Using N-Heterocyclic Carbenes as Weak Equatorial Ligands to Design Single-Molecule Magnets: Zero-Field Slow Relaxation in Two Octahedral Dysprosium(III) Complexes

In continuation of our work on supramolecular architectures of single-molecule magnets (SMMs) as a promising strategy in developing their magnetic performance, in this paper we report the synthesis and single crystal X-ray structure of the centered triangular tetrairon(III) SMM, [Fe4(PhpPy)2(dpm)6], Fe4 (Hdpm = dipivaloylmethane, H3PhpPy = 2-(hydroxymethyl)-2-(4-(pyridine-4-yl)phenyl)propane-1,3-diol), and its assembly in the coordination polymer {[Fe4(PhpPy)2(dpm)6Ag](ClO4)}n, Fe4Ag, upon reaction with silver(I) perchlorate. Thanks to the presence of the pyridyl rings on the two tripodal ligands, Fe4 behaves as divergent ditopic linker, and due to the Fe4:AgClO4 1:1 ratio, Fe4Ag probably possesses a linear arrangement in which silver(I) ions are linearly coordinated by two nitrogen atoms, forming 1D chains whose positive charge is balanced by the perchlorate anions. The stabilization of such a polymeric structure can be ascribed to the long distance between the two donor nitrogen atoms (23.4 Å) and their donor power. Fe4Ag shows slow relaxation of the magnetization which follows a thermally activated process with Ueff/kB = 11.17(18) K, τ0 = 2.24(17) 10−7 s in zero field, and Ueff/kB = 14.49(5) K, τ0 = 3.88(8) 10−7 s in 1-kOe applied field, in line with what reported for tetrairon(III) SMMs acting as building blocks in polymeric structures.

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Vibrational Coherences in Manganese Single-molecule Magnets after Ultrafast Photoexcitation

10.26434/chemrxiv.7485011.v1 ◽

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

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−1, 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.

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Magnetic field and dilution effects on the slow relaxation of {Er3} triangle-based arsenotungstate single-molecule magnets

Dalton Transactions ◽

10.1039/d0dt01831g ◽

2020 ◽

Vol 49 (35) ◽

pp. 12458-12465 ◽

Cited By ~ 1

Author(s):

Hanhan Chen ◽

Lin Sun ◽

Jinpeng Zhang ◽

Zikang Xiao ◽

Pengtao Ma ◽

...

Keyword(s):

Magnetic Field ◽

Single Molecule ◽

Magnetic Relaxation ◽

Slow Relaxation ◽

Relaxation Processes ◽

Single Molecule Magnets ◽

Thermally Activated ◽

Slow Magnetic Relaxation ◽

Dilution Effects

Triangular {Er3} cluster containing POM exhibits field-induced two thermally activated relaxation processes. Whereas, the diamagnetic dilution sample indicates slow magnetic relaxation with the QTM being partially suppressed.

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Slow Relaxation of the Magnetization in Bis-Decorated Chiral Helicene-Based Coordination Complexes of Lanthanides

Magnetochemistry ◽

10.3390/magnetochemistry4030039 ◽

2018 ◽

Vol 4 (3) ◽

pp. 39 ◽

Cited By ~ 5

Author(s):

Jessica Flores Gonzalez ◽

Vincent Montigaud ◽

Nidal Saleh ◽

Olivier Cador ◽

Jeanne Crassous ◽

...

Keyword(s):

Magnetic Properties ◽

Ab Initio Calculations ◽

Ab Initio ◽

Single Molecule ◽

Crystalline Phase ◽

Coordination Complexes ◽

Slow Relaxation ◽

Single Molecule Magnets ◽

Racemic Form

The complexes [Ln2(hfac)6(L)]·nC6H14 (Ln = Dy (1) n = 0, Yb (2) n = 1) with the L chiral 3,14-di-(2-pyridyl)-4,13-diaza[6]helicene ligand (hfac− = 1,1,1,5,5,5-hexafluoroacetylacetonate) have been synthesized in their racemic form and structurally and magnetically characterized. Both complexes behave as field-induced single molecule magnets in the crystalline phase. These magnetic properties were rationalized by ab initio calculations.

