Synthesis, Structures, and Reactivity of Chelating Bis-N-Heterocyclic-Carbene Complexes of Iron(II)
作者:Sergey Zlatogorsky、Christopher A. Muryn、Floriana Tuna、David J. Evans、Michael J. Ingleson
DOI:10.1021/om200605b
日期:2011.9.26
separated from two co-products, one of which was characterized by X-ray crystallography and zero-field 57Fe Mössbauer spectroscopy as the square-planar complex [((iPrC)2Ph)2Fe][I]2. The disparate reactivity toward Fe(N(SiMe3)2)2(THF) is due to the increase in linker length and decrease in linker flexibility of the phenylene-linked bis-carbene ligand relative to the methylene analogue. The short, flexible
扭曲的四面体(双卡宾)FeX 2络合物可以通过将含CH 2或亚苯基连接基的螯合双咪唑鎓盐与Fe(N(SiMe 3)2)2(THF)直接金属化来合成。对于亚甲基双(N -R-咪唑-2-亚基)((R C)2 CH 2),高自旋络合物((R C)2 CH 2)FeX 2(R = i Pr或2,6-di -异丙基苯基(DIPP),X = I或Br)可以很好地分离出来。相反,亚苯基连接的同类物((iPr C)2Ph)FeI 2无法与两种副产物分离,其中一种通过X射线晶体学和零场57 FeMössbauer光谱学表征为方平面络合物[((iPr C)2 Ph)2 Fe] [ I] 2。对Fe(N(SiMe 3)2)2(THF)的不同反应性是由于亚苯基连接的双卡宾配体相对于亚甲基类似物的连接基长度增加和连接基柔性降低。短而灵活的-CH 2-接头将唑环伸入xy平面(定义为卡宾-铁键方向)且远离假轴阴离子取代基,而刚性的亚苯基接头((R