V) Ferromagnet

Article pubs.acs.org/crystal

Mixed-Valence Cobalt(II/III)−Octacyanidotungstate(IV/V) Ferromagnet Keiko Komori-Orisaku,†,‡ Kenta Imoto,† Yoshihiro Koide,‡ and Shin-ichi Ohkoshi*,†,§ †

Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan Department of Material Life Chemistry, Faculty of Engineering, Kanagawa University, 3-27-1 Rokkaku-bashi, Kanagawa-ku, Yokohama, Kanagawa, 221-8686 Japan § Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi, Saitama, 332-0012, Japan ‡

S Supporting Information *

ABSTRACT: We report a mixed-valence cobalt(II/III)− octacyanidotungstate(IV/V) magnet, [CoII(H2O)]2[CoIII{μ(R)-1-(4-pyridyl)ethanol}2][WIV(CN)8][WV(CN)8]·5H2O. Synchrotron-radiation X-ray single crystal structural analysis, infrared spectrum, and density-functional theory (DFT) calculation indicate that this compound has a chiral structure with the P21 space group and both CoII(S = 3/2)−NC−WV(S = 1/2) and CoIII(S = 0)−NC−WIV(S = 0) moieties, which are structurally distinguishable in the crystal structure. Magnetic measurements reveal that this compound exhibits ferromagnetism with a Curie temperature of 11 K and a coercive field of 1500 Oe, which is caused by the coexistence of the superexchange interaction in the CoII−WV chain and double exchange interaction between the chains.

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mmol) to a mixed aqueous solution (5 cm3) of CoCl2·6H2O (65 mg, 0.27 mmol) and (R)-1-(4-pyridyl)ethanol (22.4 mg, 0.18 mmol) with slow stirring. After 7 days of stirring, the precipitated brown powder was filtered and washed with water and then dried in air. Elemental analyses indicate that the formula of the compound is [Co{(R)-1-(4pyridyl)ethanol}2][Co(H2O)]2[W(CN)8]2·5H2O. Yield: 89.7 mg (74.3%). Calcd: Co, 13.3; W, 27.6; C, 27.0; H, 2.4; N, 18.9%. Found: Co, 13.5; W, 27.6; C, 26.7; H, 2.5; N, 18.7%. Synchrotron-Radiation X-ray Single Crystal Structural Analysis. The single crystals were obtained from the filtrate of the mixed solution stirred for 1 day by evaporating slowly for 4 weeks at room temperature. The size of the crystals was small, ca. 0.01 × 0.01 × 0.01 mm3 (Figure S1, Supporting Information). We used synchrotron radiation at SPring-8 synchrotron facility. X-ray diffraction data were collected at BL38B1 (beam size = 142.0 × 87.0 μm2, wavelength = 0.75 Å) with a CCD detector (ADSC/Quantum315r). Diffraction data were processed by the CrystalClear package. The crystal structure was solved by direct methods (SIR 2004) and refined by full-matrix leastsquares methods on F2 using SHELXL-97 (Table 1).7 Physical Measurements. The infrared (IR) spectrum was recorded on JASCO FT/IR-4100 spectrometer. The magnetic properties were measured by a superconducting quantum interference device (SQUID) magnetometer (Quantum design MPMS5 or MPMS7). Computational Details. Unrestricted density-functional theory (DFT/B3LYP) calculations were carried out with the Gaussian 09

INTRODUCTION Cyanido-bridged bimetal assemblies are aggressively studied as external-stimuli-responsive material.1 Especially in mixedvalence cyanido-bridged metal assemblies, the physical properties are expected to be controlled by the external stimuli.2−6 For example, Rb0.88Mn[Fe(CN)6]0.96, a hexacyanidometalate-based magnet, exhibits temperature- and photoinduced phase transition between MnII−FeIII phase and MnIII−FeII phase.3 Bistability of valence isomers is significant in such a chargetransfer phase transition material. From this angle, octacyanidometalates [M(CN)8] (M = Mo, W, and Nb) are attractive building blocks because [M(CN)8] have multiple valence states, for example, MoIV/V and WIV/V, and various coordination geometries.4 To date, several functional mixed-valence, molecule-based magnets based on [M(CN)8], such as Cu I I 2 [Mo I V (CN) 8 ]·8H 2 O and [Co I I (pyrimidine) 2 ] 2 [CoII(H 2O) 2][WV (CN) 8]2·4H2O, have been reported.5,6 These materials exhibit photoinduced phase transition due to charge transfer. In this paper, we report a mixed-valence Co−W cyanido-bridged assembly [CoII(H2O)]2[CoIII{μ-(R)-1-(4pyridyl)ethanol}2][WIV(CN)8][WV(CN)8]·5H2O, which has both CoII(S = 3/2)−NC−WV(S = 1/2) and CoIII(S = 0)− NC−WIV(S = 0) moieties in the structure and exhibits ferromagnetism with a Curie temperature (TC) of 11 K.

