET = BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene) gives rise to two new series of molecular hybrid salts formulated (ET) 5 [MM'(C 2 O 4 )(NCS) 8 (MM' = CrCr (1), CrFe (2)), (ET) 8 [MM'(C 2 O 4 )(NCS) 8 ] (3), (ET) 5.5 f Cr(NCS) 6 ] (4) and (ET) 5 [(C 2 H 5 ) 4 N] [Cr(NCS) 6 ](THF) (5) (THF = tetrahydrofuran). The crystal structures consist of alternating organic and inorganic layers. The organic part does not produce any detectable effect on the magnetic properties coming from the inorganic sublattice. T…