Mono- versus Bis-chelate Formation in Triazenide and Amidinate Complexes of Magnesium and Zinc

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• 作者：Nonsee Nimitsiriwat ; Vernon C. Gibson ; Edward L. Marshall ; Pittaya Takolpuckdee ; Atanas K. Tomov ; Andrew J. P. White ; David J. Williams ; Mark R. J. Elsegood ; Sophie H. Dale
• 刊名：Inorganic Chemistry
• 出版年：2007
• 出版时间：November 12, 2007
• 年：2007
• 卷：46
• 期：23
• 页码：9988 - 9997
• 全文大小：243K
• 年卷期：v.46,no.23(November 12, 2007)
• ISSN：1520-510X

文摘

Magnesium and zinc complexes of the monoanionic ligands N,N'-bis(2,6-di-isopropylphenyl)triazenide, L¹, N,N'-bis(2,6-di-isopropylphenyl)acetamidinate, L², and N,N'-bis(2,6-di-isopropylphenyl)tert-butylamidinate, L³, have beensynthesized, but only L³ possesses sufficient steric bulk to prevent bis-chelation. Hence, the reaction of L¹H withexcess ZnEt₂ leads to the isolation of (L¹)₂Zn, 1; L¹H also reacts with Bu₂Mg in Et₂O to afford (L¹)₂Mg(Et₂O), 2.Similar reactivity is observed for L²H, leading to the formation of (L²)₂Zn, 3, and (L²)₂Mg, 4. The reaction of L²Hwith ZnR₂ may also afford the tetranuclear aggregates {(L²)Zn₂R₂}₂O, 5 (R = Me) and 6 (R = Et). By contrast,the tert-butylamidinate ligand was found to exclusively promote mono-chelation, allowing (L³)ZnCl(THF), 7, [(L³)Zn(-Cl)]₂, 8, (L³)ZnN(SiMe₃)₂, 9, (L³)MgⁱPr(Et₂O), 10, and (L³)MgⁱPr(THF), 11, to be isolated. X-ray crystallographicanalyses of 1, 2, 3, 4, 5, 6, 8, and 10 indicate that the capacity of L³ to resist bis-chelation is due to greateroccupation of the metal coordination sphere by the N-aryl substituents.