Mechanism of a Strongly Anisotropic MoIII−CN−MnIISpin−Spin Coupling in Molecular Magnets Based on the [Mo(CN)7]4-Heptacyanometalate:  A New Strategy for Single-Molecule Magnets with High Blocking Temperatures

In the basic and applied research, the electronics and spin degrees of freedom is a very promising field of research and development over the past decade, spintronics from fundamental physics to technical devices already have a great deal of progress. This study made an overview of the synthesis, structure and properties of single molecular magnets and their applications in molecular spin combined with the latest research on this study sphere. Single molecular magnets are made of inner magnetic nuclei and peripheral organic molecule lamella, which can improve physical and chemical properties by means of adorn radical of organic ligand and exchange internal magnetic ions. And this paper also analyzes the molecular spin of the electron spin and charge electronic devices at the molecular level.

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Ferromagnetic [Mn3] Single-Molecule Magnets and Their Supramolecular Networks

Australian Journal of Chemistry ◽

10.1071/ch09236 ◽

2009 ◽

Vol 62 (9) ◽

pp. 1108 ◽

Cited By ~ 22

Author(s):

Ross Inglis ◽

Giannis S. Papaefstathiou ◽

Wolfgang Wernsdorfer ◽

Euan K. Brechin

Keyword(s):

Single Molecule ◽

Quantum Physics ◽

Three Dimensional ◽

Exchange Interactions ◽

Molecular Magnets ◽

Single Molecule Magnets ◽

Spin Networks ◽

Quantum Tunnelling ◽

Field Bias ◽

Supramolecular Networks

The complexes [MnIII3O(Et-sao)3(O2CPh(Cl)2)(MeOH)3(H2O)] (1), [MnIII3O(Et-sao)3(ClO4)(MeOH)3] (2), [MnIII3O(Et-sao)3(O2Ph(CF3)2)(EtOH)(H2O)3] (3), and [MnIII3O(Ph-sao)3(O2C-anthra)(MeOH)4]·Ph-saoH2 (4·Ph-saoH2) display dominant ferromagnetic exchange interactions leading to molecules with S = 6 ground states. The molecules are single molecule magnets (SMM) displaying large effective energy barriers for magnetization reversal. In each case their crystal structures reveal multiple intermolecular H-bonding interactions. Single crystal hysteresis loop measurements demonstrate that these interactions are strong enough to cause a clear field bias, but too weak to transform the spin networks into classical antiferromagnets. These three-dimensional networks of exchange coupled SMMs demonstrate that quantum tunnelling magnetization can be controlled using exchange interactions, suggesting supramolecular chemistry can be exploited to modulate the quantum physics of molecular magnets.

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Dalton technical issue “Lanthanide and transition metal complexes as molecular magnets Single-molecule magnets within polyoxometalate-based frameworks

Dalton Transactions ◽

10.1039/d1dt01708j ◽

2021 ◽

Author(s):

Malihe Babaei Zarch ◽

Masoud Mirzaei ◽

Maryam Bazargan ◽

Sandeep K Gupta ◽

Franc Meyer ◽

...

Keyword(s):

Transition Metal ◽

Metal Complexes ◽

Transition Metal Complexes ◽

Single Molecule ◽

Molecular Magnets ◽

Technical Issue ◽

Hydrothermal Conditions ◽

Single Molecule Magnets ◽

Design And Synthesis

As an extension of our interest in polyoxometalates (POMs) and lanthanoids, we report the design and synthesis of two polyoxometalate-based frameworks under hydrothermal conditions; [Ho4(PDA)4(H2O)11][(SiO4)@W12O36]·8H2O (1) and [Tb4(PDA)4(H2O)12][(SiO4)@W12O36]·4H2O (2) (H2PDA...

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The Separation of the Mn12 Single-Molecule Magnets onto Spherical Silica Nanoparticles

Nanomaterials ◽

10.3390/nano9050764 ◽

2019 ◽

Vol 9 (5) ◽

pp. 764 ◽

Cited By ~ 6

Author(s):

Lukasz Laskowski ◽

Iwan Kityk ◽

Piotr Konieczny ◽

Oleksandr Pastukh ◽

Mateusz Schabikowski ◽

...

