State Key Laboratory of Supramolecular Structure and Materials, Jilin University, Changchun 130012, PR China.
Chemistry. 2011 Apr 4;17(15):4273-82. doi: 10.1002/chem.201002298. Epub 2011 Mar 4.
A series of surfactant-encapsulated and organically grafted polyoxometalates (SEOPs) were prepared through a co-precipitation procedure. Through a rational selection of the molecular components in the structure of the complex, SEOP complexes self-assemble into ordered aggregates with two different hierarchical self-assembled structures in an organic solvent mixture of dichloromethane and methanol in different volume ratios. FTIR, (1)H NMR, and X-ray photoelectron spectroscopy were used to characterize the self-assembly process and the involved driving forces. In a weakly polar solvent, SEOPs aggregated into fibers with a lamellar structure. When the solvent polarity was increased, SEOPs formed ribbonlike aggregates with a tetragonal structure. The change of the hierarchical self-assembled structure was deduced in regard to the arrangement of alkyl chains, electrostatic interactions, and hydrogen bonding between the pyridyl groups and terminal oxygen atoms of the polyoxometalates. The ribbonlike aggregates exhibit birefringence due to the ordered arrangement of SEOPs in the microstructure.
通过共沉淀法制备了一系列表面活性剂包裹和有机接枝的多金属氧酸盐（SEOP）。通过合理选择配合物结构中的分子组分，SEOP 配合物在二氯甲烷和甲醇的有机溶剂混合物中以不同的体积比自组装成具有两种不同层次自组装结构的有序聚集体。FTIR、（1）H NMR 和 X 射线光电子能谱用于表征自组装过程和涉及的驱动力。在弱极性溶剂中，SEOP 聚集成长有片状结构的纤维。当溶剂极性增加时，SEOP 形成具有四方结构的带状聚集体。根据烷基链的排列、静电相互作用以及吡啶基团和多金属氧酸盐末端氧原子之间的氢键，推断出层次自组装结构的变化。由于 SEOP 在微观结构中的有序排列，带状聚集体表现出双折射。
