Enhanced hydrolytic activity of Cu(ii) and Zn(ii) complexes in highly cross-linked polymers
作者:Alexander Schiller、Rosario Scopelliti、Kay Severin
DOI:10.1039/b605676h
日期:——
The chelate ligand tris[(1-vinylimidazol-2-yl)methyl]amine (5) was synthesized in five steps from commercially available starting materials. Upon reaction with ZnCl2 or CuCl2 in the presence of NH4PF6, the complexes [Zn(5)Cl]PF6 (6) and [Cu(5)Cl]PF6 (7) were obtained. The structure of both complexes was determined by single-crystal X-ray crystallography. Immobilization of 6 and 7 was achieved by co-polymerization with ethylene glycol dimethacrylate. The supported complexes P6-Zn and P7-Cu were found to be efficient catalysts for the hydrolysis of bis(p-nitrophenyl)phosphate (BNPP) at 50 °C. At pH 9.5, the heterogeneous catalyst P7-Cu was 56 times more active than the homogeneous catalyst 7. Partitioning effects, which increase the local concentration of BNPP in the polymer, are shown to contribute to the enhanced activity of the immobilized catalyst.
螯合配体三[(1-乙烯基咪唑-2-基)甲基]胺(5)由市售起始材料分五个步骤合成。在 NH4PF6 存在下与 ZnCl2 或 CuCl2 反应,得到配合物 [Zn(5)Cl]PF6 (6) 和 [Cu(5)Cl]PF6 (7)。两种配合物的结构均通过单晶X射线晶体学测定。 6和7的固定化是通过与乙二醇二甲基丙烯酸酯的共聚实现的。研究发现负载型配合物 P6-Zn 和 P7-Cu 在 50 °C 下是双(对硝基苯基)磷酸酯(BNPP)水解的有效催化剂。在 pH 9.5 时,多相催化剂 P7-Cu 的活性是均相催化剂 7 的 56 倍。分配效应可增加聚合物中 BNPP 的局部浓度,有助于提高固定化催化剂的活性。