PdMe(C,N,C'-2,6-bis[(3-tert-butylimidazolin-2-yliden-1-yl)-methyl]pyridine) | 886968-34-9

• 英文名称: PdMe(C,N,C'-2,6-bis[(3-tert-butylimidazolin-2-yliden-1-yl)-methyl]pyridine)
• 英文别名: methyl(C,N,C'-2,6-bis(3-tert-butylimidazolin-2-yliden-1-methyl)pyridine)palladium(II) tetrafluoroborate
• CAS: 886968-34-9
• 化学式: BF₄*C₂₂H₃₂N₅Pd
• 分子量: 559.754
• InChiKey: OHKWJGLNKYDDOM-UHFFFAOYSA-N

反应信息

• 作为产物：
  描述：

  2,6-bis[(3-tert-butylimidazolium-1-yl)methyl]pyridine dibromide 、 silver tetrafluoroborate 、 chloromethyl(1,5-cyclooctadiene)palladium(II) 、 silver(l) oxide 以 二甲基亚砜 为溶剂， 以68%的产率得到PdMe(C,N,C'-2,6-bis[(3-tert-butylimidazolin-2-yliden-1-yl)-methyl]pyridine)
  参考文献：
  名称：

  Methyl-palladium(II) complexes of pyridine-bridged bis(nucleophilic heterocyclic carbene) ligands: Substituent effects on structure, stability, and catalytic performance

  摘要：

  A series of discrete, mononuclear palladium(II)-methyl complexes, together with several palladium(II)-chloro analogues, of pyridine-functionalised bis-NHC ligands have been prepared via ligand transmetallation from the silver(l)-NHC complexes. The reported complexes comprise examples with both the methylene-bridged 2,6-bis[(3-R-imidazolin-2-yliden-1-yl)methyl]pyridine (C-R<^>N<^>C; R = Mes, dipp, 'Bu) and planar 2,6-bis(3-R-imidazolin-2-yliden-1-yl)pyridine (RCNC; R = Mes, dipp) ligands and, when combined with the previously reported C-Me<^>N<^>C/MeCNC examples, cover a broad spectrum of ligand substituent steric and electronic properties, including the bulky Mes and dipp groups frequently used in catalytic applications. The palladium(II) complexes have been characterised by a variety of methods, including single crystal X-ray crystallography, with the shielding of the Pd-Me groups in the proton NMR spectra of some of the N-aryl substituted examples correlated with the proximity of the aryl rings to the methyl group in the solid state structures. The [PdMe(C-R<^>N<^>C/RCNC)](+) complexes undergo thermal degradation via reductive methyl-NHC coupling to give 2-methyl-3-R-imidazolium-1-yl species with relative stabilities in the order of [PdMe(C-Mes<^>N<^>C)]BF4 > [PdMe(C-Me<^>N<^>C)]BF4 approximate to [PdMe(MesCNC)]BF4 > [PdMe(MeCNC)]BF4 > [PdMe(C-tBu<^>N<^>C)]BF4 >> [PdMe(tBuCNC)]BF4 (not isolable). A comparison of the activity of the complexes as precatalysts in a model Heck coupling reaction shows greatest activity in those species bearing bulkier N-substituents, with complexes bearing C-R<^>N<^>C ligands generally more efficient precatalysts than those bearing RCNC ligands. (c) 2005 Elsevier B.V. All rights reserved.

  DOI：

  10.1016/j.ica.2005.07.049