N-Heterocyclic Carbene Complexes of Three- and Four-Coordinate Fe(I)

详细信息    查看全文

• 作者：Yasuhiro Ohki ; Ryoko Hoshino ; Kazuyuki Tatsumi
• 刊名：Organometallics
• 出版年：2016
• 出版时间：May 23, 2016
• 年：2016
• 卷：35
• 期：10
• 页码：1368-1375
• 全文大小：480K
• 年卷期：0
• ISSN：1520-6041

文摘

N-heterocyclic carbene complexes of three- and four-coordinate Fe(I), [Fe(L^R)₄][PF₆] (L^R = 1,3-R₂-4,5-dimethylimidazol-2-ylidene, R = Me (2), Et (3), ⁱPr (4)) and [Fe(L^Mes)₂(THF)][PF₆] (5) (L^Mes = 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene), were synthesized from successive reactions of [Fe(toluene)₂][PF₆]₂ with 1 equiv of KC₈ and L^R (4 equiv for R = Me, Et, ⁱPr; 2 equiv for R = Mes). The coordination geometry of the iron atom in these complexes varies depending on the nature of the R group in L^R: a tetrahedral geometry was observed for 2, a square-planar one for 3 and 4, and a three-coordinate T-shaped one for 5. In solution, 4 releases L^iPr ligand(s), while the L^R ligands of the other Fe(I) complexes remain firmly bound. Tetrahedral 2 and T-shaped 5 contain a high-spin (S = ³/₂) Fe(I) center, whereas square-planar 3 and 4 contain Fe(I) in the low-spin state (S = ¹/₂).