Toward Molecular Magnets of Organic Origin via Anion−π Interaction Involving <i>m</i>-Aminyl Diradical: A Theoretical Study

Bhattacharya, Debojit; Shil, Suranjan; Misra, Anirban; Bytautas, Laimutis; Klein, Douglas J.

doi:10.1021/acs.jpca.6b09666

Cited by 12 publications

(19 citation statements)

References 143 publications

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“…The spin–spin interaction between the unpaired electrons in the diradicals is associated with the average distance between unpaired spins . The decrease of the centroid distance between SOMOα and SOMOβ results in the strengthening spin–spin interaction in the BS state, which is an influential factor in magnetic anisotropy.…”

Section: Resultsmentioning

confidence: 99%

External Electric Field Effects on AFM-like Magnetism in Nitroxide-Functionalized C⁺:C Base Pair

Zhao

Cui

Lyu

et al. 2023

J. Chem. Inf. Model.

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In this work, we computationally designed a set of nitroxide diradical base pairs (rC + :rC) to propose promising magnetic building blocks for spintronic or magnetic molecular materials. C + :C12 is found to possess a considerably large antiferromagnetic-like (AFM-like) spin-coupling magnitude (J = −3286.681 cm −1 ) and sensitive magnetic responses to the external electric field. Especially, the presence of the Y direction field that is oriented perpendicular to intermolecular hydrogen bonds has the greatest influence on the magnetic exchange interaction (J being from −2549.578 to −4231.286 cm −1 , ΔJ Y = 1681.708 cm −1 ), which could be understood by two simultaneously occurring effects. On the one hand, the external electric field in the −Y direction can regulate the charge polarization of negative and positive electrostatic potentials on C12 moiety and further facilitate the spin transport property. On the other hand, with increasing electric field strength on the −Y axis, the spin density on diradical sources diminishes and that on the coupler increases, which can lead to a homogenous spin-density distribution. The achieved understanding provides a new strategy for designing self-assembly magnetic nanomaterials or nanodevices and enhancing the AFM coupling through the assistance of external electric field.

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Section: Resultsmentioning

confidence: 99%

External Electric Field Effects on AFM-like Magnetism in Nitroxide-Functionalized C⁺:C Base Pair

Zhao

Cui

Lyu

et al. 2023

J. Chem. Inf. Model.

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“…Although increasing the size of the doped nanoclusters slightly lowers the diradical character, all the NV nanoclusters have large diradical characters and can be viewed as standard diradicals with the expected AFM or FM spin couplings (Table and Table S2). , The above observations inspire us to use the doping modification to assign the NV nanoclusters expected magnetic coupling characteristics and magnitudes, together with controlling the size of the nanoclusters, for designing the targeted endohedral σ-diradical NV diamond nanocluster magnets.…”

Section: Results and Discussionmentioning

confidence: 99%

Endohedral σ-Diradical Nitrogen-Vacancy Diamond Nanoclusters with a Confined Magnetic Space and Strong Electronic Spin Couplings

et al. 2022

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The electronic properties and their modulations for the nitrogen-vacancy (NV) centers in various nanoscale diamonds are of profound current interest because of their potential applications. However, although the NV centers as chromophores in diamond are the most widely studied, surprisingly, little is known about their magnetic spin coupling properties up to now. Here, we for the first time show, using the spin-polarized DFT calculations, that the NV centers can act as unique endohedral σ-diradical magnets in diamond nanoclusters and exhibit quite strong ferromagnetic (FM) or antiferromagnetic (AFM) spin coupling characteristics due to their unique endotetrahedral structures with favorable radical–radical contacts. Although the neutral NV center (NV0) in its doublet ground state exhibits quite strong AFM spin coupling among three radical C-sites (i.e., an AFM triradical center), interestingly, excess electron injection can convert it to a FM diradical magnet (i.e., the triplet ground state NV–) with almost unchanged J-coupling magnitude, and the J-coupling of the nanocluster can be noticeably enhanced by F-termination of the surface due to triradical spin delocalization mediated by excess electron. However, interior modification (one C in the endotetrahedron core is substituted by N or B or is hydrogenated) can assign the nanocluster perfect AFM diradical character. The spin coupling strength presents a quasilinear correlation with the distance between the two C radicals in the NV core for the same size of the clusters and a high linear correlation with the energy difference between two singly occupied molecular orbitals. Clearly, the FM and AFM couplings as well as their switching behavior in such NV defect diamond nanoclusters featuring the endohedral σ-diradicals are a novel type of promising magnetic material motifs. These findings open up promising spintronic application prospects of the NV diamonds and provide helpful information for the design of inorganic magnetic materials and logic devices.

