[Fe(nsal2trien)]SCN, a New Two-Step Iron(III) Spin Crossover Compound, with Symmetry Breaking Spin-State Transition and an Intermediate Ordered State

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• 作者：Bruno J. C. Vieira ; Joana T. Coutinho ; Isabel C. Santos ; Laura C. J. Pereira ; Jo茫o C. Waerenborgh ; Vasco da Gama
• 刊名：Inorganic Chemistry
• 出版年：2013
• 出版时间：April 1, 2013
• 年：2013
• 卷：52
• 期：7
• 页码：3845-3850
• 全文大小：293K
• 年卷期：v.52,no.7(April 1, 2013)
• ISSN：1520-510X

文摘

We report the synthesis of the iron(III) complex of the hexadentate Schiff base ligand nsal₂trien obtained from the condensation of triethylenetetramine and 2 equiv. of 2-hydroxy-1-naphthaldehyde. The study of the salt [Fe(nsal₂trien)]SCN (1) by magnetic susceptibility measurements and M枚ssbauer spectroscopy reveals a rather unique behavior that displays thermally induced spin crossover (SCO) with two well-separated steps at 250 (gradual transition) and 142 K (steep transition). Single crystal X-ray structures were obtained at 294, 150, and 50 K, for the high spin (HS), intermediate (Int), and low spin (LS) phases. The HS and LS phases are isostructural, and based on a single Fe^III site (either HS or LS) an unusual symmetry break occurs in the transition to the Int ordered phase, where the unit cell includes two distinct Fe^III sites and is based on a repetition of the [HS鈥揕S] motif. The two-step SCO behavior of 1 must result from the existence of structural constraints preventing the full conversion HS 鈫?LS in a single step.