Two Mononuclear Iron(II) Spin-Crossover Complexes with a N4O2 Coordination Sphere

Authors

  • Li Zhang,

    1. Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China, Fax: +86-10-62751708, http://www.pku.edu.cn
    2. Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, P. R. China
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  • Guan-Cheng Xu,

    1. Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China, Fax: +86-10-62751708, http://www.pku.edu.cn
    2. Institute of Applied Chemistry, Xinjiang University, Urumqi 830046, P. R. China
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  • Zhe-Ming Wang,

    1. Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China, Fax: +86-10-62751708, http://www.pku.edu.cn
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  • Song Gao

    1. Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China, Fax: +86-10-62751708, http://www.pku.edu.cn
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Abstract

Two mononuclear spin-crossover compounds Fe(L1)2 (1) and Fe(L2)2 (2) {HL1 = 2-hydroxy-3-methyl-N′-[1-(pyridine-2-yl)butylidene]benzohydrazide, HL2 = 2-hydroxy-N′-[1-(pyridine-2-yl)butylidene]benzohydrazide} were successfully synthesized. The magnetic measurements of the compounds revealed different thermal magnetic behavior. Compound 1 undergoes a gradual complete thermal spin crossover (SCO) with T1/2↑/↓ = 243/240 K and a hysteresis loop of 3 K. Compound 2 shows a gradual incomplete SCO during the measurable temperature region with T1/2 ≈ 330 K. Through the comparison of the magnetic and structural results for 1 and 2 with previously reported related compounds, the alkyl substitutions of the ligand were considered to affect the ligand-field strength and hydrogen-bonding interactions. In addition, photomagnetism results showed an 87 % photoconversion and 36 K of T(LIESST) (LIESST = light-induced excited spin-state trapping) for compound 1. The results enrich the knowledge on how to control the spin-crossover behavior in the new system.

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