The freeon theory of molecular magnets. III. The linear polyene model

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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The 2 1Ag state in the linear polyene 2,4,6,8,10,12,14,16‐octadecaoctaene

The Journal of Chemical Physics ◽

10.1063/1.455594 ◽

1988 ◽

Vol 89 (9) ◽

pp. 5422-5428 ◽

Cited By ~ 153

Author(s):

Bryan E. Kohler ◽

Charles Spangler ◽

Curtis Westerfield

Keyword(s):

Linear Polyene

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Decoherence measurements in crystals of molecular magnets

Physical Review B ◽

10.1103/physrevb.99.180408 ◽

2019 ◽

Vol 99 (18) ◽

Cited By ~ 1

Author(s):

Gheorghe Taran ◽

Edgar Bonet ◽

Wolfgang Wernsdorfer

Keyword(s):

Molecular Magnets

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Coupled-cluster approach to electron correlation in one dimension. II. Cyclic polyene model in localized basis

Physical Review B ◽

10.1103/physrevb.31.5121 ◽

1985 ◽

Vol 31 (8) ◽

pp. 5121-5142 ◽

Cited By ~ 75

Author(s):

M. Takahashi ◽

J. Paldus

Keyword(s):

Electron Correlation ◽

One Dimension ◽

Coupled Cluster ◽

Cluster Approach ◽

Cyclic Polyene ◽

Polyene Model

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Mixed-valence molecular magnets based on building block: Structures, magnetic properties and DFT analyses

Polyhedron ◽

10.1016/j.poly.2006.09.028 ◽

2007 ◽

Vol 26 (9-11) ◽

pp. 1781-1786 ◽

Cited By ~ 5

Author(s):

Y.C. Chen ◽

G.X. Liu ◽

P.F. Wang ◽

H. Xu ◽

X.M. Ren ◽

...

Keyword(s):

Magnetic Properties ◽

Building Block ◽

Mixed Valence ◽

Molecular Magnets ◽

Block Structures

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XXXIX.—Magnetic Quality in the most open Cubic Arrangement of Molecular Magnets.

Proceedings of the Royal Society of Edinburgh ◽

10.1017/s0370164600011913 ◽

1908 ◽

Vol 28 ◽

pp. 643-651 ◽

Cited By ~ 2

Author(s):

W. Peddie

Keyword(s):

Magnetic Properties ◽

Molecular Magnets ◽

Molecular Arrangement ◽

Good Agreement

In a former paper (Proc. R.S.E., 1905) an investigation was given of the magnetic properties of the closest packed homogeneous cubic arrangement of molecular magnets, and it was found that the results were in good agreement with the observed properties of crystals of magnetite. It was also suggested that a parallel investigation of other cubic arrangements might lead to a discrimination of molecular arrangement, so far as the magnetic constituents are concerned, in actual crystals. To settle this point, if possible, the present investigation was undertaken.

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Dragging Human Mesenchymal Stem Cells with the Aid of Supramolecular Assemblies of Single-Walled Carbon Nanotubes, Molecular Magnets, and Peptides in a Magnetic Field

BioMed Research International ◽

10.1155/2015/143504 ◽

2015 ◽

Vol 2015 ◽

pp. 1-9

Author(s):

Ana Cláudia C. de Paula ◽

Gustavo A. M. Sáfar ◽

Alfredo M. Góes ◽

Marcelo P. Bemquerer ◽

Marcos A. Ribeiro ◽

...

Keyword(s):

Magnetic Field ◽

Carbon Nanotubes ◽

Stem Cells ◽

Supramolecular Assembly ◽

Single Walled Carbon Nanotubes ◽

Molecular Magnets ◽

Multiwalled Carbon ◽

Blood Capillaries ◽

Single Walled Carbon ◽

Walled Carbon Nanotubes

Human adipose-derived stem cells (hASCs) are an attractive cell source for therapeutic applicability in diverse fields for the repair and regeneration of damaged or malfunctioning tissues and organs. There is a growing number of cell therapies using stem cells due to their characteristics of modulation of immune system and reduction of acute rejection. So a challenge in stem cells therapy is the delivery of cells to the organ of interest, a specific site. The aim of this paper was to investigate the effects of a supramolecular assembly composed of single-walled carbon nanotubes (SWCNT), molecular magnets (lawsone-Co-phenanthroline), and a synthetic peptide (FWYANHYWFHNAFWYANHYWFHNA) in the hASCs cultures. The hASCs were isolated, characterized, expanded, and cultured with the SWCNT supramolecular assembly (SWCNT-MA). The assembly developed did not impair the cell characteristics, viability, or proliferation. During growth, the cells were strongly attached to the assembly and they could be dragged by an applied magnetic field of less than 0.3 T. These assemblies were narrower than their related allotropic forms, that is, multiwalled carbon nanotubes, and they could therefore be used to guide cells through thin blood capillaries within the human body. This strategy seems to be useful as noninvasive and nontoxic stem cells delivery/guidance and tracking during cell therapy.

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