Homoleptic versus Heteroleptic Formation of Mononuclear Fe(II) Complexes with Tris-Imine Ligands

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• 作者：Leoní A. Barrios ; Carlos Bartual-Murgui ; Eugènia Peyrecave-Lleixà ; Boris Le Guennic ; Simon J. Teat ; Olivier Roubeau ; Guillem Aromí
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：May 2, 2016
• 年：2016
• 卷：55
• 期：9
• 页码：4110-4116
• 全文大小：376K
• 年卷期：0
• ISSN：1520-510X

文摘

We show a marked tendency of Fe(II) to form heteroleptic [Fe(L)(L′)](ClO₄)₂ complexes from pairs of chelating tris-imine 3bpp, tpy, or 2bbp ligands. New synthetic avenues for spin crossover research become thus available, here illustrated with three new heteroleptic compounds with differing magnetic behaviors: [Fe(H₄L1)(Cl-tpy)](ClO₄)₂·C₃H₆O (1), [Fe(H₂L3)(Me3bpp)](ClO₄)₂·C₃H₆O (2), [Fe(H₄L1)(2bbp)](ClO₄)₂·3C₃H₆O (3). Structural studies demonstrate that 1 is in the low-spin (LS) state up to 350 K, while complexes 2 and 3 are, by contrast, in the high-spin (HS) state down to 2 K, as corroborated through magnetic susceptibility measurements. Upon exposure to the atmosphere, the latter exhibits the release of three molecules of acetone per complex, turning into the solvent-free analogue [Fe(H₄L1)(2bbp)](ClO₄)₂ (3a), through a single-crystal-to-single-crystal transformation. This guest extrusion process is accompanied by a spin switch, from HS to LS.