頁籤選單縮合
題名 | Metal String Complexes: Synthesis, Crystal Structures and Magnetic Properties of Heptanuclear Nickel (Ⅱ) Complexes, [Ni乣(μ乣-teptra)[feb2]×[feaf]](teptra=tetrapyridyltriamido,X=CI,NCS)= |
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作者 | 賴旭洋; 王志傑; 陳裕華; 李忠洲; 劉怡宏; 彭旭明; Lai, Shie-yang; Wang, Chih-chieh; Chen, Yu-hua; Lee, Chung-chou; Liu, Yi-hung; Peng, Shie-ming; |
期刊 | Journal of the Chinese Chemical Society |
出版日期 | 19990600 |
卷期 | 46:3 1999.06[民88.06] |
頁次 | 頁477-485 |
分類號 | 340 |
語文 | eng |
關鍵詞 | Ni-Ni string complexes; Metal-metal bond; Molecular metalwires; Oligo-α-pyridylamido complexes; |
英文摘要 | The synthesis, crystal structures and magnetic properties of linear heptanuclear nickel(II) complexes [Ni□(μ□-teptra)□X□], (teptra = tetrapyridyltriamido), with the axial ligand X = C1□ (1), NCS□ (2), are reported. The hepta-nuclear metal chain is helically wrapped by four syn-syn-syn-syn-syn-syn teptra□ ligands. Both of the [Ni□(μ□-teptra)□]□ moiety are isostructural involving a Ni□ linear chain unit with all of the ∠Ni-Ni-Ni being 180°, terminated by two axial ligands. Three types of Ni-Ni distances are found in these complexes. The longest ones bonded with the axial ligands are 2.383(1), 2.374(2) and 2.375(2), 2.354(2), and the intermediate ones are 2.310(1), 2.304(1) and 2.300(2), 2.303(2) A for (1) and (2), respectively. The innermost Ni-Ni distances are the shortest ones with the distances of 2.226(2), 2.214(2) and 2.194(2), 2.206(2) A for (1) and (2), respectively. Two terminal Ni(II) ions bonded with the axial ligands are in a square-pyramidal (NiN□X) environment and exhibit long Ni-N bonds (-2.10 A) which are consistent with a high-spin Ni(II) configuration. The inner five Ni(II) ions displayed short Ni-N (-1.90 A) bond distances which are consistent with a square-planar (NiN□), diamagnetic arrangement of a low-spin Ni(II) configuration. The magnetic measurement of (1) shows an antiferromagnetic interaction of two terminal high-spin Ni(II) ions with the coupling constant J = -3.8 cm□. The Ni- Ni, Ni-N distances and magnetic behavior among tri-, penta-, and hepta-nickel(II) complexes are compared and discussed. |
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