Molecular Complexes of Water-Soluble Porphyrins

Water-soluble porphyrins tend to form self-aggregates under certain conditions. The structure of the self-aggregate (H-type dimer, H-type higher aggregate, or J-aggregate) sensitively depends on the structure of the peripheral substituents at the meso-positions of the porphyrin. Water-soluble porphyrins also form relatively stable π-stacked complexes with various aromatics. Polar effects are important in complexation of anionic porphyrins with anthraquinonesulfonates. The results suggest that the main attractive interaction for formation of π-stacked complexes of water-soluble porphyrins is the σ-π interaction as claimed by Hunter and Sanders. Meanwhile, the aryl groups at the meso-positions of the water-soluble porphyrins are included by per-O-methylated β-cyclodextrin through van der Waals interactions to form extremely stable 1:2 complexes (porphyrin:cyclodextrin). Such a character of the water-soluble porphyrins can be applied to convenient preparation of supramolecular hetero-porphyrin arrays.

水溶性卟啉在某些条件下往往会形成自聚集体。自聚集体的结构（H型二聚体、H型高级聚集体或J聚集体）敏感地取决于卟啉中位周边取代基的结构。水溶性卟啉还会与各种芳香族化合物形成相对稳定的π - 堆积复合物。极性效应在阴离子卟啉与蒽醌磺酸盐的络合过程中很重要。研究结果表明，水溶性卟啉形成π - 堆积复合物的主要吸引力相互作用是亨特和桑德斯所提出的σ - π相互作用。同时，水溶性卟啉中位的芳基通过范德华相互作用被全 - O - 甲基化β - 环糊精包合，形成极其稳定的1∶2复合物（卟啉∶环糊精）。水溶性卟啉的这种特性可应用于超分子杂卟啉阵列的便捷制备。