TY - JOUR
T1 - 2D Conductive Iron-Quinoid Magnets Ordering up to Tc = 105 K via Heterogenous Redox Chemistry
AU - DeGayner, Jordan A.
AU - Jeon, Ie Rang
AU - Sun, Lei
AU - Dincă, Mircea
AU - Harris, T. David
N1 - Funding Information:
Work in the Harris lab (J.A.D., I.R.J., and T.D.H.) was supported by the National Science Foundation through Grant DMR-1351959 and Northwestern University. T.D.H. thanks the Alfred P. Sloan Foundation. Work in the Dincă lab (L.S. and M.D.) was supported as part of the Center for Excitonics, an Energy Frontier Research Center funded by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under award no. DE-SC0001088 (MIT). M.D. gratefully acknowledges early career support from the Sloan Foundation, the Research Corporation for Science Advancement (Cottrell Scholar), and the Dreyfus Foundation. Purchase of the SQUID magnetometer was supported in part by the International Institute of Nanotechnology. Use of the Advanced Photon Source at Argonne National Laboratory was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The X-ray crystallography made use of the Integrated Molecular Structure Education and Research Center (IMSERC) at Northwestern University, with support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF NNCI-1542205), the State of Illinois, and International Institute for Nanotechnology (IIN). Raman spectroscropy was performed at the SPID facility of Northwestern University’s NUANCE Center, with support from the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (NSF ECCS-1542205); the MRSEC program (NSF DMR-1121262) at the Materials Research Center; the International Institute for Nanotechnology (IIN); the Keck Foundation; and the State of Illinois, through the IIN. Metals analysis was performed at the Northwestern University Quantitative Bioelement Imaging Center. We thank Dr. C. D. Malliakas, Ms. Y. Wang, and Mr. A. Banisafar for experimental assistance.
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/3/22
Y1 - 2017/3/22
N2 - We report the magnetism and conductivity for a redox pair of iron-quinoid metal-organic frameworks (MOFs). The oxidized compound, (Me2NH2)2[Fe2L3]·2H2O·6DMF (LH2 = 2,5-dichloro-3,6-dihydroxo-1,4-benzoquinone) was previously shown to magnetically order below 80 K in its solvated form, with the ordering temperature decreasing to 26 K upon desolvation. Here, we demonstrate this compound to exhibit electrical conductivity values up to σ = 1.4(7) × 10-2 S/cm (Ea = 0.26(1) cm-1) and 1.0(3) × 10-3 S/cm (Ea = 0.19(1) cm-1) in its solvated and desolvated forms, respectively. Upon soaking in a DMF solution of Cp2Co, the compound undergoes a single-crystal-to-single-crystal one-electron reduction to give (Cp2Co)1.43(Me2NH2)1.57[Fe2L3]·4.9DMF. Structural and spectroscopic analysis confirms this reduction to be ligand-based, and as such the trianionic framework is formulated as [FeIII2(L3-•)3]3-. Magnetic measurements for this reduced compound reveal the presence of dominant intralayer metal-organic radical coupling to give a magnetically ordered phase below Tc = 105 K, one of the highest reported ordering temperatures for a MOF. This high ordering temperature is significantly increased relative to the oxidized compound, and stems from the overall increase in coupling strength afforded by an additional organic radical. In line with the high critical temperature, the new MOF exhibits magnetic hysteresis up to 100 K, as revealed by variable-field measurements. Finally, this compound is electrically conductive, with values up to σ = 5.1(3) × 10-4 S/cm with Ea = 0.34(1) eV. Taken together, these results demonstrate the unique ability of metal-quinoid MOFs to simultaneously exhibit both high magnetic ordering temperatures and high electrical conductivity.
AB - We report the magnetism and conductivity for a redox pair of iron-quinoid metal-organic frameworks (MOFs). The oxidized compound, (Me2NH2)2[Fe2L3]·2H2O·6DMF (LH2 = 2,5-dichloro-3,6-dihydroxo-1,4-benzoquinone) was previously shown to magnetically order below 80 K in its solvated form, with the ordering temperature decreasing to 26 K upon desolvation. Here, we demonstrate this compound to exhibit electrical conductivity values up to σ = 1.4(7) × 10-2 S/cm (Ea = 0.26(1) cm-1) and 1.0(3) × 10-3 S/cm (Ea = 0.19(1) cm-1) in its solvated and desolvated forms, respectively. Upon soaking in a DMF solution of Cp2Co, the compound undergoes a single-crystal-to-single-crystal one-electron reduction to give (Cp2Co)1.43(Me2NH2)1.57[Fe2L3]·4.9DMF. Structural and spectroscopic analysis confirms this reduction to be ligand-based, and as such the trianionic framework is formulated as [FeIII2(L3-•)3]3-. Magnetic measurements for this reduced compound reveal the presence of dominant intralayer metal-organic radical coupling to give a magnetically ordered phase below Tc = 105 K, one of the highest reported ordering temperatures for a MOF. This high ordering temperature is significantly increased relative to the oxidized compound, and stems from the overall increase in coupling strength afforded by an additional organic radical. In line with the high critical temperature, the new MOF exhibits magnetic hysteresis up to 100 K, as revealed by variable-field measurements. Finally, this compound is electrically conductive, with values up to σ = 5.1(3) × 10-4 S/cm with Ea = 0.34(1) eV. Taken together, these results demonstrate the unique ability of metal-quinoid MOFs to simultaneously exhibit both high magnetic ordering temperatures and high electrical conductivity.
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U2 - 10.1021/jacs.7b00705
DO - 10.1021/jacs.7b00705
M3 - Article
C2 - 28230984
AN - SCOPUS:85015827560
VL - 139
SP - 4175
EP - 4184
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 11
ER -