Synthesis and Structure of Cubane-Type Tetrairon Clusters Possessing 渭3-Isonitrile Ligands. Reductive Coupling of Two Isonitriles on Redox-Responsive Tetrairon Reaction Sites
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- 作者：Masaaki Okazaki ; Kosei Suto ; Naotsugu Kudo ; Masato Takano ; Fumiyuki Ozawa
- 刊名：Organometallics
- 出版年：2012
- 出版时间：June 11, 2012
- 年：2012
- 卷：31
- 期：11
- 页码：4110-4113
- 全文大小：328K
- 年卷期：v.31,no.11(June 11, 2012)
- ISSN：1520-6041
文摘
A 3:1 molar ratio mixture of [(畏5-C5H4Me)4Fe4(HCCBr)2](PF6) (1a) and [(畏5-C5H4Me)4Fe4(HCCH)(BrCCBr)](PF6) (1b) was converted to [(畏5-C5H4Me)4Fe4(渭3-CH)2(渭3-CNPh)2](PF6)2 (2) upon treatment with aniline, followed by NiPr2Et and finally [Cp2Fe](PF6). The X-ray diffraction analysis revealed that 2 can be described as a cubane-type tetrairon cluster possessing two 渭3-CH and two 渭3-isonitrile ligands. Treatment of 2 with 2.5 equiv of [Cp2Co] gave the neutral form 3, formulated as [(畏5-C5H4Me)4Fe4(HCCH)2(渭3-CNPh)2]. The redox reactions were chemically reversible; treatment of 3 with [Cp2Fe](PF6) reproduced 2 quantitatively. The structure of 3 was determined by X-ray diffraction analysis. The molecule exhibits a butterfly geometry resulting from the scission of one of the iron鈥搃ron bonds of the tetrahedron in 2. In accordance with the conversion of the core structure from tetrahedron to butterfly, the coupling of two 渭3-CH ligands occurs to form an acetylene ligand. Further treatment of 3 with LiAlH4 followed by air-oxidation resulted in reductive coupling of two isonitrile ligands to give a bis(acetylene) cluster, [(畏5-C5H4Me)4Fe4(HCCH)2](PF6) (6).