Iron Complexes of Dendrimer-Appended Carboxylates for Activating Dioxygen and Oxidizing Hydrocarbons
作者:Min Zhao、Brett Helms、Elena Slonkina、Simone Friedle、Dongwhan Lee、Jennifer DuBois、Britt Hedman、Keith O. Hodgson、Jean M. J. Fréchet、Stephen J. Lippard
DOI:10.1021/ja076817a
日期:2008.4.1
[Fe2([G-3]COO)4(4-RPy)2] were prepared, where [G-3]COO- is a third-generation dendrimer-appended terphenyl carboxylate ligand and 4-RPy is a pyridine derivative. The dendrimer environment provides excellent protection for the diiron center, reducing its reactivity toward dioxygen by about 300-fold compared with analogous complexes of terphenyl carboxylate ([G-1]COO-) ligands. An FeIIFeIII intermediate was characterized
金属酶的活性位点通常深埋在疏水性蛋白质鞘内,保护它们免受不良水解和聚合反应的影响,使其发挥正常功能。为了模拟细菌单加氧酶活性位点的疏水环境,制备了通式 [Fe2([G-3]COO)4(4-RPy)2] 的二铁 (II) 化合物,其中 [G-3 ]COO-是第三代树枝状大分子附加的三联苯羧酸配体,4-RPy是吡啶衍生物。树枝状聚合物环境为二铁中心提供了极好的保护,与三联苯羧酸酯 ([G-1]COO-) 配体的类似配合物相比,其对分子氧的反应性降低了约 300 倍。FeIIFeIII 中间体通过电子、电子顺磁共振、穆斯堡尔、[Fe2([G-3]COO)4(4-PPy)2]氧化后的 X 射线吸收光谱分析,其中 4-PPy 是 4-吡咯烷并吡啶。结果与超氧物种的形成一致。这种二铁化合物在双氧存在下可以氧化外部底物。