ESR study of spin-crossover complex [MnIII(taa)] using pulsed high magnetic field

Kimura, Shojiro; Otani, Tomohito; Narumi, Yasuo; Kindo, Koichi; Nakano, Motohiro; Matsubayashi, Gen‐etsu

doi:10.1016/j.jmmm.2003.12.1334

Cited by 16 publications

(4 citation statements)

References 7 publications

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“…Thus, for an isolated HS molecule, an enhanced distortion of the C 3 symmetry is obtained. Although the X-ray structure of [Mn(pyrol) 3 tren] reveals an effective C 3 symmetry, 3 the dynamic effects observed by means of dielectric and high frequency ESR measurements, [5][6][7][8] as well as the deviations in the thermal displacement parameters in the X-ray structure 10 reveal the JT distortion. The distortion is practically absent in the optimised structure of the LS complex: the Mn-N pyrr distances are 1.976, 1.986 and 1.996 A ˚, while the Mn-N imine distances are 2.046 and 2.057 A ˚.…”

Section: Resultsmentioning

confidence: 99%

“…Energy difference between spin isomers. The multiplet splitting E s was calculated on the basis of the B3LYP* functional 8 because it proved to be quite effective in assessing this value for Fe(II) complexes. 20 The calculated values show that, for [Mn(pyrol) 3 tren], the HS state derived for the isolated molecule lies ca.…”

Section: Resultsmentioning

confidence: 99%

“…2 The best studied SCO d 4 system is the mononuclear complex of the tripodal pyrrole anion containing a Schiff base of formula [Mn III (pyrol) 3 tren] {(Hpyrol) 3 tren = tris(1-(2-azolyl)-2-azabuten-4-yl)amine)}. [3][4][5][6][7][8][9][10] The spin transition from the high-spin state (HS, 5 E g ) to the low-spin state (LS, 3 T g ) occurs abruptly at about 44 K, as observed by magnetic susceptibility 3 and heat capacity measurements. 4 It has been suggested, on the basis of solid state Raman spectra, that [Mn III (pyrol) 3 tren] does not undergo a classical SCO behaviour in which the vibrational entropy is dominant, 5 contrary to the suggestion that the molecular vibrations in Fe(II) SCO compounds 11 contribute a major part to the entropy change accompanying spin crossover.…”

Section: Introductionmentioning

confidence: 99%

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Estimate of the vibrational contribution to the entropy change associated with the spin transition in the d⁴systems [Mn^III(pyrol)₃tren] and [Cr^II(depe)₂I₂]

Garcia

Paulsen

Schünemann

et al. 2007

Phys. Chem. Chem. Phys.

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The vibrational contribution to DeltaS of the low-spin ((3)T(1)) to high-spin ((5)E) spin transition in two 3d(4) octahedral systems [Mn(III)(pyrol)(3)tren] and [Cr(depe)(2)I(2)] have been estimated by means of DFT calculations (B3LYP/CEP-31G) of the vibrational normal-modes frequencies. The obtained value at the transition temperature for the Mn(iii) complex is DeltaS(vib)(44 K) = 6.3 J K(-1) mol(-1), which is comparable with the proposed Jahn-Teller contribution of R ln3 = 9.1 J K(-1) mol(-1) and which is approximately half of the experimentally determined 13.8 J K(-1) mol(-1). The corresponding value for the Cr(ii) complex is DeltaS(vib)(171.45 K) = 46.5 J K(-1) mol(-1), as compared to the experimental value of 39.45 J K(-1) mol(-1). The analysis of the vibrational normal modes reveals that for the d(4) systems under study, contrary to Fe(ii) d(6) systems, not all metal-ligand stretching vibrations make a contribution. For the Mn(iii) complex, the only vibration that contributes to DeltaS(vib) involve the nitrogens occupying the Jahn-Teller axis, while in the case of Cr(ii) the contributing vibrations involve the Cr-I bonds. Low-frequency modes due to ring vibrations, metal-ligand bending and movement of the molecule as a whole also contribute to the vibrational entropy associated with the spin transition.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Estimate of the vibrational contribution to the entropy change associated with the spin transition in the d⁴systems [Mn^III(pyrol)₃tren] and [Cr^II(depe)₂I₂]

Garcia

Paulsen

Schünemann

et al. 2007

Phys. Chem. Chem. Phys.

