Bis[(trimethylsilyl)methyl]manganese: Structural Variations of Its Solvent-Free and TMEDA-, Pyridine-, and Dioxane-Complexed Forms

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• 作者：Antonio Alberola^† ; ; Victoria L. Blair^‡ ; ; Luca M. Carrella^§ ; ; William Clegg ; Alan R. Kennedy^‡ ; ; Jan Klett^‡ ; ; Ro
• 刊名：Organometallics
• 出版年：2009
• 出版时间：April 13, 2009
• 年：2009
• 卷：28
• 期：7
• 页码：2112-2118
• 全文大小：220K
• 年卷期：v.28,no.7(April 13, 2009)
• ISSN：1520-6041

文摘

First synthesized in 1976 and recently taking on a new significance as a key precursor to heterobimetallic alkali-metal−manganese(II) complexes, bis[(trimethylsilyl)methyl]manganese has been structurally characterized by X-ray crystallography. It forms a polymeric chain structure of formula [{Mn(CH₂SiMe₃)₂}_∞], 1, in which distorted tetrahedral, spiro Mn atoms are linked together via μ₂-bonding alkyl ligands. The structure is notable for displaying two distinct categories of Mn−C bond lengths with a mean size differential of 0.225 Å and for being the first fully crystallographically characterized polymeric manganese(II) dialkyl compound. Magnetic measurements of 1 indicate a surprisingly strong spin exchange coupling of J ≈ −45 cm⁻¹ between the manganese ions aligned along the chain. Four Lewis base complexes of bis[(trimethylsilyl)methyl]manganese have also been subjected to X-ray crystallographic studies. Previously known [TMEDA·Mn(CH₂SiMe₃)₂], 2, and [(pyridine)₂Mn(CH₂SiMe₃)₂], 3, both adopt a simple monomeric arrangement with C₂N₂ distorted tetrahedral coordinations of the metal atom. Synthesized by direct addition of the Lewis base to 1, two further, new complexes, [{(dioxane)[Mn(CH₂SiMe₃)₂]₂}_∞], 4, and [{(dioxane)[Mn(CH₂SiMe₃)₂]}_∞], 5, are also reported. Hemisolvate 4 displays dimeric [(Me₃SiCH₂)Mn(μ-CH₂SiMe₃)₂Mn(CH₂SiMe₃)] subunits, whereas 1:1 solvate 5 consists of monomeric subunits of [{Mn(CH₂SiMe₃)₂}_∞]; in both cases these subunits are linked together via O(CH₂CH₂)₂O bridges to generate one-dimensional polymers.