Deprotonation in Mixed-Valent Diiron(II,III) Complexes with Aniline or Benzimidazole Ligands

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• 作者：Eric Gour茅 ; Micha毛l Carboni ; Ang茅lique Troussier ; Patrick Dubourdeaux ; Martin Cl茅mancey ; Nathalie Gon ; Ramachandran Balasubramanian ; Colette Lebrun ; Jacques P茅caut ; Genevi猫ve Blondin ; Jean-Marc Latour
• 刊名：Inorganic Chemistry
• 出版年：2015
• 出版时间：July 6, 2015
• 年：2015
• 卷：54
• 期：13
• 页码：6257-6266
• 全文大小：669K
• ISSN：1520-510X

文摘

We have previously investigated cis/trans isomerization processes in phenoxido-bridged mixed-valent Fe^IIFe^III complexes that contain either one aniline or one anilide ligand. In this work, we compare the properties of similar complexes bearing one terminal protic ligand, either aniline or 1H-benzimidazole. Whatever the ligand, ¹H NMR spectroscopy clearly evidences that the complexes are present in CH₃CN as a mixture of cis- and trans-isomers in a close to 1:1 ratio. We show here that addition of NEt₃ indeed allows the deprotonation of these ligands, the resulting complexes bearing either anilide or benzimidazolide that are coordinated to the ferric site. The latter are singular examples of a high-spin ferric ion coordinated to a benzimidazolide ligand. Whereas the trans-isomer of the anilide complex is the overwhelming species, benzimidazolide species are mixtures of cis- and trans-isomers in equal proportions. Moreover, cyclic voltammametry studies show that Fe^IIIFe^III complexes with 1H-benzimidazole are more stable than their aniline counterparts, whereas the reverse is observed for the deprotonated species.