Slow Magnetic Relaxation in Mononuclear Octahedral Manganese(III) Complexes with Dibenzoylmethanide Ligands

Chen, Lei; Wang, Jing; Liu, Yuan‐Zhong; Song, You; Chen, Xue‐Tai; Zhang, Yi‐Quan; Xue, Zi‐Ling

doi:10.1002/ejic.201402964

Cited by 41 publications

(11 citation statements)

References 86 publications

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“…Long et al reported the slow magnetic relaxation behaviors of a low-coordinate trigonal-pyramidal four-coordinate Fe(II) complex, [(tpa Mes )Fe] − , in the presence of H dc , and ascribed them to its large axial magnetic anisotropy arising from the SOC at the iron site . A number of mononuclear transition metal SMMs including V(IV), Cr(II), Mn(III), − Mn(IV), Fe(I), Fe(II), , Fe(III), Co(I), Co(II), − Ni(I), , Ni(II), , Ni(III), Ru(III), and Re(IV) , complexes have been reported to date, although most of these need the H dc to exhibit the slow magnetic relaxations. Recently, a linear Co(II) complex has been reported to possess a maximum orbital angular momentum to give J = 9/2, and thus shows a magnetic relaxation barrier at a temperature as high as 70 K …”

Section: Introductionmentioning

confidence: 99%

Synthesis of a Neutral Mononuclear Four-Coordinate Co(II) Complex Having Two Halved Phthalocyanine Ligands That Shows Slow Magnetic Relaxations under Zero Static Magnetic Field

et al. 2019

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Syntheses of a novel pseudotetrahedral four-coordinate mononuclear Co(II) complex that has two halved phthalocyanine moieties as the ligands, [Co(half-Pc)2] (1), and its magnetic properties as a single molecule magnet (SMM) are reported. A one pot reaction of phthalonitrile and lithium methoxide followed by the coordination to a Co(II) ion gave 1 as an orange solid in a moderate yield. X-ray crystallography on 1 reveals tetragonally distorted coordination geometry around the Co(II) ion. The M–HT –1 plots suggest that 1 has large axial magnetic anisotropy. The ac magnetic susceptibility data of the magnetically diluted 1 (dil.1) clearly show that the complex acts as an SMM even in the absence of the external static magnetic field (H dc). The influence of intermolecular and intramolecular interactions for the magnetic relaxation behaviors has been discussed by comparison of the magnetic data of 1 and dil.1. The Orbach process is suggested as the predominant mechanism of magnetic relaxations in the high-temperature range, and the Arrhenius plots provide the effective relaxation energy barrier and pre-exponential factor of U eff = 54.0 cm–1 and τ0 = 3.17 × 10–10 s, respectively. The direct estimation of the axial anisotropic parameter of 1 was successfully performed by high-field, multifrequency ESR measurements up to 55 T and 2.5 THz. The evaluated axial zero-field splitting (ZFS) energy of 57.0 cm–1 is comparable to the U eff energy, confirming that the magnetic relaxations are initiated by the thermal excitation from the ground |M S ⟩ = |±3/2⟩ states to the |±1/2⟩ states in the high-temperature range. The results of the ab initio calculations based on the CAS(7,5) SCF wave functions indicate that the ground states of 1 consist mainly of |M S ⟩ = |±3/2⟩ states, while the first excited states are the mixture of |M S ⟩ = |+1/2⟩ and |−1/2⟩.

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Section: Introductionmentioning

confidence: 99%

Synthesis of a Neutral Mononuclear Four-Coordinate Co(II) Complex Having Two Halved Phthalocyanine Ligands That Shows Slow Magnetic Relaxations under Zero Static Magnetic Field

et al. 2019

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“…31−33 One of the first examples of a SIM containing the Mn III ion was described by Ishikawa and co-workers, a Mn III -salen-type complex with an energy barrier of 16.5 K. 34 Prior to our work, just one Mn III -based SIM containing a βdiketonate ligand has been reported in the literature. 35 In a previous article, we described a useful synthetic route toward [Mn III 2 Ln III 2 ] (Ln = Gd, Tb, Dy) complexes with SMM behavior. 36 Herein, we report the synthesis, crystal structure, and magnetic properties of three new binuclear systems containing Mn III and a lanthanide ion (La III (1), Pr III (2), and Eu III (3)) obtained using the same methodology reported in the work mentioned above.…”

Section: ■ Introductionmentioning

confidence: 99%

Synthesis, Crystal Structures, and EPR Studies of First Mn^IIILn^III Hetero-binuclear Complexes

et al. 2017

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A new family of binuclear complexes [MnLn(dpm)(MeO)(MeOH)] is reported (where Ln = La (1), Pr (2), and Eu(3)). These compounds were obtained from a one-pot reaction between 2,2,6,6-tetramethyl-3,5-heptanodione (Hdpm), Mn, and the respective Ln salt in the presence of sodium methoxide. The derivative containing the diamagnetic ion La has been synthesized in order to characterize the local anisotropy of the Mn ion. High-field electron paramagnetic resonance (HFEPR) spectroscopy shows that the Mn ion, with an elongated octahedral geometry in all compounds, has a significant axial zero-field splitting and a small rhombic anisotropy. Additionally, the HFEPR measurements indicate that there is almost no exchange between the spin carriers in these compounds, all of which exhibit field-induced slow relaxation of the magnetization.

