A new synthetic pathway for the N-heterocyclic carbene adduct (NHCMe)SiCl4 (2) (NHCMe = 1,3-dimethylimidazolidin-2-ylidene) using silicochloroform is presented. Supported by DFT calculations, the energy for dissociation of 2 into the carbene and the SiCl4 fragment was found to be comparable to carbene transfer reagents based on silver(I) chloride. Compound 2 was used to transfer the NHC ligand to three different phosphorus(III) chloro compounds, resulting in the neutral complexes (NHCMe)PCl3 (3a), (NHCMe)PCl2Ph (3b) and (NHCMe)PCl2Me (3c). The sterically non-demanding NHC ligand allowed the phosphorus(III) in complex 3a to be oxidized to phosphorus(V) without loss of the NHC ligand, and afford (NHCMe)PF4H (4). Furthermore, bis-carbene complexes of Ni(II) (5) and Pd(II) (6) were obtained by reacting 2 with the respective metal chlorides.
提出了一种使用
硅氯仿合成N-杂环卡宾加合物(NHCMe)SiCl4 (2)的新合成途径(NHCMe = 1,3-二甲基
咪唑啉-2-亚氮基)。通过密度泛函理论(DFT)计算,发现化合物2解离为卡宾和SiCl4片段的能量与基于
氯化银(I)的卡宾转移试剂相当。化合物2被用于将NHC
配体转移到三种不同的
磷(III)
氯化合物上,生成了中性配合物(NHCMe)PCl3 (3a)、(NHCMe)PCl2Ph (3b)和(NHCMe)PCl2Me (3c)。空间需求较小的NHC
配体使得复合物3a中的
磷(III)能够在不失去NHC
配体的情况下被氧化为
磷(V),生成(NHCMe)PF4H (4)。此外,通过将化合物2与相应的
金属
氯化物反应,获得了Ni(II)(5)和Pd(II)(6)的双卡宾配合物。