Two-Step Spin-Transition Iron(III) Compound with a Wide [High Spin-Low Spin] Plateau

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• 作者：Jinkui Tang^† ; ^‡ ; ; Jos Snchez Costa^† ; ; Simon Smulders^† ; ; Gbor Molnr^§ ; ; Azzedine Bousseksou^§ ; ; Simon J. Teat<
• 刊名：Inorganic Chemistry
• 出版年：2009
• 出版时间：March 2, 2009
• 年：2009
• 卷：48
• 期：5
• 页码：2128-2135
• 全文大小：316K
• 年卷期：v.48,no.5(March 2, 2009)
• ISSN：1520-510X

文摘

A new iron(III) coordination compound exhibiting a two-step spin-transition behavior with a remarkably wide [HS-LS] plateau of about 45 K has been synthesized from a hydrazino Schiff-base ligand with an N,N,O donor set, namely 2-methoxy-6-(pyridine-2-ylhydrazonomethyl)phenol (Hmph). The single-crystal X-ray structure of the coordination compound {[Fe(mph)₂](ClO₄)(MeOH)_0.5(H₂O)_0.5}₂ (1) determined at 150 K reveals the presence of two slightly different iron(III) centers in pseudo-octahedral environments generated by two deprotonated tridentate mph ligands. The presence of hydrogen bonding interactions, instigated by the well-designed ligand, may justify the occurrence of the abrupt transitions. 1 has been characterized by temperature-dependent magnetic susceptibility measurements, EPR spectroscopy, differential scanning calorimetry, and ⁵⁷Fe Mssbauer spectroscopy, which all confirm the occurrence of a two-step transition. In addition, the iron(III) species in the high-spin state has been trapped and characterized by rapid cooling EPR studies.