General Preparation of (N3N)ZrX (N3N = N(CH2CH2NSiMe3)33−) Complexes from a Hydride Surrogate

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• 作者：Andrew J. Roering ; Annalese F. Maddox ; L. Taylor Elrod ; Stephanie M. Chan ; Michael B. Ghebreab ; Kyle L. Donovan ; Jillian J. Davidson ; Russell P. Hughes ; Tamila Shalumova ; Samantha N. MacMillan ; Joseph
• 刊名：Organometallics
• 出版年：2009
• 出版时间：January 26, 2009
• 年：2009
• 卷：28
• 期：2
• 页码：573-581
• 全文大小：250K
• 年卷期：v.28,no.2(January 26, 2009)
• ISSN：1520-6041

文摘

A homoleptic triamidoamine zirconium complex featuring a metalated trimethylsilyl substituent, [κ⁵-(Me₃SiNCH₂CH₂)₂NCH₂CH₂NSiMe₂CH₂]Zr (1), was synthesized by reaction of Zr(CH₂Ph)₄ with N(CH₂CH₂NHSiMe₃)₃ followed by sublimation. Complex 1 is a general precursor to a family of complexes with the formulation (N₃N)ZrX (N₃N = N(CH₂CH₂NSiMe₃)₃³⁻, X = anionic ligand) by reactions that parallel expected reactivity of a hydride derivative. Treatment of 1 with phosphines, amines, thiols, alkynes, and phenol resulted in the formation of new, pseudo-C_3v-symmetric (N₃N)ZrX complexes (X = phosphido, amido, alkynyl, thiolate, or phenoxide) via element−H bond activation. Thus, the reactivity of complex 1 is that best described as a hydride surrogate. For example, complex 1 reacted with PhPH₂ at ambient temperature to provide (N₃N)ZrPHPh (2) in 86% yield. Density functional theory studies and X-ray crystal structures provide a general overview of the bonding in these complexes, which appears to be highly ionic. In general, there is little evidence for ligand-to-metal π-bonding for the pseudoaxial X ligand in these complexes except for strongly π-basic terminal amido ligands. The limited π-bonding appears to be the result of competitive π-donation by the pseudoequatorial amido arms of the triamidoamine ancillary ligand. Thus, the relative Zr−X bond energies are governed by the basicity of the anionic ligand X. Solid-state structures of phosphido (3, 4, 5), amido (10), and thiolate (15) complexes support the computational results.