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EXPERIMENTAL SECTION

Received: July 5, 2013 Revised: October 5, 2013 Published: October 18, 2013

Synthesis. The target compound was prepared by adding an aqueous solution (5 cm3) of Cs3[W(CN)8]·2H2O (150 mg, 0.18 © 2013 American Chemical Society

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dx.doi.org/10.1021/cg401011d | Cryst. Growth Des. 2013, 13, 5267−5271

Crystal Growth & Design

Article

centers are pseudo-octahedron. The four equatorial positions of Co1 and Co2 are occupied by four cyanido nitrogen atoms of [W(CN)8], and two apical positions are occupied by an oxygen atom of a coordinated water molecule and a hydroxyl oxygen atom of an (R)-1-(4-pyridyl)ethanol molecule. The four equatorial positions of six-coordinated Co3 are also occupied by cyanido nitrogen atoms of [W(CN)8], while the two apical positions are occupied by nitrogen atoms of the pyridine rings. The coordination geometries of [W1(CN)8] and [W2(CN)8] are square face bicapped trigonal prisms (Figure 2, Tables S1

Table 1. Crystallographic Data from Single-Crystal X-ray Analysis radiation type wavelength, Å cryst size, mm3 empirical formula formula wt cryst syst space group T, K a, Å b, Å c, Å β, deg V, Å3 μ, mm−1 Z dcalcd, g cm−3 no. of data/params GOF on F2 R/wR2 [I > 2σ(I)]

synchrotron (SPring-8, BL38B1) 0.75 0.01 × 0.01 × 0.01 C30H28Co3N18O7W2 1297.19 monoclinic P21 (No. 4) 100(2) 7.2123(5) 24.0547(18) 11.7186(8) 90.042(2) 2033.1(2) 6.903 2 2.116 14024/555 1.026 0.0932/0.2858

program.8 The geometries of [WIV(CN)8]4− and [WV(CN)8]3− were optimized using 6-31+G(d) basis set for C and N atoms and lanL2DZ basis set, including Los Alamos effective core potentials,9 for W atoms. Based on the crystal structure of the present compound, DFT calculations were performed under the condition that Opt=Z-Matrix was utilized with C2v symmetry, since the coordination geometry of [W(CN)8] is nearest to a square face bicapped trigonal prism (C2v symmetry).

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RESULTS AND DISCUSSION Crystal Structure. The synchrotron-radiation X-ray single crystal structural analysis shows that the present compound has the P21 space group. The asymmetric unit is composed of a [Co{(R)-1-(4-pyridyl)ethanol}2] cation, two [Co(H2O)] cations, two [W(CN)8] anions, and five noncoordinated water molecules (Figure 1). The coordination geometries of Co

Figure 2. Coordination geometries and bond distances around metal centers, where di−j represents average bond distances between atoms i and j.

and S2, Supporting Information). Two square face capped positions of W1 and W2 are coordinated by C atoms of nonbridged CN ligands. The crystal structure from three directions is shown in Figure 3a−c. The three Co atoms are connected linearly with the bridging (R)-1-(4-pyridyl)ethanol molecules along the bc plane, and then the W atoms are bound with Co(NC)4 moieties to form a three-dimensional chiral network. Two (R)-1-(4-pyridyl)ethanol molecules bridged to Co1 and Co2 are parallel to each other in the head-to-tail fashion, in which methyl groups are directed toward the pyridine rings. The electric polarization is along the b-axis (2fold screw axis) (Figure 3d). Valence States of Metal Centers. The Co1−N bond distances (dCo1−N) around the Co1 center are between 2.07 and 2.13 Å (2.11 Å on average), while Co2−N bond distances (dCo2−N) around Co2 centers are between 2.05 and 2.10 Å (2.07 Å on average). The six Co3−N bond distances (dCo3−N) are between 1.86 and 1.98 Å (1.91 Å on average) (Tables S1

