Molecular spin frustration in mixed-chelate Fe5 and Fe6 oxo clusters with high ground state spin values

Alok P. Singh; Rajendra P. Joshi; Khalil A. Abboud; Juan E. Peralta; George Christou

doi:10.1016/j.poly.2019.114182

Molecular spin frustration in mixed-chelate Fe₅ and Fe₆ oxo clusters with high ground state spin values

Alok P. Singh, Rajendra P. Joshi, Khalil A. Abboud, Juan E. Peralta, George Christou

Physics

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

The synthesis, structures, and magnetic properties are reported of three new polynuclear Fe^III complexes containing the anions of picolinic acid (picH) and triethanolamine (teaH₃) as chelates. The complexes [Fe₆O₂(OH)₂(O₂CR)₄(pic)₄(teaH)₂] (R = Me (1), Ph (2)) and [Fe₅O₂(O₂CBu^t)₄(pic)₃(teaH)₂] (3) were obtained from the reaction of [Fe₃O(O₂CR)₆(H₂O)₃](NO₃) (R = Me, Ph, Bu^t) with picH and teaH₃ in a 1:2:1 ratio in MeCN. The core of 1 and 2 consists of an [Fe₄(µ₃-O)₂]⁸⁺ ‘planar-butterfly’ unit to which is attached an Fe atom on either side by bridging O atoms. The core of 3 consists of an [Fe₅(µ₃-O)₂]¹¹⁺ unit comprising two near-perpendicular vertex-sharing [Fe₃(µ₃-O)]⁷⁺ triangular units. Variable-temperature (T) and -field (H) solid-state dc and ac magnetization (M) studies in the 5.0–300 K temperature range revealed that 1 and 2 have an S = 5 ground state spin whereas 3 has an S = ⁵/₂ ground state. J_ij exchange couplings were calculated by DFT and a magnetostructural correlation (MSC) for polynuclear Fe^III/O complexes. This allowed rationalization of the observed ground states from the analysis of the spin frustration effects operative, and provided good input values for fits of the experimental χ_MT vs T data to obtain the J_ij values.

Original language	English
Article number	114182
Journal	Polyhedron
Volume	176
DOIs	https://doi.org/10.1016/j.poly.2019.114182
State	Published - Jan 15 2020

Keywords

Cluster
Crystal structure
DFT
Iron
Magnetic properties

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10.1016/j.poly.2019.114182

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@article{f145ceb3205c4af280312b6e392a1951,

title = "Molecular spin frustration in mixed-chelate Fe5 and Fe6 oxo clusters with high ground state spin values",

abstract = "The synthesis, structures, and magnetic properties are reported of three new polynuclear FeIII complexes containing the anions of picolinic acid (picH) and triethanolamine (teaH3) as chelates. The complexes [Fe6O2(OH)2(O2CR)4(pic)4(teaH)2] (R = Me (1), Ph (2)) and [Fe5O2(O2CBut)4(pic)3(teaH)2] (3) were obtained from the reaction of [Fe3O(O2CR)6(H2O)3](NO3) (R = Me, Ph, But) with picH and teaH3 in a 1:2:1 ratio in MeCN. The core of 1 and 2 consists of an [Fe4(µ3-O)2]8+ {\textquoteleft}planar-butterfly{\textquoteright} unit to which is attached an Fe atom on either side by bridging O atoms. The core of 3 consists of an [Fe5(µ3-O)2]11+ unit comprising two near-perpendicular vertex-sharing [Fe3(µ3-O)]7+ triangular units. Variable-temperature (T) and -field (H) solid-state dc and ac magnetization (M) studies in the 5.0–300 K temperature range revealed that 1 and 2 have an S = 5 ground state spin whereas 3 has an S = 5/2 ground state. Jij exchange couplings were calculated by DFT and a magnetostructural correlation (MSC) for polynuclear FeIII/O complexes. This allowed rationalization of the observed ground states from the analysis of the spin frustration effects operative, and provided good input values for fits of the experimental χMT vs T data to obtain the Jij values.",

keywords = "Cluster, Crystal structure, DFT, Iron, Magnetic properties",

author = "Singh, {Alok P.} and Joshi, {Rajendra P.} and Abboud, {Khalil A.} and Peralta, {Juan E.} and George Christou",

note = "Funding Information: This work was supported by the U.S. Department of Energy , Office of Science , Office of Basic Energy Sciences , as part of the Computational Chemical Sciences Program under Award #DE-SC0018331. Appendix A Publisher Copyright: {\textcopyright} 2019",

year = "2020",

month = jan,

day = "15",

doi = "10.1016/j.poly.2019.114182",

language = "English",

volume = "176",

journal = "Polyhedron",

issn = "0277-5387",

publisher = "Polyhedron",

}

TY - JOUR

T1 - Molecular spin frustration in mixed-chelate Fe5 and Fe6 oxo clusters with high ground state spin values

AU - Singh, Alok P.

