Kanzaki Chisako, Yoneda Hiroshi, Nomura Shota, Maeda Takato, Numata Munenori
Department of Biomolecular Chemistry, Graduate School of Life and Environmental Sciences, Kyoto Prefectural University Shimogamo, Sakyo-ku Kyoto 606-8522 Japan
RSC Adv. 2022 Oct 26;12(47):30670-30681. doi: 10.1039/d2ra05542b. eCollection 2022 Oct 24.
We have synthesized novel water-soluble anionic porphyrin monomers that undergo pH-regulated ionic supramolecular polymerization in aqueous media. By tuning the total charge of the monomer, we selectively produced two different supramolecular polymers: J- and H-stacked. The main driving force toward the J-aggregated supramolecular polymers was the ionic interactions between the sulfonate and protonated pyrrole groups, ultimately affording neutral supramolecular polymers. In these J-aggregated supramolecular polymers, amide groups were aligned regularly along polymer wedges, which further assembled in an edge-to-edge manner to afford nanosheets. In contrast, the H-aggregated supramolecular polymers remained anionic, with their amide NH moieties acting as anion receptors along the polymer chains, thereby minimizing repulsion. For both polymers, varying the steric bulk of the peripheral ethylene glycol (EG) units controlled the rates of self-assembly as well as the degrees of polymerization. This steric effect was further tunable, depending on the solvation state of the EG chains. Accordingly, this new family of supramolecular polymers was created by taking advantage of unique driving forces that depended on both the pH and solvent.
我们合成了新型水溶性阴离子卟啉单体，其在水性介质中会发生pH调节的离子超分子聚合反应。通过调节单体的总电荷，我们选择性地制备了两种不同的超分子聚合物：J-堆积和H-堆积的聚合物。形成J-聚集超分子聚合物的主要驱动力是磺酸根与质子化吡咯基团之间的离子相互作用，最终得到中性超分子聚合物。在这些J-聚集的超分子聚合物中，酰胺基团沿着聚合物楔子规则排列，这些聚合物楔子进一步以边对边的方式组装形成纳米片。相比之下，H-聚集的超分子聚合物保持阴离子性质，其酰胺NH部分沿聚合物链充当阴离子受体，从而使排斥作用最小化。对于这两种聚合物，改变外围乙二醇（EG）单元的空间体积可控制自组装速率以及聚合度。这种空间效应可进一步调节，这取决于EG链的溶剂化状态。因此，通过利用依赖于pH和溶剂的独特驱动力，创建了这个新的超分子聚合物家族。
