Cobalt(<scp>II</scp>)–Copper(<scp>II</scp>) Bimetallic Chains as a New Class of Single‐Chain Magnets

Pardo, Emilio; Ruiz-Garcı́a, Rafael; Lloret, Francesc; Faus, Juan; Julve, Miguel; Journaux, Yves; Delgado, Fernando; Ruiz-Perez, Catalina

doi:10.1002/adma.200400253

Cited by 138 publications

(62 citation statements)

References 13 publications

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“…[3,22,23] We used the Arrhenius equation t = t 0 expA C H T U N G T R E N N U N G (D/kT), in which t = 1/2pf, to obtain parameters pertinent to a magnetic relaxation process. As seen in Figure 5, a least-squares fit of the cusp temperatures in the c m '' curves to the equation yields t 0 = 4.16 10 À11 s and D/k = 39.1 K. The obtained pre-exponential factor concurs with observed values for SCMs, [3][4][5][6][7][8] and the average energy barrier for the reversal of the magnetization is comparable to that for the phosphinate-bridged Mn III complex.…”

supporting

confidence: 82%

“…The data were fit with a generalized Debye model, [24] leading to values of a equal to 0.24 at 2.8 K and 0.23 at 3.1 K. The a values suggest a narrow distribution of relaxation times, which is consistent with reported SCMs. [3][4][5][6][7][8]25] It is worth noting that the c m '' signals totally vanish at a magnetic field of 6 T (Figure 4). This salient feature is in concert with the disappearance of spin canting at the same field, as shown in Figure S6 in the Supporting Information.…”

mentioning

confidence: 99%

“…In the pursuit of such anisotropic chains, much effort has been directed to generate ferromagnetically coupled spins and eventually facilitate Ising-type magnetic anisotropy on a chain according to Glauber theory. [2] A good number of SCMs have been characterized structurally and magnetically and they include 3d, [3] 3d-radical, [4] 3d-3d, [5] 3d-5d, [6] 3d-4f, [7] and 4f-radical systems. [8] The strategies used frequently are to devise one-dimensional (1D) chains with ferromagnetic or ferrimangetic coupling.…”

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confidence: 99%

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An End‐On Azide‐Bridged Antiferromagnetic Single‐Chain Magnet Involving Spin Canting and Field‐Induced Two‐Step Magnetic Transitions

Yoon

Ryu

Kim

et al. 2009

Chemistry A European J

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The preparation and dynamic behavior of two functionally rigid and degenerate [2]rotaxanes (14 PF(6) and 24 PF(6)) in which a pi-electron deficient tetracationic cyclophane, cyclobis(paraquat-p-phenylene) (CBPQT(4+)) ring, shuttles back and forth between two pi-electron-rich naphthalene (NP) stations by making the passage along an ethynyl-phenylene-(PH)-ethynyl or butadiyne rod, are described. The [2]rotaxanes were synthesized by using the clipping approach to template-directed synthesis, and were characterized by NMR spectroscopic and mass spectrometric analyses. (1)H NMR spectra of both [2]rotaxanes show evidence for the formation of mechanically interlocked structures, resulting in the upfield shifts of the resonances for key protons on the dumbbell-shaped components. In particular, the signals for the peri protons on the NP units in the dumbbell-shaped components experienced significant upfield shifts at low temperatures, just as has been observed in the flexible [2]rotaxanes. Interestingly, the resonances for the same protons did not exhibit a significant upfield shift at 298 K, but rather only a modest shift. This phenomenon arises from the much reduced binding of the ethynyl-NP unit compared to the 1,5-dioxy-NP unit. This effect, in turn, increases the shuttling rate when compared to the 1,5-dioxy-NP-based rotaxane systems investigated previously. The kinetic and thermodynamic data of the shuttling behavior of the CBPQT(4+) ring between the NP units were obtained by variable-temperature NMR spectroscopy and using the coalescence method to calculate the free energies of activation (DeltaG(c) ( not equal)) of 9.6 and 10.3 kcal mol(-1) for 14 PF(6) and 24 PF(6), respectively, probed by using the rotaxane's alpha-bipyridinium protons. The solid-state structure of the free dumbbell-shaped compound (3) shows the fully rigid ethynyl-PH-ethynyl linker with a length (8.1 A) twice as long as that (3.8 A) of the butadiyne linker. Full-atomistic simulations were carried out with the DREIDING force field (FF) to probe the degenerate molecular shuttling processes, and afforded shuttling energy barriers (DeltaG( not equal)=10.4 kcal mol(-1) for 14 PF(6) and 24 PF(6)) that are in good agreement with the experimental values (DeltaG(c) ( not equal)=9.6 and 10.3 kcal mol(-1) for 14 PF(6) and 24 PF(6), respectively, probed by using their alpha-bipyridinium protons).

