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(D
IPP),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