Figure 1. The coordination environments around W and Co. Displacement ellipsoids are drawn at a 50% probability level. Blue, magenta, gray, pale blue, pale pink, and green spheres represent W, Co, C, N, O, and H atoms, respectively. The average bond distances between atoms i and j are denoted by di−j. Hydrogen atoms (except for the hydrogen atoms around the chiral atoms), noncoordinated water molecules, and disordered atoms are omitted for clarity. 5268



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Figure 3. (a) The crystal structure along the a-axis. Displacement ellipsoids are drawn at a 30% probability level. Blue, magenta, gray, light blue, orange, and green spheres represent W, Co, C, N, O, and H atoms, respectively. Hydrogen atoms (except for those around the chiral atoms), noncoordinated water molecules, and disordered atoms are omitted for clarity. (b) Crystal structure along the b-axis. (c) Crystal structure along the c-axis. (d) The enlarged view of the chiral molecules aligned along the 2-fold screw axis, which is represented by a red line.

and S2, Supporting Information). Comparing the average Co− N bond distances to those of the reported [CoIII(phen)(CN)4]2[CoII(phen)2] complex (phen = 1,10-phenantroline)10 shows that the average dCo1−N (2.11 Å) and dCo2−N (2.07 Å) bond distances are similar to the average CoII−N(phen) bond distance of 2.15 Å, while the average dCo3−N (1.91 Å) bond distance is similar to the CoIII−N(phen) bond distance of 1.97 Å. These results indicate that the valence states of Co1 and Co2 are II and that of Co3 is III. The bond distances between W and C atoms of nonbridged CN ligands are 2.24 and 2.27 Å for W1 and 2.08 and 2.10 Å for W2. The other six positions of W1 and W2 are coordinated by C atoms of bridged CN ligands with the average W1−C and W2−C distances of 2.15 and 2.10 Å, respectively. The W1−C bond distances for each position are longer than W2−C bond distances, indicating that the valence states of W1 and W2 are IV and V, respectively. The bond distances of [WIV(CN)8] and [WV(CN)8] were estimated by unrestricted DFT(B3LYP) calculations using the Gaussian 09 program8 (Figure S4, Supporting Information). As a result, the optimized W−C distance of WV−C was shorter than that of WIV−C, supporting the valence states of WIV and WV for W1

and W2 sites, respectively. From these results, the electronic states are assigned to be [CoII(H2O)]2[CoIII{(R)-1-(4-pyridyl)ethanol)}2][WV(CN)8][WIV(CN)8]·5H2O. The IR spectrum of this compound (Figure S5, Supporting Information) also supports the proposed valence states as follows: the weak absorption band at 2185 cm−1 is assigned to the CN stretching mode of WV−CN, while the strong absorption band at 2152 cm−1 is attributed to the CN stretching mode of WIV−CN. In addition, the results of X-ray photoelectron spectroscopy (XPS) also indicated the coexistence of WV and WIV (Figure S6, Supporting Information). Magnetic Properties. The field-cooled magnetization (FCM) curve under the external magnetic field of 10 Oe exhibited a spontaneous magnetization at Tc of 11 K, which is determined by extrapolating the straight line in the FCM curve (Figure 4). The zero-field-cooled magnetization (ZFCM) and remnant magnetization (RM) curves supported the observed TC value. The magnetization vs external magnetic field plot at 2 K showed a hysteresis loop with a coercive field (Hc) of 1500 Oe and saturation magnetization (Ms) of 5.4 μB (under 7 T). Considering the ground Kramer’s doublet of an octahedral 5269



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Figure 4. Field-cooled magnetization (FCM, ●) and zero-field-cooled magnetization (ZFCM, ○) curves in an external applied field of 10 Oe, and remnant magnetization (RM, Δ) curve. The inset shows a magnetic hysteresis loop at 2 K.