Keyword(s):

Single Molecule ◽

Molecular Magnets ◽

Single Molecule Magnets ◽

Silica Substrate ◽

Transmission Electron ◽

Spherical Silica ◽

The Individual ◽

Magnetic States ◽

First Time ◽

Direct Microscopic Observation

The Mn12 single-molecule magnets (SMMs) could be attached to the surface of spherical silica for the first time with a high probability. This allowed separation of the individual molecular magnets and direct microscopic observation of the SMMs. We described in detail how to fabricate such a composite material. The synthesis procedure proposed here is simple and efficient. We confirmed the efficiency of the method by transmission electron microscopy (TEM): single-molecule magnets were visible at the surface of a silica substrate. Based on TEM observation, we described how the molecules anchor to the surface of silica (the geometry of the magnetic molecule in regard to the surface of the substrate). The SQUID magnetometry showed that single-molecule magnet behaviour is kept intact after grafting. The attachment of the single-molecule magnets to the surface of silica allows to investigate their properties as separate molecules. This is particularly important in the analysis of magnetic properties such as magnetic states of the separated SMMs, their mutual interactions, and the influence of a silica support.

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

10.26434/chemrxiv.11475291 ◽

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

<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 S20 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 Stun corresponding to the axial coordination bond angles.

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Exchange Spin Coupling from Gaussian Process Regression

10.26434/chemrxiv.12589541.v3 ◽

2020 ◽

Author(s):

Marc Philipp Bahlke ◽

Natnael Mogos ◽

Jonny Proppe ◽

Carmen Herrmann

Keyword(s):

Machine Learning ◽

Gaussian Process ◽

Gaussian Process Regression ◽

Molecular Magnets ◽

Molecular Structures ◽

Spin Coupling ◽

Structure Property ◽

Data Set ◽

Uncertainty Estimates

Heisenberg exchange spin coupling between metal centers is essential for describing and understanding the electronic structure of many molecular catalysts, metalloenzymes, and molecular magnets for potential application in information technology. We explore the machine-learnability of exchange spin coupling, which has not been studied yet. We employ Gaussian process regression since it can potentially deal with small training sets (as likely associated with the rather complex molecular structures required for exploring spin coupling) and since it provides uncertainty estimates (“error bars”) along with predicted values. We compare a range of descriptors and kernels for 257 small dicopper complexes and find that a simple descriptor based on chemical intuition, consisting only of copper-bridge angles and copper-copper distances, clearly outperforms several more sophisticated descriptors when it comes to extrapolating towards larger experimentally relevant complexes. Exchange spin coupling is similarly easy to learn as the polarizability, while learning dipole moments is much harder. The strength of the sophisticated descriptors lies in their ability to linearize structure-property relationships, to the point that a simple linear ridge regression performs just as well as the kernel-based machine-learning model for our small dicopper data set. The superior extrapolation performance of the simple descriptor is unique to exchange spin coupling, reinforcing the crucial role of choosing a suitable descriptor, and highlighting the interesting question of the role of chemical intuition vs. systematic or automated selection of features for machine learning in chemistry and material science.

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Correlating Blocking Temperatures in Single Molecule Magnets with Raman Relaxation

10.26434/chemrxiv.7067669 ◽

2018 ◽

Author(s):

Marcus J. Giansiracusa ◽

Andreas Kostopoulos ◽

George F. S. Whitehead ◽

David Collison ◽

Floriana Tuna ◽

...

Keyword(s):

Relaxation Time ◽

Single Molecule ◽

Energy Barrier ◽

Thermal Relaxation ◽

Relaxation Mechanism ◽

Blocking Temperature ◽

Single Molecule Magnets ◽

Single Molecule Magnet ◽

Key Parameter

We report a six coordinate DyIII single-molecule magnet (SMM) with an energy barrier of 1110 K for thermal relaxation of magnetization. The sample shows no retention of magnetization even at 2 K and this led us to find a good correlation between the blocking temperature and the Raman relaxation regime for SMMs. The key parameter is the relaxation time (𝜏switch) at the point where the Raman relaxation mechanism becomes more important than Orbach.

