Ionic liquid mediated synthesis and x-ray crystal structure of trans-difluorotetrakis- (1-methylimidazole)iron(III) tetrafluoroborate
Ionic liquid mediated synthesis and x-ray crystal structure of trans-difluorotetrakis- (1-methylimidazole)iron(III) tetrafluoroborate
复制标题
离子液体介导的反式二氟四-(1-甲基咪唑)铁(III)四氟硼酸盐的合成及X射线晶体结构
DOI：
10.1021/ic00075a078
复制
发表时间：
1993
期刊：
影响因子：
--
通讯作者：
M. Zaworotko
中科院分区：
文献类型：
--
作者：
S. Christie;S. Subramanian;Lihong Wang;M. Zaworotko
铁 (III) 对简单单齿氮配体的亲和力较低，并且此类配合物不存在于水溶液中。 1 事实上，尽管 1-甲基咪唑 (1-Meim) 2 和 2-甲基咪唑基 (2-Meinr) 3 配体的八面体铁 (II) 配合物是已知的，并且已通过 X 射线晶体学进行了表征，但它们相应的铁 (III) 类似物尚不清楚。然而，已经制备了大量轴向含有咪唑的卟啉4·5 和salen 型配体6 的五配位和六配位铁(III) 配合物，并通过单晶X 射线晶体学对其进行了表征。对这些复合物的结构表征所表现出的兴趣可归因于铁在天然存在的血红素和非血红素金属酶中相似的配位环境中的普遍存在。 7 在此类复合物中，显然轴向配体在控制铁中心的自旋状态以及底物分子的结合方面发挥着重要作用。 8 除了上述铁卟啉络合物外，许多简单的铁络合物 9 和具有源自咪唑的多齿配体的多核氧代铁簇 10 也已得到表征，主要作为非血红素酶中铁中心的模型。然而，据我们所知，1-Meim 的简单伪八面体铁 (III) 配合物尚未通过 X 射线晶体学进行表征。
Iron (III) has a low affinity for simplemonodentate nitrogen ligands, and such complexes do not exist in aqueous solution. 1 Indeed, although octahedral iron (II) complexes of 1-methylim-idazole (1-Meim) 2 and 2-methylimidazolato (2-Meinr) 3 ligands are known and have been characterized by X-ray crystallography, their corresponding iron (III) analogues are unknown. However, a large number of five-and six-coordinate iron (III) complexes of porphyrins4· 5 and salen type ligands6 containing imidazole in axial positions have been prepared and characterized by singlecrystal X-ray crystallography. The interest shown in the structural characterization of these complexes can be attributed to the prevalence of iron in similar coordination environments in naturally occurring heme and non-heme metalloenzymes. 7 In such complexes it is apparent that the axial ligands play an important role in controlling the spin state of the iron center and hence the binding of substrate molecules. 8 Besides the aforementioned iron porphyrin complexes, a number of simple iron complexes9 andpolynuclear oxoiron clusters10 with multidentate ligands derived from imidazoles have been characterized, primarily as models of iron centers in non-heme enzymes. However, to our knowledge a simple pseudo-octahedral iron (III) complex of 1-Meim has not been characterized by X-ray crystallography.