Single-molecule magnets: control by a single solvent molecule of Jahn–Teller isomerism in [Mn12O12(O2CCH2But)16(H2O)4]

2003 ◽  
pp. 2672-2673 ◽  
Author(s):  
Mònica Soler ◽  
Wolfgang Wernsdorfer ◽  
Ziming Sun ◽  
John C. Huffman ◽  
David N. Hendrickson ◽  
...  
Keyword(s):  
Single Molecule ◽  
Solvent Molecule ◽  
Single Molecule Magnets ◽  
Jahn Teller

scholarly journals Vibrational Coherences in Manganese Single-molecule Magnets after Ultrafast Photoexcitation

2018 ◽  
Author(s):  
Florian Liedy ◽  
Robbie McNab ◽  
Julien Eng ◽  
Ross Inglis ◽  
Thomas Penfold ◽  
...  
Keyword(s):  
Data Storage ◽  
Single Molecule ◽  
Optical Data Storage ◽  
Transient Absorption Spectroscopy ◽  
Optical Data ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Single Molecule Magnets ◽  
Teller Distortion ◽  
Jahn Teller

<p>Single-Molecule Magnets (SMMs) are metal complexes with two degenerate magnetic ground states arising from a non-zero spin ground state and a zero-field splitting. SMMs are promising for future applications in data storage, however, to date the ability to manipulate the spins using optical stimulus is lacking. Here, we have explored the ultrafast dynamics occurring after photoexcitation of two structurally related Mn(III)-based SMMs, whose magnetic anisotropy is closely related to the Jahn-Teller distortion, and demonstrate coherent modulation of the axial anisotropy on a femtosecond timescale. Ultrafast transient absorption spectroscopy in solution reveals oscillations superimposed on the decay traces with corresponding energies around 200 cm<sup>−1</sup>, coinciding with a vibrational mode along the Jahn-Teller axis. Our results provide a non-thermal, coherent mechanism to dynamically control the magnetisation in SMMs and open up new molecular design challenges to enhance the change in anisotropy in the excited state, which is essential for future ultrafast magneto-optical data storage devices.</p>

Mixed valency in polynuclear Mn II /Mn III , Mn III /Mn IV and Mn II /Mn III /Mn IV clusters: a foundation for high-spin molecules and single-molecule magnets

2007 ◽  
Vol 366 (1862) ◽  
pp. 113-125 ◽  
Author(s):  
Theocharis C Stamatatos ◽  
George Christou
Keyword(s):  
Single Molecule ◽  
Exchange Interactions ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Single Molecule Magnets ◽  
Zero Field Splitting Parameter ◽  
Jahn Teller ◽  
Splitting Parameter ◽  
Molecular Spin ◽  
Molecular Compounds

Mixed-valent Mn/O dinuclear and polynuclear molecular compounds containing Mn III are almost without exception trapped valence. Large differences between the strengths of the exchange interactions within Mn II Mn III , Mn III Mn III and Mn III Mn IV pairs lead to situations where Mn III Mn IV interactions, the strongest of the three mentioned and antiferromagnetic in nature, dominate the intramolecular spin alignments in trinuclear and higher nuclearity mixed-valent complexes and often result in molecules that have large, and sometimes abnormally large, values of molecular spin ( S ). When coupled to a large molecular magnetoanisotropy of the easy-axis-type (negative zero-field splitting parameter, D ), also primarily resulting from individual Jahn–Teller distorted Mn III centres, such molecules will function as single-molecule magnets (molecular nanomagnets). Dissection of the structures and exchange interactions within a variety of mixed-valent Mn x cluster molecules with metal nuclearities of Mn 4 , Mn 12 and Mn 25 allows a ready rationalization of the observed S , D and overall magnetic properties in terms of competing antiferromagnetic exchange interactions within triangular subunits, resulting spin alignments and relative orientation of Mn III JT axes. Such an understanding has provided a stepping stone to the identification of a ‘magnetically soft’ Mn 25 cluster whose groundstate spin S value can be significantly altered by relatively minor structural perturbations. Such ‘spin tweaking’ has allowed this cluster to be obtained in three different forms with three different groundstate S values.

scholarly journals Asymmetric Dinuclear Lanthanide(III) Complexes from the Use of a Ligand Derived from 2-Acetylpyridine and Picolinoylhydrazide: Synthetic, Structural and Magnetic Studies