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“…[2] In contrast, SIMs depend on the magnetic properties of as ingle paramagnetic ion generally in ah igh spin state. Since the discovery of bis(phthalocyanine)-lanthanide(III) complexes, further examples of SIMs that contain otherl anthanides [3][4][5][6][7][8][9][10][11][12][13][14][15][16] and actinides have been reported, [17][18][19][20][21] followed by first-and third-row transition-metal ions, [22] such as Fe II , [23][24][25][26][27][28][29] Co II , [30][31][32][33][34] Mn III , [35][36][37][38][39] Ni I , [40] and Re IV . [41] A variety of ligands, which serve to controlt he molecular symmetry of the metal-coordinatione nvironmenta nd thus the zero-field splitting (zfs) of the final complex, were used in the design andp reparation of theseSIMs.…”

Section: Introductionmentioning

confidence: 99%

Field‐Induced Slow Magnetic Relaxation in a Mononuclear Manganese(III)–Porphyrin Complex

Pascual‐Álvarez

Vallejo

Pardo

et al. 2015

Chemistry A European J

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We report on a novel manganese(III)-porphyrin complex with the formula [Mn(III) (TPP)(3,5-Me2 pyNO)2 ]ClO4 ⋅CH3 CN (2; 3,5-Me2 pyNO=3,5-dimethylpyridine N-oxide, H2 TPP=5,10,15,20-tetraphenylporphyrin), in which the Mn(III) ion is six-coordinate with two monodentate 3,5-Me2 pyNO molecules and a tetradentate TPP ligand to build a tetragonally elongated octahedral geometry. The environment in 2 is responsible for the large and negative axial zero-field splitting (D=-3.8 cm(-1) ), low rhombicity (E/|D|=0.04) of the high-spin Mn(III) ion, and, ultimately, for the observation of slow magnetic-relaxation effects (Ea =15.5 cm(-1) at H=1000 G) in this rare example of a manganese-based single-ion magnet (SIM). Structural, magnetic, and electronic characterizations were carried out by means of single-crystal diffraction studies, variable-temperature direct- and alternating-current measurements and high-frequency and -field EPR spectroscopic analysis followed by quantum-chemical calculations. Slow magnetic-relaxation effects were also observed in the already known analogous compound [Mn(III) (TPP)Cl] (1; Ea =10.5 cm(-1) at H=1000 G). The results obtained for 1 and 2 are compared and discussed herein.

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Slow Magnetic Relaxation in Mononuclear Octahedral Manganese(III) Complexes with Dibenzoylmethanide Ligands

Abstract: The structural characterization and magnetic studies of three mononuclear Mn III complexes based on the dibenzoylmeth-

Cited by 41 publications

References 86 publications

Synthesis of a Neutral Mononuclear Four-Coordinate Co(II) Complex Having Two Halved Phthalocyanine Ligands That Shows Slow Magnetic Relaxations under Zero Static Magnetic Field

Synthesis of a Neutral Mononuclear Four-Coordinate Co(II) Complex Having Two Halved Phthalocyanine Ligands That Shows Slow Magnetic Relaxations under Zero Static Magnetic Field

Synthesis, Crystal Structures, and EPR Studies of First Mn^IIILn^III Hetero-binuclear Complexes

Field‐Induced Slow Magnetic Relaxation in a Mononuclear Manganese(III)–Porphyrin Complex

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Slow Magnetic Relaxation in Mononuclear Octahedral Manganese(III) Complexes with Dibenzoylmethanide Ligands

Abstract: The structural characterization and magnetic studies of three mononuclear Mn III complexes based on the dibenzoylmeth-

Cited by 41 publications

References 86 publications

Synthesis of a Neutral Mononuclear Four-Coordinate Co(II) Complex Having Two Halved Phthalocyanine Ligands That Shows Slow Magnetic Relaxations under Zero Static Magnetic Field

Synthesis of a Neutral Mononuclear Four-Coordinate Co(II) Complex Having Two Halved Phthalocyanine Ligands That Shows Slow Magnetic Relaxations under Zero Static Magnetic Field

Synthesis, Crystal Structures, and EPR Studies of First MnIIILnIII Hetero-binuclear Complexes

Field‐Induced Slow Magnetic Relaxation in a Mononuclear Manganese(III)–Porphyrin Complex

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Synthesis, Crystal Structures, and EPR Studies of First Mn^IIILn^III Hetero-binuclear Complexes