CoII, the magnetic moment of CoII is (13/6) μB (gCoJCo = (13/ 3) × (1/2)). The magnetic moment of WV, however, is 1 μB (gWJW = 2 × (1/2)). Hence, the estimated Ms value for ferromagnetic ordering according to the system mentioned above is 5.3 μB, which is consistent with the observed Ms value. The origin of the ferromagnetic ordering of the present compound is considered to be the following. The cyanidobridged −CoII1(S = 3/2)−NC−WV2(S = 1/2)−CN−CoII2(S = 3/2)− network forms a one-dimensional superexchange pathway along the a-axis. It is known that a one-dimensional magnetic chain does not exhibit a magnetic phase transition. This knowledge is inconsistent with the ferromagnetic ordering in the present compound, and hence a higher-dimensional magnetic network should be considered. Based on the fact that the present compound has mixed valence, the possibility of a ferromagnetic double exchange interaction also exists, as shown in Figure 5. If so, a three-dimensional ferromagnetic network is formed due to both the superexchange and the double exchange interactions, such that ferromagnetic ordering is observed.

Figure 5. (a) Schematic diagram of a three-dimensional ferromagnetic network along the b-axis formed due to both superexchange and double exchange interactions. Orange and blue parts show superexchange and double exchange interactions, respectively. (b) A threedimensional ferromagnetic network in the crystal structure along aaxis.

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ASSOCIATED CONTENT

* Supporting Information S

Photograph of the crystal used for single-crystal X-ray analysis, crystallographic data from single-crystal X-ray analysis, coordination environments and crystal structures, XRD patterns, DFT calculation using Gaussian 09 software, IR spectrum, and XPS analysis. This material is available free of charge via the Internet at http://pubs.acs.org.

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CONCLUSION In this study, we synthesized a mixed-valence Co−W cyanidobridged magnet, [CoII(H2O)]2[CoIII{μ-(R)-1-(4-pyridyl)ethanol}2][WIV(CN)8][WV(CN)8]·5H2O, in which the valence state of each metal site is structurally distinguishable. This compound is a chiral structural ferromagnet with TC = 11 K. The present system possesses both paramagnetic CoII(S = 3/ 2)−NC−WV(S = 1/2) and diamagnetic CoIII(S = 0)−NC− WIV(S = 0) moieties in the crystal structure, which is promising for bidirectional phase transitions induced by external stimuli, for example, light or pressure. Although the origin of the mixed valence of the present compound is not clear at present, the following points are different between the present compound, [Co{(R)-1-(4-pyridyl)ethanol} 2 ][Co(H 2 O)] 2 [W(CN) 8 ] 2 · 5H2O, and the previous compound, [CoII(pyrimidine)2]2[CoII(H2O)2][WV(CN)8]2·4H2O, in ref 6a. The numbers of organic ligand are 2 and 4 for the present compound and the previous compound, respectively, and the numbers of bridging CN ligands around W sites are 6 and 5, respectively. Such differences in coordination may lead to coexistence of CoII−WV and CoIII−WIV.

AUTHOR INFORMATION

Corresponding Author

*Tel: +81-3-5841-4331. Fax: +81-3-3812-1896. E-mail: [email protected]. Web: http://www.chem.s.utokyo.ac.jp/users/ssphys/english/index.html. Author Contributions

The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS The synchrotron radiation experiments were performed at the BL38B1 of SPring-8, with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal No. 2011A1059). We are grateful to Dr. K. Nakabayashi for helpful discussions. This research is supported in part by the Core Research for Evolutional Science and Technology 5270



