1,2-Diethynylbenzene-Bridged [Cp*(dppe)Fe]n+ Units: Effect of Steric Hindrance on the Chemical and Physical Properties

详细信息    查看全文

• 作者：Rim Makhoul ; Hiba Sahnoune ; Vincent Dorcet ; Jean-Fran莽ois Halet ; Jean-Ren茅 Hamon ; Claude Lapinte
• 刊名：Organometallics
• 出版年：2015
• 出版时间：July 13, 2015
• 年：2015
• 卷：34
• 期：13
• 页码：3314-3326
• 全文大小：627K
• ISSN：1520-6041

文摘

The binuclear complex [{Cp*(dppe)Fe鈥揅鈮鈭拀₂-渭-(1,2-C₆H₄)] (o-1) was prepared via the bis(vinylidene) [{(Cp*(dppe)Fe鈺怌鈺怌H鈭拀₂-渭-(1,2-C₆H₄)](PF₆)₂ (o-1H₂(PF₆)₂) in good yield. The new complex was characterized by ESI-mass spectrometry, IR, multinuclear NMR, and M枚ssbauer spectroscopies, X-ray diffraction on a single crystal, and cyclic voltammetry. The data are consistent with a strong steric interaction between the vicinal organoiron centers responsible for the very long time of reaction for the preparation of o-1. The singly and doubly oxidized forms o-1(PF₆) and o-1(PF₆)₂ were prepared by oxidation of o-1 with 1 and 2 equiv of ferrocenium salt. These salts were characterized by high-resolution ESI-mass spectra, XRD analyses on single crystals, and IR, M枚ssbauer, ESR, UV鈥搗is, and NIR spectroscopies. In addition, the magnetic properties of compound o-1(PF₆)₂ were investigated by ¹H and ³¹P NMR. The data were analyzed with the support of quantum chemistry calculations at the DFT level of theory. The radical cation o-1(PF₆) belongs to class IIB of the mixed-valence classification (H_ab < 1500 cm^鈥?). The narrowness of the IVCT bands is explained by the steric hindrance, which limits the number of conformers. The singlet/triplet states ratio is independent of the temperature for the doubly oxidized complex o-1(PF₆)₂.