SYNTHESIS AND PHOTOCHEMISTRY OF SUBSTITUTED PORPHYRINS

我们的长期目标是开发合成方法， 生物有机分子，可以用来提供洞察关系， 分子结构和生物功能之间的联系 我们已经开发了一种室温仿生合成 四苯基卟啉，产率60%。 我们将扩大这一范围 制备卟啉的方法，这在以前是无法获得的。 这包括中位烷基卟啉类，其中一些应该是 极溶于脂质介质。 两亲性卟啉然后可以被 准备用于双层研究。 然后，我们将利用这种新的方法， 高收率合成含卟啉的共面二聚体， 氯 我们计划对电子相互作用进行广泛研究 由环的并置产生。 为了模拟光收集 光合作用装置，我们将设计和合成卟啉 带有大体积的取代基，这些取代基在结晶状态下将保持 以固定的距离分开。 应用中的荧光测量 电场应该提供数据来区分能量的机制 转移 这些新合成的卟啉应该具有相当大的价值 在扩展我们对血红素和叶绿素性质的理解方面， 生物系统。 生物有机化学中一个更具有全局性的问题是模型的合成 具有明确定义的三维结构的系统。 我们建议开设 包含供体的光合过程的模块化模型系统 和受体以堆叠几何结构共价连接。 间隔基团 将供体和受体分开由对氨基苯甲酸亚基组成， 它们以类似于肽的逐步方式偶联在一起， DNA合成 5、10和15 A的三种卟啉-醌化合物 将制备在其间隔区中具有1、2和3个亚基的分离 组 这类分子的光化学特性 将提供一个系统的研究距离对电子 转移反应 这种模块化方法应具有广泛的适用性 在生物有机领域。

Our long-term objectives are to develop synthetic methods for creating bioorganic molecules which can be used to provide insight into the relation between molecular structure and biological function. We have developed a room temperature biomimetic synthesis of tetraphenyl-porphyrin in 60% yield. We will expand the scope of this methodology to prepare porphyrins which have previously been unobtainable. This includes the class of meso-alkylporphyrins, some of which should be extremely soluble in lipid media. Amphipathic porphyrins can then be prepared for bilayer studies. Then we will exploit this new methodology in the high yield synthesis of cofacial dimers containing porphyrins and chlorins. We plan an extensive study of the electronic interactions resulting from the juxtaposition of rings. To model the light harvesting apparatus of photosynthesis, we will design and synthesize porphyrins bearing bulky substituents which in the crystalline state will hold the porphyrins at fixed distances apart. Fluorescence measurements in applied electric fields should provide data to distinguish the mechanisms of energy transfer. These new synthetic porphyrins should be of considerable value in extending our understanding of the properties of heme and chlorophyll in biological systems. A more global problem in bioorganic chemistry is the synthesis of model systems having well-defined 3-dimensional structures. We propose to create modular model systems of the photosynthetic process which contain a donor and acceptor covalently linked in a stacked geometry. The spacer groups separating the donor and acceptor are composed of p-aminobenzoic subunits, which are coupled together in a stepwise manner analogous to peptide and DNA synthesis. Three porphyrin-quinone compounds of 5, 10, and 15 A separation will be prepared which have 1, 2, and 3 subunits in their spacer groups. The photochemical characterization of this family of molecules will provide a systematic study of the effect of distances on electron transfer reactions. This modular approach should have broad applicability in the bioorganic field.