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270−277. (d) Bleuzen, A.; Marvaud, V.; Mathonière, C.; Sieklucka, B.; Verdaguer, M. Inorg. Chem. 2009, 48, 3453−3466. (6) (a) Ohkoshi, S.; Ikeda, S.; Hozumi, T.; Kashiwagi, T.; Hashimoto, K. J. Am. Chem. Soc. 2006, 128, 5320−5321. (b) Ohkoshi, S.; Hamada, Y.; Matsuda, T.; Tunobuchi, Y.; Tokoro, H. Chem. Mater. 2008, 20, 3048−3054. (c) Mahfoud, T.; Molnár, G.; Bonhommeau, S.; Cobo, S.; Salmon, L.; Demont, P.; Tokoro, H.; Ohkoshi, S.; Boukheddaden, K.; Bousseksou, A. J. Am. Chem. Soc. 2009, 131, 15049−15054. (d) Le Bris, R.; Tsunobuchi, Y.; Mathonière, C.; Tokoro, H.; Ohkoshi, S.; Ould-Moussa, N.; Molnar, G.; Bousseksou, A.; Létard, J.-F. Inorg. Chem. 2012, 51, 2852−2859. (7) Sheldrick, G. M. Acta Crystallogr. A 2008, 64, 112−122. (8) Frisch, M. J.; Trucks, G. W.; Schlegel, H. B.; Scuseria, G. E.; Robb, M. A.; Cheeseman, J. R.; Scalmani, G.; Barone, V.; Mennucci, B.; Petersson, G. A.; Nakatsuji, H.; Caricato, M.; Li, X.; Hratchian, H. P.; Izmaylov, A. F.; Bloino, J.; Zheng, G.; Sonnenberg, J. L.; Hada, M.; Ehara, M.; Toyota, K.; Fukuda, R.; Hasegawa, J.; Ishida, M.; Nakajima, T.; Honda, Y.; Kitao, O.; Nakai, H.; Vreven, T.; Montgomery, J. A., Jr.; Peralta, J. E.; Ogliaro, F.; Bearpark, M.; Heyd, J. J.; Brothers, E.; Kudin, K. N.; Staroverov, V. N.; Kobayashi, R.; Normand, J.; Raghavachari, K.; Rendell, A.; Burant, J. C.; Iyengar, S. S.; Tomasi, J.; Cossi, M.; Rega, N.; Millam, J. M.; Klene, M.; Knox, J. E.; Cross, J. B.; Bakken, V.; Adamo, C.; Jaramillo, J.; Gomperts, R.; Stratmann, R. E.; Yazyev, O.; Austin, A. J.; Cammi, R.; Pomelli, C.; Ochterski, J. W.; Martin, R. L.; Morokuma, K.; Zakrzewski, V. G.; Voth, G. A.; Salvador, P.; Dannenberg, J. J.; Dapprich, S.; Daniels, A. D.; Farkas, O.; Foresman, J. B.; Ortiz, J. V.; Cioslowski, J.; Fox, D. J. Gaussian 09, revision A.02; Gaussian, Inc.: Wallingford, CT, 2009. (9) (a) Hay, P. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 270−283. (b) Wadt, W. R.; Hay, P. J. J. Chem. Phys. 1985, 82, 284−298. (c) Hay, P. J.; Wadt, W. R. J. Chem. Phys. 1985, 82, 299−310. (10) Venkatakrishnan, T. S.; Imaz, I.; Sutter, J.-P. Inorg. Chim. Acta 2008, 361, 3710−3713.

(CREST) project of the Japan Science and Technology Agency (JST), a Grant-in-Aid for Young Scientists (S) from the Japan Society for the Promotion of Science (JSPS), a Grant for the Global COE Program “Chemistry Innovation through Cooperation of Science and Engineering,” Advanced Photon Science Alliance (APSA) from the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT), and the Asahi Glass Foundation. We also recognize the Cryogenic Research Center, The University of Tokyo, and the Center for Nanolithography & Analysis, The University of Tokyo, which are supported by MEXT. K. I. is grateful for the JSPS Research Fellowships for Young Scientists.

