Measurement of Extreme hyperfine fields in two-coordinate high-spin Fe2+ complexes by mössbauer Spectroscopy

Essentially Free-Ion Magnetism in the Solid State

Aimee M. Bryan, Chun-Yi Lin, Michio Sorai, Yuji Miyazaki, Helen M. Hoyt, Annelise Hablutzel, Anne Lapointe, William M. Reiff, Philip P. Power, Charles E. Schulz

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

Mössbauer studies of three two-coordinate linear high-spin Fe2+ compounds, namely, Fe{N(SiMe3)(Dipp)}2 (1) (Dipp = C6H3-2,6-iPr2), Fe(OAr′)2 (2) [Ar′ = C6H3-2,6-(C6H3-2,6-iPr2)2], and Fe{C(SiMe3)3}2 (3), are presented. The complexes were characterized by zero- and applied-field Mössbauer spectroscopy (1-3), as well as zero- and applied-field heat-capacity measurements (3). As 1-3 are rigorously linear, the distortion(s) that might normally be expected in view of the Jahn-Teller theorem need not necessarily apply. We find that the resulting very large unquenched orbital angular momentum leads to what we believe to be the largest observed internal magnetic field to date in a high-spin iron(II) compound, specifically +162 T in 1. The latter field is strongly polarized along the directions of the external field for both longitudinal and transverse field applications. For the longitudinal case, the applied field increases the overall hyperfine splitting consistent with a dominant orbital contribution to the effective internal field. By contrast, 2 has an internal field that is not as strongly polarized along a longitudinally applied field and is smaller in magnitude at ca. 116 T. Complex 3 behaves similarly to complex 1. They are sufficiently self-dilute (e.g., Fe···Fe distances of ca. 9-10 Å) to exhibit varying degrees of slow paramagnetic relaxation in zero field for the neat solid form. In the absence of EPR signals for 1-3, we show that heat-capacity measurements for one of the complexes (3) establish a geff value near 12, in agreement with the principal component of the ligand electric field gradient being coincident with the z axis.

Original languageEnglish
Pages (from-to)12100-12107
Number of pages8
JournalInorganic Chemistry
Volume53
Issue number22
DOIs
Publication statusPublished - 2014 Nov 17

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Magnetism
Specific heat
specific heat
Spectroscopy
Ions
Iron compounds
solid state
orbitals
Angular momentum
spectroscopy
Paramagnetic resonance
ions
angular momentum
theorems
Electric fields
Magnetic fields
Ligands
iron
gradients
ligands

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

Cite this

Bryan, Aimee M. ; Lin, Chun-Yi ; Sorai, Michio ; Miyazaki, Yuji ; Hoyt, Helen M. ; Hablutzel, Annelise ; Lapointe, Anne ; Reiff, William M. ; Power, Philip P. ; Schulz, Charles E. / Measurement of Extreme hyperfine fields in two-coordinate high-spin Fe2+ complexes by mössbauer Spectroscopy : Essentially Free-Ion Magnetism in the Solid State. In: Inorganic Chemistry. 2014 ; Vol. 53, No. 22. pp. 12100-12107.
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abstract = "M{\"o}ssbauer studies of three two-coordinate linear high-spin Fe2+ compounds, namely, Fe{N(SiMe3)(Dipp)}2 (1) (Dipp = C6H3-2,6-iPr2), Fe(OAr′)2 (2) [Ar′ = C6H3-2,6-(C6H3-2,6-iPr2)2], and Fe{C(SiMe3)3}2 (3), are presented. The complexes were characterized by zero- and applied-field M{\"o}ssbauer spectroscopy (1-3), as well as zero- and applied-field heat-capacity measurements (3). As 1-3 are rigorously linear, the distortion(s) that might normally be expected in view of the Jahn-Teller theorem need not necessarily apply. We find that the resulting very large unquenched orbital angular momentum leads to what we believe to be the largest observed internal magnetic field to date in a high-spin iron(II) compound, specifically +162 T in 1. The latter field is strongly polarized along the directions of the external field for both longitudinal and transverse field applications. For the longitudinal case, the applied field increases the overall hyperfine splitting consistent with a dominant orbital contribution to the effective internal field. By contrast, 2 has an internal field that is not as strongly polarized along a longitudinally applied field and is smaller in magnitude at ca. 116 T. Complex 3 behaves similarly to complex 1. They are sufficiently self-dilute (e.g., Fe···Fe distances of ca. 9-10 {\AA}) to exhibit varying degrees of slow paramagnetic relaxation in zero field for the neat solid form. In the absence of EPR signals for 1-3, we show that heat-capacity measurements for one of the complexes (3) establish a geff value near 12, in agreement with the principal component of the ligand electric field gradient being coincident with the z axis.",
author = "Bryan, {Aimee M.} and Chun-Yi Lin and Michio Sorai and Yuji Miyazaki and Hoyt, {Helen M.} and Annelise Hablutzel and Anne Lapointe and Reiff, {William M.} and Power, {Philip P.} and Schulz, {Charles E.}",
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Bryan, AM, Lin, C-Y, Sorai, M, Miyazaki, Y, Hoyt, HM, Hablutzel, A, Lapointe, A, Reiff, WM, Power, PP & Schulz, CE 2014, 'Measurement of Extreme hyperfine fields in two-coordinate high-spin Fe2+ complexes by mössbauer Spectroscopy: Essentially Free-Ion Magnetism in the Solid State', Inorganic Chemistry, vol. 53, no. 22, pp. 12100-12107. https://doi.org/10.1021/ic501925e