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Switching slow relaxation in a MnIII3MnIV cluster: an example of grafting single-molecule magnets onto polyoxometalates

Chemical Communications ◽

10.1039/b925947c ◽

2010 ◽

Vol 46 (16) ◽

pp. 2760 ◽

Cited By ~ 81

Author(s):

Xikui Fang ◽

Manfred Speldrich ◽

Helmut Schilder ◽

Rui Cao ◽

Kevin P. O'Halloran ◽

...

Keyword(s):

Single Molecule ◽

Slow Relaxation ◽

Single Molecule Magnets

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By Design: A Macrocyclic 3d–4f Single-Molecule Magnet with Quantifiable Zero-Field Slow Relaxation of Magnetization

Inorganic Chemistry ◽

10.1021/ic302735j ◽

2013 ◽

Vol 52 (6) ◽

pp. 3236-3240 ◽

Cited By ~ 56

Author(s):

Humphrey L. C. Feltham ◽

Rodolphe Clérac ◽

Liviu Ungur ◽

Liviu F. Chibotaru ◽

Annie K. Powell ◽

...

Keyword(s):

Single Molecule ◽

Slow Relaxation ◽

Zero Field ◽

Single Molecule Magnet

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Synthesis, structure, magnetic and luminescence properties of two dysprosium single-molecule magnets based on phenoxide dye ligands

CrystEngComm ◽

10.1039/d0ce00055h ◽

2020 ◽

Vol 22 (11) ◽

pp. 1909-1913

Author(s):

Jérôme Long ◽

Alexander N. Selikhov ◽

Ekaterina Mamontova ◽

Konstantin A. Lyssenko ◽

Yannick Guari ◽

...

Keyword(s):

Single Molecule ◽

Slow Relaxation ◽

Luminescence Properties ◽

Single Molecule Magnets

We report two dysprosium complexes based on phenoxide dye ligands and showing slow relaxation of their magnetization.

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See-Saw Shaped Dy(III) Single-Molecule Magnets with High Anisotropy Barriers

10.26434/chemrxiv.11673927 ◽

2020 ◽

Author(s):

Katie L. M. Harriman ◽

Jesse Murillo ◽

Elizaveta A. Suturina ◽

Skye Fortier ◽

Muralee Murugesu

Keyword(s):

Magnetic Susceptibility ◽

Single Molecule ◽

Molecular Geometry ◽

High Energy ◽

Zero Field ◽

Relaxation Dynamics ◽

Single Molecule Magnets ◽

Ancillary Ligands ◽

Spin Reversal ◽

Magnetic Spin

Utilizing a terphenyl bisanilide ligand, two Dy(III) complexes [K(DME)x][LArDy(X)2] (LAr = {C6H4[(2,6-iPrC6H3)NC6H4]2}2-), X = Cl (1) and X = I (2) were synthesized. The ligand imposes an unusual see-saw shaped molecular geometry leading to a coordinatively unsaturated complex with near-linear N-Dy-N (avg. 159.9° for1 and avg. 160.3o for 2) bond angles. These complexes exhibit Single-Molecule Magnet (SMM) behavior with significant uniaxial magnetic anisotropy as a result of the transverse coordination of the bisanlide ligand which yields high energy barriers to magnetic spin reversal of Ueff = 1334 K/ 927cm-1 (1) and 1299 K/ 903 cm-1 (2) in zero field. Magneto-structural correlations are discussed with the goal of finding a link between halide ancillary ligands in the structurally analogous complexes and the through barrier relaxation dynamics observed in the ac magnetic susceptibility, despite the similar dc magnetic susceptibility for compounds 1 and 2. Ab initio calculations reveal that the dominant crystal field of the bisanilide ligand controls the orientation of the main magnetic axis which runs nearly parallel to the N-Dy-N bonds, and defines the height of the energy barrier. Thus, further validating the use of transverse ligands to enhance the SMM properties of Dy(III) ions.

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