A series of NHC pre-ligands featuring a pendant phosphonium moiety attached to N′ position through a propyl linker was readily obtained upon quaternization of N-mesityl- and N-methyl-imidazole, or N-mesityl-imidazoline using (3-bromo-propyl)-triphenylphosphonium bromide. Reactions of the resulting dicationic salts with [PdCl(allyl)]₂ in the presence of K₂CO₃ afforded the anticipated NHC-ligated Pd(II) metal complexes in high yields. Further treatment of the latter complexes with tBuOK induced a deprotonation of the carbon atom adjacent to the phosphonium moiety and the formation of the corresponding C,C-chelating NHC-phosphonium ylide Pd(II) complexes. Investigation of an alternative synthetic route involving a silver transmetallation reaction incidentally allowed isolation and full characterization of an unusual dimeric tetranuclear NHC Ag(I) complex of general formula [(NHC∼P⁺)₂(Ag₄Br₆)²⁻].

中文翻译：

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方便获得N-膦酰基取代的NHC金属络合物[M = Ag（I），Rh（I），Pd（II）]

一系列NHC的预配体设有通过丙基接头连接到N'位置的侧鏻部分时的季铵化容易地获得Ñ -mesityl-和Ñ甲基-咪唑，或ñ使用-基-咪唑啉（3-溴丙基）-三苯基溴化.。在K ₂ CO ₃的存在下，所生成的两性盐与[PdCl（烯丙基）] _2的反应以高收率提供了预期的NHC连接的Pd（II）金属配合物。用t BuOK进一步处理后者的配合物，会导致与moiety部分相邻的碳原子去质子化并形成相应的C，C螯合NHC-叶立德Pd（II）配合物。对涉及银的金属转移反应的另一种合成途径的研究偶然地分离出了通式[（NHC〜P ⁺）₂（Ag ₄ Br ₆）^2-的不寻常的二聚四核NHC Ag（I）配合物并对其进行了全面表征。