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“…This was one of the first Mn 3+ based materials to show an SST. With increasing temperature T or magnetic field H the spin transitions from the low spin (LS) S = 1 (, ) to the high spin (HS) S = 2 (, ) state as an electron changes orbital 29,30 . The T -induced SST at 48 K is illustrated in the heat capacity C p ( T ) and the dielectric constant data in Fig.…”

Section: Introductionmentioning

confidence: 99%

Magnetoelectric behavior via a spin state transition

Saito

Zhang

et al. 2019

Nat Commun

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In magnetoelectric materials, magnetic and dielectric/ferroelectric properties couple to each other. This coupling could enable lower power consumption and new functionalities in devices such as sensors, memories and transducers, since voltages instead of electric currents are sensing and controlling the magnetic state. We explore a different approach to magnetoelectric coupling in which we use the magnetic spin state instead of the more traditional ferro or antiferromagnetic order to couple to electric properties. In our molecular compound, magnetic field induces a spin crossover from the S = 1 to the S = 2 state of Mn 3+ , which in turn generates molecular distortions and electric dipoles. These dipoles couple to the magnetic easy axis, and form different polar, antipolar and paraelectric phases vs magnetic field and temperature. Spin crossover compounds are a large class of materials where the spin state can modify the structure, and here we demonstrate that this is a route to magnetoelectric coupling.

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Cooperative Spin Transition in a Mononuclear Manganese(III) Complex

et al. 2012

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Ein 8 K großes Hysteresefenster kennzeichnet den vollständigen, kooperativen Spinübergang in einem einkernigen MnIII‐Komplex. Raman‐Spektren, die beim Aufheizen und beim Abkühlen bei der gleichen Temperatur aufgenommen wurden, bestätigen die elektronische Bistabilität innerhalb der Hystereseschleife. Grund ist ein Ordnungs‐Unordnungs‐Übergang im PF6−‐Gegenion, der sich auf die H‐Brücken‐gebundenen 1D‐Ketten auswirkt, die benachbarte Kationen verbinden.

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ESR study of spin-crossover complex [MnIII(taa)] using pulsed high magnetic field

Cited by 16 publications

References 7 publications

Estimate of the vibrational contribution to the entropy change associated with the spin transition in the d⁴systems [Mn^III(pyrol)₃tren] and [Cr^II(depe)₂I₂]

Estimate of the vibrational contribution to the entropy change associated with the spin transition in the d⁴systems [Mn^III(pyrol)₃tren] and [Cr^II(depe)₂I₂]

Magnetoelectric behavior via a spin state transition

Cooperative Spin Transition in a Mononuclear Manganese(III) Complex

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ESR study of spin-crossover complex [MnIII(taa)] using pulsed high magnetic field

Cited by 16 publications

References 7 publications

Estimate of the vibrational contribution to the entropy change associated with the spin transition in the d4systems [MnIII(pyrol)3tren] and [CrII(depe)2I2]

Estimate of the vibrational contribution to the entropy change associated with the spin transition in the d4systems [MnIII(pyrol)3tren] and [CrII(depe)2I2]

Magnetoelectric behavior via a spin state transition

Cooperative Spin Transition in a Mononuclear Manganese(III) Complex

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Estimate of the vibrational contribution to the entropy change associated with the spin transition in the d⁴systems [Mn^III(pyrol)₃tren] and [Cr^II(depe)₂I₂]

Estimate of the vibrational contribution to the entropy change associated with the spin transition in the d⁴systems [Mn^III(pyrol)₃tren] and [Cr^II(depe)₂I₂]