Molecular Spin Clusters: New Synthetic Approaches and Neutron Scattering Studies

Basler, Reto; Boskovic, Colette; Chaboussant, Grégory; Güdel, Hans U.; Murrie, Mark; Ochsenbein, Stefan T.; Sieber, Andreas

doi:10.1002/cphc.200300689

Cited by 79 publications

(62 citation statements)

References 69 publications

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“…Perhaps most significantly, groups now routinely report field-dependent magnetisation alongside variable temperature susceptibility, and there is also now significant use of inelastic neutron scattering (INS), largely driven by Güdel in the first instance. 11 The number of parameters used in the spin Hamiltonian has also increased, primarily due to the realization that the anisotropy of the single ions is frequently of significance in determining physical behaviour. Recent work has also suggested that the form of the exchange interactions used is also vital, e.g.…”

Section: Introductionmentioning

confidence: 99%

On the Possibility of Magneto-Structural Correlations: Detailed Studies of Dinickel Carboxylate Complexes

Walsh

Sproules

Chilton³

et al. 2014

Inorg. Chem.

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Bu, L = HO 2 C t Bu (1), pyridine (2), 3-methylpyridine (4); L = L = pyridine (3), 3-methylpyridine (5)) has been synthesized and structurally characterized by X-ray crystallography. The magnetic properties have been probed by magnetometry and EPR spectroscopy, and detailed measurements show that the axial zero-field splitting, D, of the nickel( ) ions is on the same order as the isotropic exchange interaction, J, between the nickel sites. The isotropic exchange interaction can be related to the angle between the nickel centers and the bridging water molecule, while the magnitude of D can be related to the coordination sphere at the nickel sites.

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Section: Introductionmentioning

confidence: 99%

On the Possibility of Magneto-Structural Correlations: Detailed Studies of Dinickel Carboxylate Complexes

Walsh

Sproules

Chilton³

et al. 2014

Inorg. Chem.

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“…Most of the SMMs which have been synthesized so far are based on 3d metal ions, and several of them were studied by INS, but mostly for the transitions within the ground-state multiplet (for reviews see Basler et al, 2003;Bircher et al, 2006). However, being related to anisotropy and not the exchange splittings, these studies shall not be further discussed here; Fe 8 may serve as a representative example.…”

Section: A Introductionmentioning

confidence: 99%

Magnetic Cluster Excitations

Fürrer

2010

Int. J. Mod. Phys. B

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Magnetic clusters, i.e., assemblies of a finite number (between two or three and several hundred) of interacting spin centers which are magnetically decoupled from their environment, can be found in many materials ranging from inorganic compounds, magnetic molecules, artificial metal structures formed on surfaces to metalloproteins. The magnetic excitation spectra in them are determined by the nature of the spin centers, the nature of the magnetic interactions, and the particular arrangement of the mutual interaction paths between the spin centers. Small clusters of up to four magnetic ions are ideal model systems to examine the fundamental magnetic interactions which are usually dominated by Heisenberg exchange, but often complemented by anisotropic and/or higher-order interactions. In large magnetic clusters which may potentially deal with a dozen or more spin centers, the possibility of novel many-body quantum states and quantum phenomena are in focus. In this review the necessary theoretical concepts and experimental techniques to study the magnetic cluster excitations and the resulting characteristic magnetic properties are introduced, followed by examples of small clusters demonstrating the enormous amount of detailed physical information which can be retrieved. The current understanding of the excitations and their physical interpretation in the molecular nanomagnets which represent large magnetic clusters is then presented, with an own section devoted to the subclass of the singlemolecule magnets which are distinguished by displaying quantum tunneling of the magnetization. Finally, some quantum many-body states are summarized which evolve in magnetic insulators characterized by built-in or field-induced magnetic clusters. The review concludes addressing future perspectives in the field of magnetic cluster excitations.

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“…These can be used to calculate the INS intensity for a transition i!f, which is proportional to the scattering function S ab A C H T U N G T R E N N U N G (Q,w) given in Equation (2), [35] in which j,j' is the number of the Cr III centre; a and b stand for Cartesian coordinates x, y, z; Ŝ j,a is the a component of the spin operator Ŝ j at position r j ; j ii is the initial state of a transition with energy E i ; j fi the final state with energy E f ; p i is the Boltzmann population factor of state j ii and Q is the scattering vector or the momentum transfer between neutron and sample, respectively.…”

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confidence: 99%

Studies of Finite Molecular Chains: Synthesis, Structural, Magnetic and Inelastic Neutron Scattering Studies of Hexa‐ and Heptanuclear Chromium Horseshoes

Ochsenbein¹,

Tuna²,

Rancan³

et al. 2008

Chemistry A European J

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We report the synthesis and structural characterisation of a family of finite molecular chains, specifically [{[R(2)NH(2)](3)[Cr(6)F(11)(O(2)CCMe(3))(10)]}(2)] (in which R=nPr 1, Et 2, nBu 3), [{Et(2)NH}(2){[Et(2)NH(2)](3)[Cr(7)F(12)(O(2)CCMe(3))(12)][HO(2)CCMe(3)](2)}(2)] (4), [{[Me(2)NH(2)](3)[Cr(6)F(11)(O(2)CCMe(3))(10)]2.5 H(2)O}(4)] (5) and [{[iPr(2)NH(2)](3)[Cr(7)F(12)(O(2)CCMe(3))(12)]}(2)] (6). The structures all contain horseshoes of chromium centres, with each Cr...Cr contact within the horseshoe bridged by a fluoride and two pivalates. The horseshoes are linked through hydrogen bonds to the secondary ammonium cations in the structure, leading to di- and tetra-horseshoe structures. Through magnetic measurements and inelastic neutron scattering studies we have determined the exchange coupling constants in 1 and 6. In 1 it is possible to distinguish two exchange interactions, J(A)=-1.1 meV and J(B)=-1.4 meV; J(A) is the exchange interactions at the tips of the horseshoe and J(B) is the exchange within the body of the horseshoe (1 meV=8.066 cm(-1)). For 6 only one interaction was needed to model the data: J=-1.18 meV. The single-ion anisotropy parameters for Cr(III) were also derived for the two compounds as: for 1, D(Cr)=-0.028 meV and |E(Cr)|=0.005 meV; for 6, D(Cr)=-0.031 meV. Magnetic-field-dependent inelastic neutron scattering experiments on 1 allowed the Zeeman splitting of the first two excited states and level crossings to be observed. For the tetramer of horseshoes (5), quantum Monte Carlo calculations were used to fit the magnetic susceptibility behaviour, giving two exchange interactions within the horseshoe (-1.32 and -1.65 meV) and a weak inter-horseshoe coupling of +0.12 meV. Multi-frequency variable-temperature EPR studies on 1, 2 and 6 have also been performed, allowing further characterisation of the spin Hamiltonian parameters of these chains.

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Molecular Spin Clusters: New Synthetic Approaches and Neutron Scattering Studies

Cited by 79 publications

References 69 publications

On the Possibility of Magneto-Structural Correlations: Detailed Studies of Dinickel Carboxylate Complexes

On the Possibility of Magneto-Structural Correlations: Detailed Studies of Dinickel Carboxylate Complexes

Magnetic Cluster Excitations

Studies of Finite Molecular Chains: Synthesis, Structural, Magnetic and Inelastic Neutron Scattering Studies of Hexa‐ and Heptanuclear Chromium Horseshoes

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