Fabrication of inorganic-organic hybrid compounds possessing a specific hydrophobic space

在本研究中，研究了具有特定疏水空间的无机-有机杂化化合物的制备。从实验化学、物理化学和理论化学的角度进行了研究，发现(1)支撑配体的空间体积、(2)桥接配体的长度和刚性、(3)溶剂的作用等因素是控制阳离子过渡金属（钯）配合物与有机桥接配体组成的超分子结构的前提。基于这些对超分子的认识，合成了具有120°角桥接配体的新型分子六边形。由于分子六边形与分子菱形平衡，这些分子的单独合成也通过调节支撑配体和一种溶剂的空间体积来完成。特别是从分子六边形的x射线晶体学来看，它具有直径约1.35 nm的特征性疏水腔，并且分子六边形在晶格中的排列形成了沿c轴的管状通道。然后，将反阴离子放置在阳离子钯中心附近和疏水腔外。因此，可以通过去除腔内的结晶溶剂来期望客体包合能力。随后，用直径约为1 nm的keggin型多金属氧酸盐考察了分子六边形的客体包合能力。核磁共振（NMR）和扩散有序谱（DOSY）显示了多金属氧酸盐在分子六边形腔内的包封。这些结果为利用超分子实现多金属氧酸盐功能化的新方法铺平了道路，并为制备具有超大疏水空间的无机-有机杂化化合物提供了新方法。

In this study, the fabrication of inorganic-organic hybrid compounds possessing a specific hydrophobic space was investigated. The researches from the view points of the experimental chemistry, physical chemistry, and theoretical chemistry revealed that these factors, such as (1) the steric bulkiness of the supporting ligand, (2) the length and rigidity of the bridging ligand, and (3) the effect of solvent, are prerequisite for the control of the supramolecular structures consisting of the cationic transition metal (palladium) complexes and the organic bridging ligands. Based on these insights into supramolecules, the synthesis of the novel molecular hexagon with a 120° angular bridging ligand was attained. Since the molecular hexagon equilibrates with the molecular rhomboid, the separate syntheses of these molecules were also accomplished by tuning the steric bulkiness of the supporting ligand and a kind of solvent. Particularly from X-ray crystallography of the molecular hexagon, it possesses the characteristic hydrophobic cavity with the diameter of ca. 1.35 nm and that the array of the molecular hexagon in the crystal lattice creates the tubular channel along c-axis. Then, the counter anions were positioned near the cationic palladium center and outside of the hydrophobic cavity. Therefore, the guest inclusion ability might be expected by the removal of the solvents of crystallization inside the cavity.Successively, the guest inclusion ability of the molecular hexagon was investigated using Keggin-type polyoxometalate with the diameter of ca. 1 nm. The nuclear magnetic resonance (NMR) spectrum with the diffusion ordered spectroscopy (DOSY) revealed the encapsulation of polyoxometalate inside the cavity of molecular hexagon. These results pave the way for the novel method for the functionalization of polyoxometalate by the supramolecule and lead to the novel method for the fabrication of inorganic-organic hybrid compound with the extra large hydrophobic space.