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3153
Author(s):  
Diamantoula Maniaki ◽  
Panagiota S. Perlepe ◽  
Evangelos Pilichos ◽  
Sotirios Christodoulou ◽  
Mathieu Rouzières ◽  
...  
Keyword(s):  
Single Molecule ◽  
Metal Ion ◽  
Ac Susceptibility ◽  
Solvent Molecule ◽  
Exchange Interactions ◽  
Experimental Fact ◽  
Anisotropy Axis ◽  
Magnetic Studies ◽  
Single Molecule Magnets ◽  
Magnetization Relaxation

A family of four Ln(III) complexes has been synthesized with the general formula [Ln2(NO3)4(L)2(S)] (Ln = Gd, Tb, Er, and S = H2O; 1, 2 and 4, respectively/Ln = Dy, S = MeOH, complex 3), where HL is the flexible ditopic ligand N’-(1-(pyridin-2-yl)ethylidene)pyridine-2-carbohydrazide. The structures of isostructural MeOH/H2O solvates of these complexes were determined by single-crystal X-ray diffraction. The two LnIII ions are doubly bridged by the deprotonated oxygen atoms of two “head-to-head” 2.21011 (Harris notation) L¯ ligands, forming a central, nearly rhombic {LnIII2(μ-OR)2}4+ core. Two bidentate chelating nitrato groups complete a sphenocoronal 10-coordination at one metal ion, while two bidentate chelating nitrato groups and one solvent molecule (H2O or MeOH) complete a spherical capped square antiprismatic 9-coordination at the other. The structures are critically compared with those of other, previously reported metal complexes of HL or L¯. The IR spectra of 1–4 are discussed in terms of the coordination modes of the organic and inorganic ligands involved. The f-f transitions in the solid-state (diffuse reflectance) spectra of the Tb(III), Dy(III), and Er(III) complexes have been fully assigned in the UV/Vis and near-IR regions. Magnetic susceptibility studies in the 1.85–300 K range reveal the presence of weak, intramolecular GdIII∙∙∙GdIII antiferromagnetic exchange interactions in 1 [J/kB = −0.020(6) K based on the spin Hamiltonian Ĥ = −2J(ŜGd1∙ ŜGd2)] and probably weak antiferromagnetic LnIII∙∙∙LnIII exchange interactions in 2–4. Ac susceptibility measurements in zero dc field do not show frequency dependent out-of-phase signals, and this experimental fact is discussed for 3 in terms of the magnetic anisotropy axis for each DyIII center and the oblate electron density of this metal ion. Complexes 3 and 4 are Single-Molecule Magnets (SMMs) and this behavior is optimally observed under external dc fields of 600 and 1000 Oe, respectively. The magnetization relaxation pathways are discussed and a satisfactory fit of the temperature and field dependencies of the relaxation time τ was achieved considering a model that employs Raman, direct, and Orbach relaxation mechanisms.

scholarly journals Single-molecule magnets: Jahn–Teller isomerism and the origin of two magnetization relaxation processes in Mn12 complexes

Polyhedron ◽  
2001 ◽  
Vol 20 (11-14) ◽  
pp. 1139-1145 ◽  
Author(s):  
Sheila M.J Aubin ◽  
Ziming Sun ◽  
Hilary J Eppley ◽  
Evan M Rumberger ◽  
Ilia A Guzei ◽  
...  
Keyword(s):  
Single Molecule ◽  
Relaxation Processes ◽  
Single Molecule Magnets ◽  
Magnetization Relaxation ◽  
Jahn Teller

The origin of the second relaxation process in the [Mn12O12(O2CR)16(H2O)4] single-molecule magnets: ‘Jahn–Teller isomerism’ in the [Mn12O12] core

1999 ◽  
pp. 1973-1974 ◽  
Author(s):  
Ziming Sun ◽  
Daniel Ruiz ◽  
David N. Hendrickson ◽  
Neil R. Dilley ◽  
M. Brian Maple ◽  
...  
Keyword(s):  
Relaxation Process ◽  
Single Molecule ◽  
Single Molecule Magnets ◽  
Jahn Teller

scholarly journals Vibrational Coherences in Manganese Single-molecule Magnets after Ultrafast Photoexcitation

