Rosaria Lauceri, D'urso Alessandro, Mammana Angela, Purrello Roberto
CNR, Istituto di Biostrutture e Bioimmagini-Sezione di Catania, 95125 Catania, Italy.
Chirality. 2008 Mar;20(3-4):411-9. doi: 10.1002/chir.20464.
The interaction between the tetra-anionic porphyrin H2TPPS and its copper derivative, CuTPPS, with the tetra-cationic porphyrin H2T4 and its copper derivative, CuT4, leads, in aqueous solution, to the formation of remarkably stable and kinetically inert heteroaggregates. The aggregation process is under hierarchic control and, in the presence of a suitable chiral mold, leads to the formation of chiral porphyrin heteroassemblies as stable and inert as the achiral ones. Because of these properties, the chirality of the porphyrin "imprinted" heteroaggregates not only survives the disruption of the template, but also to its complete removal from the solution. Notably, the template-free chiral porphyrin system is an excellent mold for its own self-replication. The relevant characteristics of these chiral heteroaggregates together with the knowledge of the forces that guide the aggregation processes permitted us to design a new but similar system. This system not only is able to store chiral information, but also is capable to release and restore it reversibly, in a cyclic manner. This has been achieved by modulating the charges carried by one of the two coupled porphyrins through protonation under various pH conditions. The role of the central metal ion and the template-free chiral structure of the CuT4-H2TPPS heteroaggregate, determined through EDXD analysis, are also presented.
四阴离子卟啉H2TPPS及其铜衍生物CuTPPS与四阳离子卟啉H2T4及其铜衍生物CuT4之间的相互作用，在水溶液中会导致形成非常稳定且动力学惰性的杂聚体。聚集过程受层次控制，并且在合适的手性模板存在下，会导致形成与非手性杂聚体一样稳定和惰性的手性卟啉杂组装体。由于这些特性，卟啉“印记”杂聚体的手性不仅在模板破坏后得以保留，而且在模板从溶液中完全去除后仍能保留。值得注意的是，无模板手性卟啉体系是其自身自我复制的优良模板。这些手性杂聚体的相关特性以及对引导聚集过程的作用力的了解，使我们能够设计出一个新的但类似的体系。该体系不仅能够存储手性信息，还能够以循环方式可逆地释放和恢复手性信息。这是通过在各种pH条件下通过质子化调节两个偶联卟啉之一所携带的电荷来实现的。还介绍了通过EDXD分析确定的CuT4-H2TPPS杂聚体的中心金属离子的作用和无模板手性结构。
