Flexible Binding of PNP Pincer Ligands to Monomeric Iron Complexes

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• 作者：Kathlyn L. Fillman ; Elizabeth A. Bielinski ; Timothy J. Schmeier ; Jared C. Nesvet ; Tessa M. Woodruff ; Cassie J. Pan ; Michael K. Takase ; Nilay Hazari ; Michael L. Neidig
• 刊名：Inorganic Chemistry
• 出版年：2014
• 出版时间：June 16, 2014
• 年：2014
• 卷：53
• 期：12
• 页码：6066-6072
• 全文大小：313K
• 年卷期：v.53,no.12(June 16, 2014)
• ISSN：1520-510X

文摘

Transition metal complexes supported by pincer ligands have many important applications. Here, the syntheses of five-coordinate PNP pincer-supported Fe complexes of the type (PNP)FeCl₂ (PNP = HN{CH₂CH₂(PR₂)}₂, R = iPr (^iPrPNP), tBu (^tBuPNP), or cyclohexyl (^CyPNP)) are reported. In the solid state, (^iPrPNP)FeCl₂ was characterized in two different geometries by X-ray crystallography. In one form, the ^iPrPNP ligand binds to the Fe center in the typical meridional geometry for a pincer ligand, whereas in the other form, the ^iPrPNP ligand binds in a facial geometry. The electronic structures and geometries of all of the (PNP)FeCl₂ complexes were further explored using ⁵⁷Fe M枚ssbauer and magnetic circular dichroism spectroscopy. These measurements show that in some cases two isomers of the (PNP)FeCl₂ complexes are present in solution and conclusively demonstrate that binding of the PNP ligand is flexible, which may have implications for the reactivity of this important class of compounds.