Ferromagnetic alternating spin chains

Caneschi, Andrea; Gatteschi, Dante; Laugier, J; Rey, P.

doi:10.1021/ja00241a053

Cited by 154 publications

(75 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…From x-ray diffraction measurements [9], neighbor chains in Gd(hfac) 3 NITEt result in being well separated, as the minimum Gd-Gd distance is 10.5Å. Hence one can conclude [4,10] that the ratio between interchain and intrachain exchange interactions is negligible (≈10 −4 ). The rich low temperature phenomenology of this compound arises from the competition between the intrachain nn FM interaction (J z1 > 0) and the nnn AFM exchange interactions (J z2 < 0, J z2 < 0).…”

Section: Results In the Gadolinium Chainmentioning

confidence: 94%

“…In the last decades, it has been possible to synthesize organic molecules which incorporate magnetic ions and free radicals, resulting in quasi-one-dimensional (1D) magnetic chains with very interesting properties [1][2][3][4][5][6][7]. One of these new classes of compounds is characterized by the regular alternation of magnetic centers (M) and nitronyl-nitroxide organic radicals (NITR) along a certain crystallographic direction.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Proton NMR study of spin dynamics in the magnetic organic chainsM(hfac)3NITEt(M=Eu3+

et al. 2016

View full text Add to dashboard Cite

In this work, we present a nuclear magnetic resonance (NMR) study of the spin dynamics in the rare-earth-based low-dimensional molecular magnetic chains Eu(hfac) 3 NITEt and Gd(hfac) 3 NITEt (in short, Eu-Et and Gd-Et). Although both samples are based on the same chemical building block, [(hfac) 3 NITEt], their magnetic properties change dramatically when the Eu 3+ ion, which is nonmagnetic at low temperatures, is substituted by the magnetic Gd 3+ ion. The present proton NMR investigation shows that, down to the lowest investigated temperature (T = 1.5 K for Gd-Et and T = 3 K for Eu-Et), the Eu-Et chain behaves as a one-dimensional Heisenberg model with antiferromagnetic exchange coupling (J = −20 K) between s = 1/2 organic radicals, and has a T -independent exchange frequency (ω e = 2.6 × 10 12 rad/s). In the Gd-Et chain, in contrast, a competition arises between nearest-neighbor ferromagnetic coupling and next-nearest-neighbor antiferromagnetic coupling; moreover, two phase transitions have previously been found, in agreement with Villain's conjecture: a first transition, at T 0 = 2.2 K, from a high temperature paramagnetic phase to a chiral spin liquid phase, and a second transition, at T N = 1.9 K, to a three-dimensional helical spin solid phase. Contrary to the Eu-Et chain (whose three-dimensional ordering temperature is estimated to insurge at very low, T N ≈ 0.3 K), critical spin dynamics effects have been measured in the Gd-Et chain on approaching T N = 1.9 K: namely, a divergence of the proton nuclear spin-lattice relaxation rate 1/T 1 , which in turn produces a sudden wipe-out of the NMR signal in a very narrow ( T ∼ 0.04 K) temperature range above T N . Below T N , an inhomogeneous broadening of the NMR line indicates a complete spin freezing. At T 0 = 2.2 K, instead, such critical effects are not observed because NMR measurements probe the two-spin correlation function, while the chiral spin liquid phase transition is associated with a divergence of the four-spin correlation function.

show abstract

Section: Results In the Gadolinium Chainmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Proton NMR study of spin dynamics in the magnetic organic chainsM(hfac)3NITEt(M=Eu3+

et al. 2016

View full text Add to dashboard Cite

show abstract

“…For instance, the singlet-triplet energy gap in a dicopper(II) complex is given by Equation (3). (3) where K a,b is the bielectronic exchange integral,…”

Section: Theorymentioning

confidence: 99%

“…This topic started at the end of the eighties, aiming at obtaining magnets with interesting properties such as transparency or low density, which are also tunable by organic chemistry and easily synthesizable at low temperatures under soft chemistry conditions. [1][2][3] More recently, the discovery of Glauber's dynamics in 1D CPs [4] has renewed the interest in the synthesis of this type of compounds to obtain single-chain magnets (SCMs). For MBM or SCM systems, it is compulsory to gather a large number of strongly interacting magnetic centers.…”

Section: Introductionmentioning

confidence: 99%

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

et al. 2018

View full text Add to dashboard Cite

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.

show abstract

“…This bond angles are in good agreements with the previously reported. 6,9,17,26,32 Because one biradical has two radical unit, and the four coordination sites of this biradical are all employed to construct this one-dimensional chain, thus, not a simple one dimensional chain but a ladder-like structure ( Figure 5) consisting of two parallel alternating Cu-R-Cu-R chains is formed with the adjacent stairs distance of 8.023 Å. The shortest interchain Cu-Cu distance is 8.286 Å, while the Cu-Cu distance of two parallel alternating chains is 11.552 Å, which is longer than 7.864 Å, the shortest intra-chain Cu-Cu distance along the Cu-R-Cu-R chains.…”

Section: Crystal Structurementioning

confidence: 99%

A Ladder‐like One‐dimensional Chain Based on a New Biradical and Cu^II: Crystal Structure and Magnetic Properties

Wang

Yang

et al. 2010

Chin. J. Chem.

View full text Add to dashboard Cite

A new biradical di(4-(1'-oxyl-3'-oxido-4',4',5',5'-tetramethyl-4',5'-dihydro-1'H-imidazol-2'-yl)phenyl) ether (1) and its copper complex 2 were synthesized and characterized structurally. The X-ray structure determination revealed that, the complex is in the triclinic P-1 space group and displays a ladder-like structure. Each copper atom is surrounded by four oxygen atoms from hexafluoroacetylacetone and two oxygen atoms from biradical. The magnetic measurements show that biradical 1 exhibits a weak intramolecular nitroxide-nitroxide antiferromagnetic coupling and copper complex 2 possesses weak ferromagnetic coupling (J＝5.09 cm -1 ) between Cu II and radical, which attributed to interaction between copper spin and the axially coordinated nitronyl nitroxide spin.

show abstract

Ferromagnetic alternating spin chains

Cited by 154 publications

References 0 publications

Proton NMR study of spin dynamics in the magnetic organic chainsM(hfac)3NITEt(M=Eu3+

Proton NMR study of spin dynamics in the magnetic organic chainsM(hfac)3NITEt(M=Eu3+

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

A Ladder‐like One‐dimensional Chain Based on a New Biradical and Cu^II: Crystal Structure and Magnetic Properties

Contact Info

Product

Resources

About

Ferromagnetic alternating spin chains

Cited by 154 publications

References 0 publications

Proton NMR study of spin dynamics in the magnetic organic chainsM(hfac)3NITEt(M=Eu3+

Proton NMR study of spin dynamics in the magnetic organic chainsM(hfac)3NITEt(M=Eu3+

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

A Ladder‐like One‐dimensional Chain Based on a New Biradical and CuII: Crystal Structure and Magnetic Properties

Contact Info

Product

Resources

About

A Ladder‐like One‐dimensional Chain Based on a New Biradical and Cu^II: Crystal Structure and Magnetic Properties