Raising the Spin-Reversal Barrier in Cyano-Bridged Single-Molecule Magnets: Linear MnIII2MIII(CN)6 (M = Cr, Fe) Species Incorporating [(5-Brsalen)Mn]+ Units

Choi, Hye Jin; Sokol, Jennifer J.; Long, Jeffrey R.

doi:10.1021/ic035327q

Cited by 230 publications

(137 citation statements)

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“…[17] Although, [(salen)Mn III ] + units are incorporated as a source of single-ion magnetic anisotropy, this heptanuclear complex does not behave as a SMM. [18] Trinuclear complexes of the tert-butyl triplesalen derivative H 6 talen tBu 2 (Scheme 2 a) are not flat but bowl-shaped (Scheme 2 b). [19] This ligand folding preorganizes the three metal ions for a facial coordination by three N donor atoms of a [M B (CN) 6 ] nÀ ion, thus favoring the formation of heptanuclear complexes M A 6 M B by molecular recognition in analogy to the lock-and-key principle (Scheme 2 c).…”

mentioning

confidence: 99%

Property‐Oriented Rational Design of Single‐Molecule Magnets: A C₃‐Symmetric Mn₆Cr Complex based on Three Molecular Building Blocks with a Spin Ground State of S_t=21/2

et al. 2006

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Single-molecule magnets (SMMs) are a class of coordination compounds that attract attention because of their magnetic bistability.[1] These finite-size molecules show a slow relaxation of the magnetization at low temperatures owing to an energy barrier for spin reversal resulting in a hysteresis of the magnetization which is of purely molecular origin. [2, 3] SMMs promise access to dynamic random access memory (RAM) devices for quantum computing and to ultimate high-density memory storage devices in which each bit of digital information might be stored on a single molecule.[4] The energy barrier (D S t ·S t 2 ) for spin reversal arises from the combination of a high spin ground state S t and a magnetic anisotropy of the easy-axis type (negative zero-field splitting parameter D S t ). [2,5] Since the discovery of the fascinating SMM behavior of Mn 12 , a lot of synthetic efforts have been devoted to the preparation of new molecules with an increased anisotropy barrier and impressive new structural motives have been reported. [6] The necessary requirements for SMMs are a high spin ground state S t and a strong magnetic anisotropy D S t . To rationally design polynuclear complexes with high spin ground states S t , a control of the exchange couplings is highly desirable. The main component of the magnetic anisotropy of the ground state (D S t ) usually comes from the projection of the single-site anisotropies (D i ) onto the spin ground state S t , while dipolar and anisotropic interactions yield only minor contributions. [7,8] Since zero-field splittings are tensor quantities, the projection of the single-site zerofield splittings onto the spin ground state may vanish when the metal-ion arrangement approaches a cubic symmetry. Thus, a rational design of SMMs requires a control of the molecular topology which can not be achieved by simply increasing the nuclearity of complexes and using small bridging ligands. Another prerequisite for a SMM to function as a data storage is the minimization of the quantum-mechanical magnetization tunneling which provides an alternative pathway for spinreversal and thus the loss of information. This tunneling mechanism is directly related to the rhombic component of the magnetic anisotropy expressed by E S t which is exactly zero for complexes with at least a threefold axis. Thus, there are several requirements for a targeted synthesis of SMMs which must be considered when designing a polynucleating ligand of low flexibility.We have designed the C 3 -symmetric triplesalen ligand C (Scheme 1) which combines the phloroglucinol bridging unit (A) with the coordination environment of a salen ligand (B). [9] In trinuclear Cu II [10] and Mo V [11] complexes the phloroglucinol bridging unit A acts as a ferromagnetic coupler by the spin-polarization mechanism. To introduce magnetic anisotropy we have been choosing a salen-like coordination environment B which causes a pronounced magnetic anisotropy through its strong ligand field in the basal plane. [8,12] A well documented example is t...

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Property‐Oriented Rational Design of Single‐Molecule Magnets: A C₃‐Symmetric Mn₆Cr Complex based on Three Molecular Building Blocks with a Spin Ground State of S_t=21/2

et al. 2006

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“…Indeed, at low temperatures the relaxation dynamics of SCMs are typically described by the finite-length model [11]. Cyano-bridged metal assemblies have provided a large number of compounds with SMM [31][32][33][34][35][36][37][38] and SCM behaviors [39][40][41][42][43][44][45][46][47][48]. The larger part of these materials comprise 3d metal ions as the core magnetic units.…”

Section: Introductionmentioning

confidence: 99%

Neutral Low-Dimensional Assemblies of a Mn(III) Schiff Base Complex and Octacyanotungstate(V): Synthesis, Characterization, and Magnetic Properties

et al. 2017

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Two novel low-dimensional molecular magnetic materials were prepared by the self-assembly of 3d-and 5d-metal complexes. These are the first neutral heterobimetallic cyanobridged compounds involving one anisotropic Mn(III) Schiff base complex and one octacyanotungstate(V) per molecular unit. A slow diffusion of the constituents' solutions leads to the formation of the 0D crystalline complex 1, due to coordination of a water molecule to the Mn center, which prevents polymer formation. A rapid mixing of reagents results in the precipitation of the microcrystalline powder of complex 2, which based on the totality of experimental data, possesses a 1D polymeric structure. The magnetic studies have shown that antiferromagnetic exchange interactions prevail in 1 (J/k B = −13.1(7) K, D = −3.0(1.3) K, zJ' = −0.16(20) K and g av = 2.00(1)); while the presence of the significant intramolecular Mn(III)-W(V) ferromagnetic coupling through cyanide bridge is characteristic for 2 (J/k B = 46.1(5) K, g Mn = 2.11(3), fixed g W = 2.0). Due to the weak interchain interactions, zJ /k B = −0.8(2) K, and compound 2 is a metamagnet with the Néel temperature of 9.5 K undergoing a spin-flip transition at 2 kOe. The slow magnetization dynamics of 2 were investigated at a DC field of 0 and 2 kOe, giving the values of τ 0 32(15) and 36(15) ps, respectively, well within the range typical for single-chain magnets (SCMs). The respective ∆ τ /k B values were 48.4(1.2) and 44.9(1.0) K.