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A Combined Spin-Flip and IP/EA Approach for Handling Spin and Spatial Degeneracies: Application to Double Exchange Systems

10.26434/chemrxiv.7445939.v1 ◽

2018 ◽

Author(s):

Shannon Houck ◽

Nicholas Mayhall

Keyword(s):

Single Molecule ◽

Double Exchange ◽

Computational Effort ◽

Strongly Correlated ◽

Single Molecule Magnets ◽

New Approach ◽

Spin Flip ◽

Model Hamiltonian ◽

Simultaneous Existence ◽

Exchange Parameters

<div>Many multiconfigurational systems, such as single-molecule magnets, are difficult to study using traditional computational methods due to the simultaneous existence of both spin and spatial degeneracies. In this work, a new approach termed n-spin-flip Ionization Potential/Electron Affinity (nSF-IP or nSF-EA) is introduced which combines the spin-flip method of Anna Krylov with particle-number changing IP/EA methods. We demonstrate the efficacy of the approach by applying it to the strongly-correlated N2+ as well as several double exchange systems. We also demonstrate that when these systems are well-described by a double exchange model Hamiltonian, only 1SF-IP/EA is required to extract the double exchange parameters and accurately predict energies for the low-spin states. This significantly reduces the computational effort for studying such systems. The effects of including additional excitations (using a RAS-nSF-IP/EA scheme) are also examined, with particular emphasis on hole and particle excitations.</div>

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A Combined Spin-Flip and IP/EA Approach for Handling Spin and Spatial Degeneracies: Application to Double Exchange Systems

10.26434/chemrxiv.7445939 ◽

2018 ◽

Author(s):

Shannon Houck ◽

Nicholas Mayhall

Keyword(s):

Single Molecule ◽

Double Exchange ◽

Computational Effort ◽

Strongly Correlated ◽

Single Molecule Magnets ◽

New Approach ◽

Spin Flip ◽

Model Hamiltonian ◽

Simultaneous Existence ◽

Exchange Parameters

<div>Many multiconfigurational systems, such as single-molecule magnets, are difficult to study using traditional computational methods due to the simultaneous existence of both spin and spatial degeneracies. In this work, a new approach termed n-spin-flip Ionization Potential/Electron Affinity (nSF-IP or nSF-EA) is introduced which combines the spin-flip method of Anna Krylov with particle-number changing IP/EA methods. We demonstrate the efficacy of the approach by applying it to the strongly-correlated N2+ as well as several double exchange systems. We also demonstrate that when these systems are well-described by a double exchange model Hamiltonian, only 1SF-IP/EA is required to extract the double exchange parameters and accurately predict energies for the low-spin states. This significantly reduces the computational effort for studying such systems. The effects of including additional excitations (using a RAS-nSF-IP/EA scheme) are also examined, with particular emphasis on hole and particle excitations.</div>

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A Brief Review on Dual Target of PARP1 and STAT3 for Cancer Therapy: A Novel Perception

Current Enzyme Inhibition ◽

10.2174/1573408016666200316114209 ◽

2020 ◽

Vol 16 (2) ◽

pp. 115-134

Author(s):

Kaviarasan Lakshmanan ◽

Gowramma Byran ◽

Manal Mohammed

Keyword(s):

Signaling Pathways ◽

Single Molecule ◽

Treatment Options ◽

Poor Response ◽

Cytotoxic Agents ◽

Acquired Drug Resistance ◽

Single Target ◽

New Strategy ◽

Cancer Multiple ◽

Almost All

Background: Cancer is a disease characterized by the uncontrolled growth and spread of abnormal cells. Around the world, over 10 million cancer cases occur annually. Half of all men and one-third of all women will develop some form of cancer during their lifetime. It is one of the most feared diseases, primarily because half of those diagnosed with cancer die from it. There are several treatments available for cancer. Almost all traditional cytotoxic agents suffer from severe toxicities and other undesirable side effects. Objective: In recent years, the development of targeted medicines has made significant achievements. Unfortunately, though these agents can block key regulators of signaling pathways in cancer, multiple compensatory pathways always attenuate pharmacological effect of single-target drugs. In addition, poor response rates and acquired drug resistance also represent a significant barrier to widespread use of targeted medicines. More recently, a number of combinatorial therapies have expanded treatment options, which can directly block several key signaling pathways and create a synergistic effect. Conclusion: Therefore, in order to overcome these barriers, the present investigation aims to develop a new strategy for designing a single molecule with inhibition of two receptors (PARP1 and STAT3) simultaneously and producing enhanced anti-cancer activity with less and/or null toxicity.

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