Staff View: Spin-Frustrated Complex, [FeIIFeIII(trans-1,4-cyclohexanedicarboxylate)1.5]∞: Interplay between Single-Chain Magnetic Behavior and Magnetic Ordering

Spin-Frustrated Complex, [FeIIFeIII(trans-1,4-cyclohexanedicarboxylate)1.5]∞: Interplay between Single-Chain Magnetic Behavior and Magnetic Ordering

A three-dimensional mixed-valent iron(II, III) trans-1,4- cyclohexanedicarboxylate, 1,4-chdc, coordination polymer, [Fe IIFe III-(μ4-O)(1,4-chdc) 1.5]∞, 1, has been synthesized hydrothermally by mixing iron powder and 1,4-chdcH 2 and investigated by X-ray diffraction, dc and ac magnetic susceptibili...

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Main Authors:	Zheng, Yan-Zhen, Xue, Wei, Zhang, Wei-Xiong, Tong, Ming-Liang, Chen, Xiao-Ming, Grandjean, Fernande, Long, Gary J., Ng, Seik Weng, Panissod, Pierre, Drillon, Marc
Format:	Article
Published:	American Chemical Society 2009
Subjects:	Q Science (General) QD Chemistry
Online Access:	http://eprints.um.edu.my/25092/ https://doi.org/10.1021/ic8019155
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spelling	my.um.eprints.250922020-07-13T08:22:42Z http://eprints.um.edu.my/25092/ Spin-Frustrated Complex, [FeIIFeIII(trans-1,4-cyclohexanedicarboxylate)1.5]∞: Interplay between Single-Chain Magnetic Behavior and Magnetic Ordering Zheng, Yan-Zhen Xue, Wei Zhang, Wei-Xiong Tong, Ming-Liang Chen, Xiao-Ming Grandjean, Fernande Long, Gary J. Ng, Seik Weng Panissod, Pierre Drillon, Marc Q Science (General) QD Chemistry A three-dimensional mixed-valent iron(II, III) trans-1,4- cyclohexanedicarboxylate, 1,4-chdc, coordination polymer, [Fe IIFe III-(μ4-O)(1,4-chdc) 1.5]∞, 1, has been synthesized hydrothermally by mixing iron powder and 1,4-chdcH 2 and investigated by X-ray diffraction, dc and ac magnetic susceptibility, and iron-57 Mössbauer spectroscopy over a wide range of temperatures. Single-crystal X-ray diffraction studies of 1 at 90(2), 293(2), and 473(2) K reveal a tetrahedral [Fe ll 2(μ 4-O)Fe lll 2(μ 4-O)] 6+ mixed-spin-chain structure with no change in the P1̄ space group but with subtle changes in the Fe-0 and Fe Fe distances with increasing temperature. These changes are associated with the electron delocalization observed by Mossbauer spectroscopy above 225 K. Magnetic studies reveal three different magnetic regimes in 1 between 2 and 320 K. Above 36 K 1 is a one-dimensional ferrimagnetic-like complex with frustration arising from competing exchange interactions between the iron(ll) and iron(lll) ions in the chains. Between 36 and 25 K the interchain interactions are non-negligible and 1 undergoes three-dimensional ordering at 32.16 K but with some residual fluctuations. Below 25 K the residual fluctuations slow and eventually freeze below 15 K.; the small net moment of 0.22 μ B per mole of 1 observed below 15 K may be attributed to a non-collinear or canted spin structure of the spins of the four iron ions in the [Fe II 2(μ 4-O)Fe lll 2-(μ 4-O)] 6+ chains. Below 32 K the Mössbauer spectra of 1 exhibit sharp sextets for both the iron(lll) and iron(ll) ions and are consistent with either a static long-range or a short-range magnetic ground state or a slow relaxation between two canted magnetic states that are indistinguishable at the observed spectral resolution. The 85 and 155 K spectra reveal no electron delocalization and correspond solely to fixed valence iron(ll) and iron(lll). Between 225 and 310 K the spectra reveal the onset of electron delocalization such that, at 295 to 310 K, 25, 25, and 50% of the iron in 1 is present as iron(ll), iron(lll), and iron(ll/lll) ions, respectively. The absence of any spectral line broadening associated with this electron delocalization and the coexistence of four doublets between 225 and 310 K indicate that the delocalization occurs through electron tunneling via vibronic coupling. The sudden increase in the tunneling rate beginning above about 260 K and the presence of a cusp in the magnetic susceptibility centered at about 275 K strongly suggest the existence of a charge order/disorder transition whose nature and order are discussed. © 2009 American Chemical Society. American Chemical Society 2009 Article PeerReviewed Zheng, Yan-Zhen and Xue, Wei and Zhang, Wei-Xiong and Tong, Ming-Liang and Chen, Xiao-Ming and Grandjean, Fernande and Long, Gary J. and Ng, Seik Weng and Panissod, Pierre and Drillon, Marc (2009) Spin-Frustrated Complex, [FeIIFeIII(trans-1,4-cyclohexanedicarboxylate)1.5]∞: Interplay between Single-Chain Magnetic Behavior and Magnetic Ordering. Inorganic Chemistry, 48 (5). pp. 2028-2042. ISSN 0020-1669 https://doi.org/10.1021/ic8019155 doi:10.1021/ic8019155
institution	Universiti Malaya
building	UM Library
collection	Institutional Repository
continent	Asia
country	Malaysia
content_provider	Universiti Malaya