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REFERENCES

(1) (a) Verdaguer, M.; Bleuzen, A.; Train, C.; Garde, R.; Fabrizi de Biani, F.; Desplanches, C. Philos. Trans. R. Soc., A 1999, 357, 2959− 2976. (b) Miller, J. S.; Epstein, A. J. MRS Bull. 2000, 25, 21−30. (c) Przychodzeń, P.; Korzeniak, T.; Podgajny, R.; Sieklucka, B. Coord. Chem. Rev. 2006, 250, 2234−2260. (d) Dunbar, K. R.; Heintz, R. A. Prog. Inorg. Chem. 1997, 45, 283−391. (e) Tokoro, H.; Ohkoshi, S. Dalton Trans. 2011, 40, 6825−6833. (f) Train, C.; Gruselle, M.; Verdaguer, M. Chem. Soc. Rev. 2011, 40, 3297−3312. (g) Ohkoshi, S.; Tokoro, H. Acc. Chem. Res. 2012, 45, 1749−1758. (2) (a) Varret, F.; Goujon, A.; Boukheddaden, K.; Noguès, M.; Bleuzen, A.; Verdaguer, M. Mol. Cryst. Liq. Cryst. 2002, 379, 333−340. (b) Shimamoto, N.; Ohkoshi, S.; Sato, O.; Hashimoto, K. Inorg. Chem. 2002, 41, 678−684. (c) Sato, O.; Hayami, S.; Einaga, Y.; Gu, Z.-Z. Bull. Chem. Soc. Jpn. 2003, 76, 443−470. (d) Herrera, J. M.; Marvaud, V.; Verdaguer, M.; Marrot, J.; Kalisz, M.; Mathonière, C. Angew. Chem., Int. Ed. 2004, 43, 5468−5471. (e) Arimoto, Y.; Ohkoshi, S.; Zhong, Z. J.; Seino, H.; Mizobe, Y.; Hashimoto, K. J. Am. Chem. Soc. 2003, 125, 9240−9241. (f) Ohkoshi, S.; Tokoro, H.; Matsuda, T.; Takahashi, H.; Irie, H.; Hashimoto, K. Angew. Chem., Int. Ed. 2007, 46, 3238−3241. (g) Pajerowski, D. M.; Andrus, M. J.; Gardner, J. E.; Knowles, E. S.; Meisel, M. W.; Talham, D. R. J. Am. Chem. Soc. 2010, 132, 4058− 4059. (h) Ozaki, N.; Tokoro, H.; Hamada, Y.; Namai, A.; Matsuda, T.; Kaneko, S.; Ohkoshi, S. Adv. Funct. Mater. 2012, 22, 2089−2093. (3) (a) Ohkoshi, S.; Tokoro, H.; Hashimoto, K. Coord. Chem. Rev. 2005, 249, 1830−1840. (b) Tokoro, H.; Ohkoshi, S.; Matsuda, T.; Hashimoto, K. Inorg. Chem. 2004, 43, 5231−5236. (c) Tokoro, H.; Miyashita, S.; Hashimoto, K.; Ohkoshi, S. Phys. Rev. B 2006, 73, No. 172415. (d) Vertelman, E. J. M.; Lummen, T. T. A.; Meetsma, A.; Bouwkamp, M. W.; Molnar, G.; Loosdrecht, P. H. M. V.; Koningsbruggen, P. J. V. Chem. Mater. 2008, 20, 1236−1238. (e) Tokoro, H.; Matsuda, T.; Nuida, T.; Moritomo, Y.; Ohoyama, K.; Loutete Dnagui, E. D.; Boukheddaden, K.; Ohkoshi, S. Chem. Mater. 2008, 20, 423−428. (f) Tokoro, H.; Ohkoshi, S. Appl. Phys. Lett. 2008, 93, No. 021906. (g) Tokoro, H.; Nakagawa, K.; Imoto, K.; Hakoe, F.; Ohkoshi, S. Chem. Mater. 2012, 24, 1324−1330. (4) (a) Garde, R.; Desplanches, C.; Bleuzen, A.; Veillet, P.; Verdaguer, M. Mol. Cryst. Liq. Cryst. 1999, 334, 587−595. (b) Zhong, Z. J.; Seino, H.; Mizobe, Y.; Hidai, M.; Fujishima, A.; Ohkoshi, S.; Hashimoto, K. J. Am. Chem. Soc. 2000, 122, 2952−2953. (c) Podgajny, R.; Korzeniak, T.; Balanda, M.; Wasiutynski, T.; Kemp, W. T. J.; Alcock, N. W.; Sieklucka, B. Chem. Commun. 2002, 1138− 1139. (d) Wither, J. R.; Li, D.; Triplet, J.; Ruschman, C.; Parkin, S.; Wang, G.; Yee, G. T.; Holmes, S. M. Inorg. Chem. 2006, 45, 4307− 4309. (e) Ohkoshi, S.; Tsunobuchi, Y.; Takahashi, H.; Hozumi, T.; Shiro, M.; Hashimoto, K. J. Am. Chem. Soc. 2007, 129, 3084−3085. (f) Venkatakrishnan, T. S.; Sahoo, S.; Bréfuel, N.; Duhayon, C.; Paulsen, C.; Barra, A. L.; Ramasesha, S.; Sutter, J. P. J. Am. Chem. Soc. 2010, 132, 6047−6056. (5) (a) Rombaut, G.; Verelst, M.; Golhen, S.; Ouahab, L.; Mathonière, C.; Kahn, O. Inorg. Chem. 2001, 40, 1151−1159. (b) Ohkoshi, S.; Machida, N.; Zhong, Z. J.; Hashimoto, K. Synth. Met. 2001, 122, 523−527. (c) Ohkoshi, S.; Tokoro, H.; Hozumi, T.; Zhang, Y.; Hashimoto, K.; Mathonière, C.; Bord, I.; Rombaut, G.; Verelst, M.; Moulin, C. C. D.; Villain, F. J. Am. Chem. Soc. 2006, 128, 5271


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