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“…Cyano-bridged metal assemblies have provided a large number of compounds with SMM [31][32][33][34][35][36][37][38] and SCM behavior [39][40][41][42][43][44][45][46][47][48]. The greater part of these materials comprises 3d metal ions as the core magnetic units.…”

Section: Introductionmentioning

confidence: 99%

Neutral Low-Dimensional Assemblies of a Mn(III) Schiff Base Complex and Octacyanotungstate(V): Synthesis, Characterization and Magnetic Properties

Majcher

Pilet²,

Mironov³

et al. 2017

Preprint

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Two novel low-dimensional molecular magnetic materials were prepared by a self-assembling of 3d-and 5d-metal complexes. These are the first neutral heterobimetallic cyanobridged compounds involving one anisotropic Mn(III) Schiff base complex and one octacyanotungstate(V) per molecular unit. A slow diffusion of the constituents' solutions leads to a formation of the 0D crystalline complex 1 due to coordination of a water molecule to the Mn center prevents a polymer formation. A rapid mixing of reagents results in a precipitation of the microcrystalline powder of the complex 2, which on a totality of experimental data possess 1D polymeric structure. The magnetic studies have shown that antiferromagnetic exchange interactions are dominating in 1 J/kB= -13.1(7) K, D=-3.0(1.3) K, zJ'= -0.16(20) K and gav=2.00(1); while the presence of the significant intramolecular Mn(III)-W(V) ferromagnetic couplings through cyanide bridges is characteristic for 2 (J/kB = 46.1(5) K gMn = 2.11(3), fixed gW = 2.0). Due to the weak interchain interactions, zJ'/kB = -0.8(2) K, compound 2 is a metamagnet with the Néel temperature of 9.5 K undergoing a spin-flip transition at 2 kOe. The slow magnetization dynamics of 2 was investigated at DС field of 0 and 2 kOe, giving the values of τ0 32(15) and 36(15) ps respectively, well within the range typical for SCMs. The respective ∆τ/kB values were 48.4(1.2) and 44.9(1.0) K.

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Raising the Spin-Reversal Barrier in Cyano-Bridged Single-Molecule Magnets: Linear Mn^III₂M^III(CN)₆ (M = Cr, Fe) Species Incorporating [(5-Brsalen)Mn]⁺ Units

Cited by 230 publications

References 18 publications

Property‐Oriented Rational Design of Single‐Molecule Magnets: A C₃‐Symmetric Mn₆Cr Complex based on Three Molecular Building Blocks with a Spin Ground State of S_t=21/2

Property‐Oriented Rational Design of Single‐Molecule Magnets: A C₃‐Symmetric Mn₆Cr Complex based on Three Molecular Building Blocks with a Spin Ground State of S_t=21/2

Neutral Low-Dimensional Assemblies of a Mn(III) Schiff Base Complex and Octacyanotungstate(V): Synthesis, Characterization, and Magnetic Properties

Neutral Low-Dimensional Assemblies of a Mn(III) Schiff Base Complex and Octacyanotungstate(V): Synthesis, Characterization and Magnetic Properties

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Raising the Spin-Reversal Barrier in Cyano-Bridged Single-Molecule Magnets: Linear MnIII2MIII(CN)6 (M = Cr, Fe) Species Incorporating [(5-Brsalen)Mn]+ Units

Cited by 230 publications

References 18 publications

Property‐Oriented Rational Design of Single‐Molecule Magnets: A C3‐Symmetric Mn6Cr Complex based on Three Molecular Building Blocks with a Spin Ground State of St=21/2

Property‐Oriented Rational Design of Single‐Molecule Magnets: A C3‐Symmetric Mn6Cr Complex based on Three Molecular Building Blocks with a Spin Ground State of St=21/2

Neutral Low-Dimensional Assemblies of a Mn(III) Schiff Base Complex and Octacyanotungstate(V): Synthesis, Characterization, and Magnetic Properties

Neutral Low-Dimensional Assemblies of a Mn(III) Schiff Base Complex and Octacyanotungstate(V): Synthesis, Characterization and Magnetic Properties

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Raising the Spin-Reversal Barrier in Cyano-Bridged Single-Molecule Magnets: Linear Mn^III₂M^III(CN)₆ (M = Cr, Fe) Species Incorporating [(5-Brsalen)Mn]⁺ Units

Property‐Oriented Rational Design of Single‐Molecule Magnets: A C₃‐Symmetric Mn₆Cr Complex based on Three Molecular Building Blocks with a Spin Ground State of S_t=21/2

Property‐Oriented Rational Design of Single‐Molecule Magnets: A C₃‐Symmetric Mn₆Cr Complex based on Three Molecular Building Blocks with a Spin Ground State of S_t=21/2