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supporting

confidence: 82%

mentioning

confidence: 99%

mentioning

confidence: 99%

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An End‐On Azide‐Bridged Antiferromagnetic Single‐Chain Magnet Involving Spin Canting and Field‐Induced Two‐Step Magnetic Transitions

Yoon

Ryu

Kim

et al. 2009

Chemistry A European J

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“…[56,57] The X-ray structures of two of these Cu II Co II 1D systems were solved, namely [CoCu(Me 2 pma) 2 2 O} n (1D-CoCu-Me 3 pma). Both compounds consist of neutral oxamato-bridged cobalt(II)-copper(II) chains.…”

Section: Single-chain Magnets (Scms)mentioning

confidence: 99%

Design of Magnetic Coordination Polymers Built from Polyoxalamide Ligands: A Thirty Year Story

et al. 2018

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Abstract:The aim of this review is to pay tribute to the legacy of O. Kahn. Kahn's credo was to synthesize magnetic compounds with predictable structure and magnetic properties. This is illustrated herein with results obtained by Kahn's group during his Orsay period thirty years ago, but also on the basis of our recent results on the synthesis of coordination polymers with oxamate ligands. The first part of this review is devoted to a short description of the necessary knowledge in physics and theoretical chemistry that Kahn and his group have used to select oxamate ligands, the complex-as-ligand strategy and the synthesis of heterobimetallic systems. Then, we describe the strategies we have later used to obtain the desired target compounds. The use of complexes as building-blocks, associated to a control of the metal ions chirality and stoichiometry, allowed us to obtain coordination polymers with predictable dimensionality. For the synthesis of single-chain magnets (SCMs) we show IncipitFor this thematic issue dedicated to the attractive legacy of Olivier Kahn, we decided to write this paper on magnetic coordination polymers built from polyoxalamide ligands. Some of the authors of this paper were part of the exciting adventure at the time of the creation of the Kahn's group at the University of Paris-Sud. Kahn's credo was to synthesize magnetic compounds with predictable structure and magnetic properties and in order to achieve this goal one needs some backgrounds in physics, theory and synthetic chemistry. We have therefore tried that the ligand chemical flexibility makes the isolation of the chains in the solid and the occurence of slow magnetic relaxation possible. For 1D and 2D molecule-based magnets (MBMs), the magnetic ordering strongly depends on the interchain or interplane interactions, which are difficult to control. Again the flexibility of the oxamate ligands allowed their strengthening in the solid sate, yielding MBMs with critical temperatures up to 30 K. We will also present our results on 3D coordination polymers, particularly on the porous magnets displaying large octagonal channels. This family of porous MBMs possess outstanding chemical properties, such as post-synthetic transformation in the solid state. Finally, we will also show that oxamate ligands allows the design of multifunctional materials, as in the case of the first chiral SCM. Overall, the results presented in this review show the impressive potential the oxamate ligands have for the design of coordination polymers.throughout this contribution to describe the historical process and the approach of the group's behind the choice of oxamate and oxamidate ligands to synthesize heterometallic coordination polymers.

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“…[13][14][15][16][17] Slow relaxation of the magnetization in a ferromagnetic Ising chain was first predicted by Glauber in 1965 and, after his theory, 18 the conditions to be fulfilled by a chain compound to be a SCM are: (i) the system must behave as a 1D Ising ferro-or ferrimagnet and (ii) the chains have to be well isolated from each other in order to hamper the transition to 3D magnetic ordering. Since this prediction, several families of SCMs have been prepared and magnetostructurally investigated, the bridging ligands being organic radicals, 17 single oximato/double phenoxo, 19 cyanido, 20 azido, 21 oxalato, 22 oxamato, 23 bis(2-pyridylcarbonyl) amidato, 24 carboxylato 25 and phosphato/phosphinato. 26 In an attempt to create SCMs working at high temperatures, we decided to take advantage of the strong magnetic coupling across the bis-dioximato bridge to design heterobimetallic Cu II -Mn III chains where the anisotropy would be ensured by the presence of the manganese(III) ion.…”