AU - Joshi, Rajendra P.

AU - Abboud, Khalil A.

AU - Peralta, Juan E.

AU - Christou, George

N1 - Funding Information: This work was supported by the U.S. Department of Energy , Office of Science , Office of Basic Energy Sciences , as part of the Computational Chemical Sciences Program under Award #DE-SC0018331. Appendix A Publisher Copyright: © 2019

PY - 2020/1/15

Y1 - 2020/1/15

N2 - The synthesis, structures, and magnetic properties are reported of three new polynuclear FeIII complexes containing the anions of picolinic acid (picH) and triethanolamine (teaH3) as chelates. The complexes [Fe6O2(OH)2(O2CR)4(pic)4(teaH)2] (R = Me (1), Ph (2)) and [Fe5O2(O2CBut)4(pic)3(teaH)2] (3) were obtained from the reaction of [Fe3O(O2CR)6(H2O)3](NO3) (R = Me, Ph, But) with picH and teaH3 in a 1:2:1 ratio in MeCN. The core of 1 and 2 consists of an [Fe4(µ3-O)2]8+ ‘planar-butterfly’ unit to which is attached an Fe atom on either side by bridging O atoms. The core of 3 consists of an [Fe5(µ3-O)2]11+ unit comprising two near-perpendicular vertex-sharing [Fe3(µ3-O)]7+ triangular units. Variable-temperature (T) and -field (H) solid-state dc and ac magnetization (M) studies in the 5.0–300 K temperature range revealed that 1 and 2 have an S = 5 ground state spin whereas 3 has an S = 5/2 ground state. Jij exchange couplings were calculated by DFT and a magnetostructural correlation (MSC) for polynuclear FeIII/O complexes. This allowed rationalization of the observed ground states from the analysis of the spin frustration effects operative, and provided good input values for fits of the experimental χMT vs T data to obtain the Jij values.

AB - The synthesis, structures, and magnetic properties are reported of three new polynuclear FeIII complexes containing the anions of picolinic acid (picH) and triethanolamine (teaH3) as chelates. The complexes [Fe6O2(OH)2(O2CR)4(pic)4(teaH)2] (R = Me (1), Ph (2)) and [Fe5O2(O2CBut)4(pic)3(teaH)2] (3) were obtained from the reaction of [Fe3O(O2CR)6(H2O)3](NO3) (R = Me, Ph, But) with picH and teaH3 in a 1:2:1 ratio in MeCN. The core of 1 and 2 consists of an [Fe4(µ3-O)2]8+ ‘planar-butterfly’ unit to which is attached an Fe atom on either side by bridging O atoms. The core of 3 consists of an [Fe5(µ3-O)2]11+ unit comprising two near-perpendicular vertex-sharing [Fe3(µ3-O)]7+ triangular units. Variable-temperature (T) and -field (H) solid-state dc and ac magnetization (M) studies in the 5.0–300 K temperature range revealed that 1 and 2 have an S = 5 ground state spin whereas 3 has an S = 5/2 ground state. Jij exchange couplings were calculated by DFT and a magnetostructural correlation (MSC) for polynuclear FeIII/O complexes. This allowed rationalization of the observed ground states from the analysis of the spin frustration effects operative, and provided good input values for fits of the experimental χMT vs T data to obtain the Jij values.

KW - Cluster

KW - Crystal structure

KW - DFT

KW - Iron

KW - Magnetic properties

UR - http://www.scopus.com/inward/record.url?scp=85075397684&partnerID=8YFLogxK

U2 - 10.1016/j.poly.2019.114182

DO - 10.1016/j.poly.2019.114182

M3 - Article

AN - SCOPUS:85075397684

SN - 0277-5387

VL - 176

JO - Polyhedron

JF - Polyhedron

M1 - 114182

ER -

Molecular spin frustration in mixed-chelate Fe₅ and Fe₆ oxo clusters with high ground state spin values

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