content_source	UM Research Repository
url_provider	http://eprints.um.edu.my/
topic	Q Science (General) QD Chemistry
spellingShingle	Q Science (General) QD Chemistry Zheng, Yan-Zhen Xue, Wei Zhang, Wei-Xiong Tong, Ming-Liang Chen, Xiao-Ming Grandjean, Fernande Long, Gary J. Ng, Seik Weng Panissod, Pierre Drillon, Marc Spin-Frustrated Complex, [FeIIFeIII(trans-1,4-cyclohexanedicarboxylate)1.5]∞: Interplay between Single-Chain Magnetic Behavior and Magnetic Ordering
description	A three-dimensional mixed-valent iron(II, III) trans-1,4- cyclohexanedicarboxylate, 1,4-chdc, coordination polymer, [Fe IIFe III-(μ4-O)(1,4-chdc) 1.5]∞, 1, has been synthesized hydrothermally by mixing iron powder and 1,4-chdcH 2 and investigated by X-ray diffraction, dc and ac magnetic susceptibility, and iron-57 Mössbauer spectroscopy over a wide range of temperatures. Single-crystal X-ray diffraction studies of 1 at 90(2), 293(2), and 473(2) K reveal a tetrahedral [Fe ll 2(μ 4-O)Fe lll 2(μ 4-O)] 6+ mixed-spin-chain structure with no change in the P1̄ space group but with subtle changes in the Fe-0 and Fe Fe distances with increasing temperature. These changes are associated with the electron delocalization observed by Mossbauer spectroscopy above 225 K. Magnetic studies reveal three different magnetic regimes in 1 between 2 and 320 K. Above 36 K 1 is a one-dimensional ferrimagnetic-like complex with frustration arising from competing exchange interactions between the iron(ll) and iron(lll) ions in the chains. Between 36 and 25 K the interchain interactions are non-negligible and 1 undergoes three-dimensional ordering at 32.16 K but with some residual fluctuations. Below 25 K the residual fluctuations slow and eventually freeze below 15 K.; the small net moment of 0.22 μ B per mole of 1 observed below 15 K may be attributed to a non-collinear or canted spin structure of the spins of the four iron ions in the [Fe II 2(μ 4-O)Fe lll 2-(μ 4-O)] 6+ chains. Below 32 K the Mössbauer spectra of 1 exhibit sharp sextets for both the iron(lll) and iron(ll) ions and are consistent with either a static long-range or a short-range magnetic ground state or a slow relaxation between two canted magnetic states that are indistinguishable at the observed spectral resolution. The 85 and 155 K spectra reveal no electron delocalization and correspond solely to fixed valence iron(ll) and iron(lll). Between 225 and 310 K the spectra reveal the onset of electron delocalization such that, at 295 to 310 K, 25, 25, and 50% of the iron in 1 is present as iron(ll), iron(lll), and iron(ll/lll) ions, respectively. The absence of any spectral line broadening associated with this electron delocalization and the coexistence of four doublets between 225 and 310 K indicate that the delocalization occurs through electron tunneling via vibronic coupling. The sudden increase in the tunneling rate beginning above about 260 K and the presence of a cusp in the magnetic susceptibility centered at about 275 K strongly suggest the existence of a charge order/disorder transition whose nature and order are discussed. © 2009 American Chemical Society.
format	Article
author	Zheng, Yan-Zhen Xue, Wei Zhang, Wei-Xiong Tong, Ming-Liang Chen, Xiao-Ming Grandjean, Fernande Long, Gary J. Ng, Seik Weng Panissod, Pierre Drillon, Marc
author_facet	Zheng, Yan-Zhen Xue, Wei Zhang, Wei-Xiong Tong, Ming-Liang Chen, Xiao-Ming Grandjean, Fernande Long, Gary J. Ng, Seik Weng Panissod, Pierre Drillon, Marc
author_sort	Zheng, Yan-Zhen
title	Spin-Frustrated Complex, [FeIIFeIII(trans-1,4-cyclohexanedicarboxylate)1.5]∞: Interplay between Single-Chain Magnetic Behavior and Magnetic Ordering
title_short	Spin-Frustrated Complex, [FeIIFeIII(trans-1,4-cyclohexanedicarboxylate)1.5]∞: Interplay between Single-Chain Magnetic Behavior and Magnetic Ordering
title_full	Spin-Frustrated Complex, [FeIIFeIII(trans-1,4-cyclohexanedicarboxylate)1.5]∞: Interplay between Single-Chain Magnetic Behavior and Magnetic Ordering
title_fullStr	Spin-Frustrated Complex, [FeIIFeIII(trans-1,4-cyclohexanedicarboxylate)1.5]∞: Interplay between Single-Chain Magnetic Behavior and Magnetic Ordering
title_full_unstemmed	Spin-Frustrated Complex, [FeIIFeIII(trans-1,4-cyclohexanedicarboxylate)1.5]∞: Interplay between Single-Chain Magnetic Behavior and Magnetic Ordering
title_sort	spin-frustrated complex, [feiifeiii(trans-1,4-cyclohexanedicarboxylate)1.5]∞: interplay between single-chain magnetic behavior and magnetic ordering
publisher	American Chemical Society
publishDate	2009
url	http://eprints.um.edu.my/25092/ https://doi.org/10.1021/ic8019155
_version_	1680856998916128768
score	13.211869

Spin-Frustrated Complex, [FeIIFeIII(trans-1,4-cyclohexanedicarboxylate)1.5]∞: Interplay between Single-Chain Magnetic Behavior and Magnetic Ordering

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