Research on Porphyrin-Chlorin Co-assemblies and Revival of Their Dioxygen-coordination Abilities Photoirradiation

本研究的目的是通过光照射共组装的自由碱氯或卟啉衍生物来恢复自氧化两亲性卟啉铁（III）（脂质卟啉铁（III））的二氧配位能力。第一年合成了一种具有4个类磷脂取代基的新型脂卟啉，它在水体系中易于分散和自组装，得到了直径为100nm的球形双层膜。所制备的脂质卟啉囊泡在生理条件下可以可逆地结合和释放二氧。红外光谱和MCD光谱显示了二氧的配位结构。还仔细测量了双氧结合亲和力和双氧缔合解离速率常数。第二年。研究了脂质卟啉双层膜中加入的原卟啉衍生物从激发态到铁（III）中心的电子转移过程。在外水相中电子供体（牺牲试剂）的共存下，该反应变为不可逆反应，即脂质卟啉铁（III）的光还原体系。在研究过程中，我们发现了一些与该项目相关的新现象。例如，在由锌（II）配合物和自由碱脂质卟啉组成的共组装双层囊泡中，卟啉锌（II）的单重态发生了高效的能量转移。这可能是一种新的水介质光收集模式。

The aim of this investigation is to revive the dioxygen-coordination ability of the auto-oxidized amphiphilic porphyrinatoiron(III) (lipidporphyrinatoiron(III)) by photoirradiation of the co-assembled free-base chlorine or porphyrin derivatives.In the first year, a new lipidporphyrin with four phospholipid-like substituents was synthesizes, It can be easily dispersed and self-assembled in aqueous system, to give spherical bi layer membranes with a diameter of 100 nm. The obtained lipidporphyrin vesicles can reversibly bind and release dioxygen under physiological conditions. The IR and MCD spectroscopies showed the coordination structure of the dioxygen. The dioxygen-binding affinity and dioxygen association and dissociation rate constants were also carefully measured.In the second year. electron transfer process from the excited state of the incorporated protoporphyrin derivative in the lipidporphyrin bilayer membrane to the iron(III) center was investigated. Under the co-existence of the electron donor (sacrificial regent) in outer aqueous phase, this reaction became irreversible, which is photoreduction system of the lipidporphyrinatoiron(III).During the research period, we found some new phenomena related on this project. For example, in co-assembled bi layer vesicles made of Zn(II) complex and free-base lipidporphyrins, high-efficient energy transfer took place from the singlet state of the porphyricatozinc(II). It could be a new light-harvesting model in aqueous medium.