2018 ◽  
Author(s):  
Florian Liedy ◽  
Robbie McNab ◽  
Julien Eng ◽  
Ross Inglis ◽  
Thomas Penfold ◽  
...  
Keyword(s):  
Data Storage ◽  
Single Molecule ◽  
Optical Data Storage ◽  
Transient Absorption Spectroscopy ◽  
Optical Data ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Single Molecule Magnets ◽  
Teller Distortion ◽  
Jahn Teller

<p>Single-Molecule Magnets (SMMs) are metal complexes with two degenerate magnetic ground states arising from a non-zero spin ground state and a zero-field splitting. SMMs are promising for future applications in data storage, however, to date the ability to manipulate the spins using optical stimulus is lacking. Here, we have explored the ultrafast dynamics occurring after photoexcitation of two structurally related Mn(III)-based SMMs, whose magnetic anisotropy is closely related to the Jahn-Teller distortion, and demonstrate coherent modulation of the axial anisotropy on a femtosecond timescale. Ultrafast transient absorption spectroscopy in solution reveals oscillations superimposed on the decay traces with corresponding energies around 200 cm<sup>−1</sup>, coinciding with a vibrational mode along the Jahn-Teller axis. Our results provide a non-thermal, coherent mechanism to dynamically control the magnetisation in SMMs and open up new molecular design challenges to enhance the change in anisotropy in the excited state, which is essential for future ultrafast magneto-optical data storage devices.</p>

scholarly journals Single-Molecule Magnets:  Ligand-Induced Core Distortion and Multiple Jahn−Teller Isomerism in [Mn12O12(O2CMe)8(O2PPh2)8(H2O)4]

2001 ◽  
Vol 123 (40) ◽  
pp. 9914-9915 ◽  
Author(s):  
Colette Boskovic ◽  
Maren Pink ◽  
John C. Huffman ◽  
David N. Hendrickson ◽  
George Christou
Keyword(s):  
Single Molecule ◽  
Single Molecule Magnets ◽  
Jahn Teller

scholarly journals Single-Molecule Magnets:  Jahn−Teller Isomerism and the Origin of Two Magnetization Relaxation Processes in Mn12Complexes

2001 ◽  
Vol 40 (9) ◽  
pp. 2127-2146 ◽  
Author(s):  
Sheila M. J. Aubin ◽  
Ziming Sun ◽  
Hilary J. Eppley ◽  
Evan M. Rumberger ◽  
Ilia A. Guzei ◽  
...  
Keyword(s):  
Single Molecule ◽  
Relaxation Processes ◽  
Single Molecule Magnets ◽  
Magnetization Relaxation ◽  
Jahn Teller

Seeking Magneto-Structural Correlations in Easily Tailored Pentagonal Bipyramid Dy(III) Single-Ion Magnets

2019 ◽  
Author(s):  
Guo-Zhang Huang ◽  
Ze-Yu Ruan ◽  
Jie-Yu Zheng ◽  
Yan-Cong Chen ◽  
Si-Guo Wu ◽  
...  
Keyword(s):  
Single Molecule ◽  
Structural Engineering ◽  
Magnetic Hysteresis ◽  
Sweep Rate ◽  
Coordination Bond ◽  
Pentagonal Bipyramid ◽  
Single Molecule Magnets ◽  
Crystal Field Theory ◽  
Bond Angles ◽  
Axial Coordination

<p><a></a>Controlling molecular magnetic anisotropy via structural engineering is delicate and fascinating, especially for single-molecule magnets (SMMs). Herein a family of dysprosium single-ion magnets (SIMs) sitting in pentagonal bipyramid geometry have been synthesized with the variable-size terminal ligands and counter anions, through which the subtle coordination geometry of Dy(III) can be finely tuned based on the size effect. The effective energy barrier (Ueff) successfully increases from 439 K to 632 K and the magnetic hysteresis temperature (under a 200 Oe/s sweep rate) raises from 11 K to 24 K. Based on the crystal-field theory, a semi-quantitative magneto-structural correlation deducing experimentally for the first time is revealed that the Ueff is linearly proportional to the structural-related value S2<sup>0</sup> corresponding to the axial coordination bond lengths and the bond angles. Through the evaluation of the remanent magnetization from hysteresis, quantum tunneling of magnetization (QTM) is found to exhibit negative correlation with the structural-related value S<sub>tun</sub> corresponding to the axial coordination bond angles.<br></p>

Sign in / Sign up

Export Citation Format

Share Document