Measurement of Extreme hyperfine fields in two-coordinate high-spin Fe2+ complexes by mössbauer Spectroscopy : Essentially Free-Ion Magnetism in the Solid State. / Bryan, Aimee M.; Lin, Chun-Yi; Sorai, Michio; Miyazaki, Yuji; Hoyt, Helen M.; Hablutzel, Annelise; Lapointe, Anne; Reiff, William M.; Power, Philip P.; Schulz, Charles E.

In: Inorganic Chemistry, Vol. 53, No. 22, 17.11.2014, p. 12100-12107.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Measurement of Extreme hyperfine fields in two-coordinate high-spin Fe2+ complexes by mössbauer Spectroscopy

T2 - Essentially Free-Ion Magnetism in the Solid State

AU - Bryan, Aimee M.

AU - Lin, Chun-Yi

AU - Sorai, Michio

AU - Miyazaki, Yuji

AU - Hoyt, Helen M.

AU - Hablutzel, Annelise

AU - Lapointe, Anne

AU - Reiff, William M.

AU - Power, Philip P.

AU - Schulz, Charles E.

PY - 2014/11/17

Y1 - 2014/11/17

N2 - Mössbauer studies of three two-coordinate linear high-spin Fe2+ compounds, namely, Fe{N(SiMe3)(Dipp)}2 (1) (Dipp = C6H3-2,6-iPr2), Fe(OAr′)2 (2) [Ar′ = C6H3-2,6-(C6H3-2,6-iPr2)2], and Fe{C(SiMe3)3}2 (3), are presented. The complexes were characterized by zero- and applied-field Mössbauer spectroscopy (1-3), as well as zero- and applied-field heat-capacity measurements (3). As 1-3 are rigorously linear, the distortion(s) that might normally be expected in view of the Jahn-Teller theorem need not necessarily apply. We find that the resulting very large unquenched orbital angular momentum leads to what we believe to be the largest observed internal magnetic field to date in a high-spin iron(II) compound, specifically +162 T in 1. The latter field is strongly polarized along the directions of the external field for both longitudinal and transverse field applications. For the longitudinal case, the applied field increases the overall hyperfine splitting consistent with a dominant orbital contribution to the effective internal field. By contrast, 2 has an internal field that is not as strongly polarized along a longitudinally applied field and is smaller in magnitude at ca. 116 T. Complex 3 behaves similarly to complex 1. They are sufficiently self-dilute (e.g., Fe···Fe distances of ca. 9-10 Å) to exhibit varying degrees of slow paramagnetic relaxation in zero field for the neat solid form. In the absence of EPR signals for 1-3, we show that heat-capacity measurements for one of the complexes (3) establish a geff value near 12, in agreement with the principal component of the ligand electric field gradient being coincident with the z axis.

AB - Mössbauer studies of three two-coordinate linear high-spin Fe2+ compounds, namely, Fe{N(SiMe3)(Dipp)}2 (1) (Dipp = C6H3-2,6-iPr2), Fe(OAr′)2 (2) [Ar′ = C6H3-2,6-(C6H3-2,6-iPr2)2], and Fe{C(SiMe3)3}2 (3), are presented. The complexes were characterized by zero- and applied-field Mössbauer spectroscopy (1-3), as well as zero- and applied-field heat-capacity measurements (3). As 1-3 are rigorously linear, the distortion(s) that might normally be expected in view of the Jahn-Teller theorem need not necessarily apply. We find that the resulting very large unquenched orbital angular momentum leads to what we believe to be the largest observed internal magnetic field to date in a high-spin iron(II) compound, specifically +162 T in 1. The latter field is strongly polarized along the directions of the external field for both longitudinal and transverse field applications. For the longitudinal case, the applied field increases the overall hyperfine splitting consistent with a dominant orbital contribution to the effective internal field. By contrast, 2 has an internal field that is not as strongly polarized along a longitudinally applied field and is smaller in magnitude at ca. 116 T. Complex 3 behaves similarly to complex 1. They are sufficiently self-dilute (e.g., Fe···Fe distances of ca. 9-10 Å) to exhibit varying degrees of slow paramagnetic relaxation in zero field for the neat solid form. In the absence of EPR signals for 1-3, we show that heat-capacity measurements for one of the complexes (3) establish a geff value near 12, in agreement with the principal component of the ligand electric field gradient being coincident with the z axis.

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