Synthesis of Heteroleptic Cerium(III) Anionic Amido-Tethered N-Heterocyclic Carbene Complexes
作者:Stephen T. Liddle、Polly L. Arnold
DOI:10.1021/om050061b
日期:2005.5.1
t-BuNH2CH2CH2[HCMeN(CHCH)N}]2Br (12, H3L2Br2) and the amine−N-heterocyclic carbene t-BuNHCH2CH2[CMeN(CHCH)N}] (13, HL2) have been synthesized. However, attempts to prepare and isolate the lithium amido−N-heterocyclic carbene t-BuNLiCH2CH2[CMeN(CHCH)N}] (14, LiL2) were unsuccessful. Transamination of [(HL1)LiBr] (2) with [CeN(SiMe3)2}3] successfully affords the compounds [(L1)Ce(N[SiMe3]2)(μ-Br)}2] (15) and
Titanium(IV) Alkoxy-N-heterocyclic Carbenes: Structural Preferences of Alkoxide and Bromide Adducts
作者:Shaheed A. Mungur、Alexander J. Blake、Claire Wilson、Jonathan McMaster、Polly L. Arnold
DOI:10.1021/om0508839
日期:2006.4.1
synthesized and characterized. Structuralcharacterization of the n = 2 complex shows marked bending of the two ligands cis (and perpendicular) to the plane of the NHC group in the direction of the carbene, suggestive of a pseudo-back-bonding interaction between adjacent ligands and the carbene p orbital, consistent with a bonding model recently proposed for d0 metal-NHC complexes. However, inspection of
Ti(L)(O i Pr)n(Br)3 - n(n = 1-3,L = t BuNHCH )形式的酰胺键合的N杂环卡宾(NHC)的一系列钛(IV)加合物已经合成并表征了2 CH 2 [C N t Bu(CHCH)N}]。n = 2配合物的结构表征表明,两个配体在卡宾方向上均与NHC基团平面成顺式(垂直)弯曲,这表明相邻配体与卡宾p之间存在假反向键相互作用轨道,与最近针对d 0提出的键合模型一致金属-NHC配合物。但是,对空间填充模型的检查和使用DFT方法计算键序的结果表明,弯曲是由于配合物中相邻的π供体配体上的孤对之间的排斥所致,而不是NHC与顺式π之间的任何特定相互作用-供体配体。
Bent metal carbene geometries in amido N-heterocyclic carbene complexes
作者:Shaheed A. Mungur、Stephen T. Liddle、Claire Wilson、Mark J. Sarsfield、Polly L. Arnold
DOI:10.1039/b410074c
日期:——
Lithium(I) and uranium(VI) amido-tethered But-substituted N-heterocyclic carbene (NHC) complexes exhibit very distorted metal–carbene bonds; the corresponding magnesium(II) and mesityl-substituted NHC uranium(VI) complexes are undistorted; the distortion does not affect the ligand binding strength, suggesting a dominance of electrostatic character in closed-shell electropositive metal–carbene bonds.
The Zirconium Benzyl Mediated C−N Bond Cleavage of an Amino-Linked N-Heterocyclic Carbene
作者:Yu-Cheng Hu、Chung-Chih Tsai、Wei-Chih Shih、Glenn P. A. Yap、Tiow-Gan Ong
DOI:10.1021/om900971c
日期:2010.2.8
We report a nonreductive process mediated by zirconium alkylcomplexes for the C−Hbondactivation and C−N bond cleavage of an anionic amino-linked carbene at room temperature. Reacting the amino-linked NHC with Zr(Bz)4 led to the isolation of a rare species of metastable Zr complex possessing an azaallyl and an η2-N,C-imidazolyl carbene moiety.