Section: Introductionmentioning

confidence: 99%

Slow relaxation of the magnetization in Oximato-bridged heterobimetallic Copper(II)-Manganese(III) chains

Ruiz

Castro

Pardo

et al. 2011

J. Braz. Chem. Soc.

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(3), com oxidação do íon manganês(II) a manganês(III) na presença de ar. Na ausência de monocristais para análise por difratometria de raios X, técnicas de absorção de raios X (EXAFS e XANES) foram usadas a 40 K para caracterização estrutural de 1-3. A análise dos dados de absorção de raios X revelou que 1-3 apresentam cadeias bimetálicas de íons Cu II e Mn III ligados por pontes oximato, em ambiente octaédrico (CuN 4 O 2 e MnO 6 ) alongado. Os estudos de propriedades magnéticas de 1-3 revelaram um comportamento metamagnético devido à coexistência de acoplamentos ferromagnéticos intracadeias fortes [J = +52.5 (1), +49.1 (2) e +52.1 cm -1 (3)] e interações antiferromagnéticas intercadeias fracas [j = −0.070 (1), −0.075 (2) e −0.078 cm -1 (3)]. A ortogonalidade estrita entre o orbital magnético do cobre(II) e aquele do centro magnético de manganês(III), junto com a conhecida habilidade do grupo oximato em mediar interações magnéticas quando atua como ponte entre dois íons metálicos, é responsável pela forte interação ferromagnética intracadeia em 1-3. Medidas de susceptibilidade sob corrente alternada realizadas para 1-3 em temperatura baixa e sob campo magnético dc igual a zero revelaram uma dependência do sinal ac fora de fase com a frequência do campo oscilante, como esperado para magnetos do tipo single-chain.The use of the oximato-containing copper(II) complexes, [Cu(Hdeg) (3) where the starting manganese(II) ion was oxidized to manganese(III) by air. In the lack of single crystals suitable for X-ray diffraction analysis, X-ray absorption techniques (EXAFS and XANES) at 40 K were used for the structural characterization of 1-3. The analysis of the X-ray absorption data reveals that 1-3 are oximato-bridged Cu II -Mn III bimetallic chains with elongated octahedral CuN 4 O 2 and MnO 6 surroundings. The study of the magnetic properties of 1-3 reveals a metamagnetic-like behavior due to the coexistence of strong intrachain ferromagnetic couplings [J = +52.5 (1), +49.1 (2) and +52.1 cm -1 (3)] and weak interchain antiferromagnetic interactions [j = −0.070 (1), −0.075 (2) and −0.078 cm -1 (3)]. The strict orthogonality between the magnetic orbital of the copper(II) ion and those of the manganese(III) center, together with the well known ability of the oximato group to mediate magnetic interactions when acting as a bridge between two metal ions, account for the relatively strong intrachain ferromagnetic coupling in 1-3. Alternating current susceptibility measurements for 1-3 in the low temperature range under zero dc magnetic field reveal a frequency-dependence of the out-of-phase ac signal as expected for single chain magnets.Keywords: metal oximates, heterobimetallic complexes, complex as ligand strategy, exchange coupling, single chain magnets Ruiz et al. 977 Vol. 22, No. 5, 2011 IntroductionSince the first report concerning the use of the dimethylglyoxime (H 2 dmg) as a reagent for nickel(II), 1 oximes as ligands have been widely used in coordination chemistry. Although the primary attention on them wa...

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Cobalt(II)–Copper(II) Bimetallic Chains as a New Class of Single‐Chain Magnets

Cited by 138 publications

References 13 publications

An End‐On Azide‐Bridged Antiferromagnetic Single‐Chain Magnet Involving Spin Canting and Field‐Induced Two‐Step Magnetic Transitions

An End‐On Azide‐Bridged Antiferromagnetic Single‐Chain Magnet Involving Spin Canting and Field‐Induced Two‐Step Magnetic Transitions

Design of Magnetic Coordination Polymers Built from Polyoxalamide Ligands: A Thirty Year Story

Slow relaxation of the magnetization in Oximato-bridged heterobimetallic Copper(II)-Manganese(III) chains

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