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“…Therefore, an application of these three pairs of tautomers in the field of magnetic information storing or switch controlling might be acceptable. Moreover, recent studies , have shown a possible method to produce high-spin coupling molecular magnets with triplet ground state by introducing halide ions, which may expand the applications of our designs to low-to-high spin transformation (see the Supporting Information for details). Of course, apart from all of the discussions above, the specific way to make full use of them needs more in-depth studies.…”

Section: Resultsmentioning

confidence: 99%

Rational Design of Organic Magnets with Switchable Two-Way Couplers: Magnetic Modulation or Switching through Lactam–Lactim Tautomerization

Chen

Deng

et al. 2019

J. Phys. Chem. C

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Lactam−lactim tautomerism, which features a typical prototropic process, has been widely applied to various functional processes. Here, we use it to design the magnetismtunable organic magnets. Taking experimentally reported phenazine-N,N′-dioxide (PDO) as template in which two nitroxide groups act as spin sources and two ortho-phendiyl groups act as two couplers, we further modify one coupler through replacing a −CC− unit of an ortho-phendiyl by an amide (−CONH−) at three different positions, forming three switchable molecular magnets. Calculations reveal intriguing magnetic modulation or switching phenomena through tautomerization. That is, all lactim structures and PDO exhibit extremely strong antiferromagnetic spin couplings with magnetic coupling constants J ranging from −2485.7 to −2732.4 cm −1 , while the lactam structures are diamagnetic or moderately strong antiferromagnetic with a J of −1703.6 cm −1 , depending on different locations of the introduced amide/imide units. Strong spin couplings (including excessive couplings in diamagnetic cases) in all six molecules and PDO can be interpreted by proximity of two nitroxide groups, good planarity, and conjugation, while the reason for the differences in magnetic characteristics of three lactam forms is that the destruction of aromaticity induces two types of rearrangement of chemical bonds, which leads to opposite changes of the spin coupling between two radical units. Besides, the role of each coupler, ring aromaticity, Mulliken spin densities, and molecular orbitals are analyzed for the understanding of magnetic regulation. Double lactam−lactim tautomerization through modifying two couplers with amide/imide units, different orientations of hydroxyl H in lactim structures, and tautomerization energetics assisted by solvent molecules are also discussed. This work provides a promising strategy for rational design of organic molecular magnetic switches with two switchable spin communication channels.

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Toward Molecular Magnets of Organic Origin via Anion−π Interaction Involving m-Aminyl Diradical: A Theoretical Study

Cited by 12 publications

References 143 publications

External Electric Field Effects on AFM-like Magnetism in Nitroxide-Functionalized C⁺:C Base Pair

External Electric Field Effects on AFM-like Magnetism in Nitroxide-Functionalized C⁺:C Base Pair

Endohedral σ-Diradical Nitrogen-Vacancy Diamond Nanoclusters with a Confined Magnetic Space and Strong Electronic Spin Couplings

Rational Design of Organic Magnets with Switchable Two-Way Couplers: Magnetic Modulation or Switching through Lactam–Lactim Tautomerization

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Toward Molecular Magnets of Organic Origin via Anion−π Interaction Involving m-Aminyl Diradical: A Theoretical Study

Cited by 12 publications

References 143 publications

External Electric Field Effects on AFM-like Magnetism in Nitroxide-Functionalized C+:C Base Pair

External Electric Field Effects on AFM-like Magnetism in Nitroxide-Functionalized C+:C Base Pair

Endohedral σ-Diradical Nitrogen-Vacancy Diamond Nanoclusters with a Confined Magnetic Space and Strong Electronic Spin Couplings

Rational Design of Organic Magnets with Switchable Two-Way Couplers: Magnetic Modulation or Switching through Lactam–Lactim Tautomerization

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External Electric Field Effects on AFM-like Magnetism in Nitroxide-Functionalized C⁺:C Base Pair

External Electric Field Effects on AFM-like Magnetism in Nitroxide-Functionalized C⁺:C Base Pair