MAGNETIC CIRCULAR DICHROISM OF PORPHYRINS

作为过去二十年我们和其他实验室工作的结果 多年来，磁性圆二向色性(MCD)实际上已经成为一种基本的 卟啉及其相关化合物确证研究的光谱技术 蛋白质基质内外的大环，因为MCD可以提供 不可用或不容易访问的信息 其他方法。卟啉类化合物的MCD出现体征变异 提供了另一个重要的--但在很大程度上仍未探索--的焦点 MCD的应用，特别是在结构问题上。我们的主张 MCD以及相应的任何物质的吸收光谱 取代(乙烯基、烷氧基、甲酰基、乙酰基、氰基)卟啉 无论其数量、种类或相对方向如何 取代基，只有在光谱有限的情况下才能预测 已知与对称性相关的双取代卟啉的数量。我们建议 合成所需的二取代卟啉和其他 通过使用全合成程序来获得特定的卟啉 以游离碱和络合物的形式测量它们的光谱 金属离子。我们还建议详细阐述和发展理论 解释和预测光谱的模型将是 可供广泛的卟啉化学家使用--不仅仅是那些 在光谱和理论问题方面的专业知识。最后，由于MCD是 一个复杂的现象(由标量三重积之和所支配 由磁力耦合的所有状态的电矩和磁矩 场)，我们希望将MCD作为显式数值计算的焦点 旨在提供对电子状态的更完整的描述 取代的卟啉。

As a result of work in our and other laboratories over the past twenty years, magnetic circular dichroism (MCD) has become virtually an essential spectroscopic technique for definitive studies of porphyrins and related macrocycles both in and outside protein matrices since MCD can provide information that is either not available or is not as readily accessible by other methods. The occurrence of sign variation in the MCD of porphyrins provides a further important--but as yet largely unexplored--focus of applications of MCD, particularly to structural problems. Our proposition is that the MCD and, concomitantly, the absorption spectrum of any substituted (vinyl, alkoxycarbonyl, formyl, acetyl, cyano) porphyrin regardless of the number, kind, or relative orientations of the substituents, can be predicted provided only that the spectra of a limited number of symmetry related disubstituted porphyrins are known. We propose to synthesize the required sets of disubstituted porphyrins and other particular porphyrins through the use of total synthesis procedures and to measure their spectra as free-bases and as complexed with a limited number of metal ions. We also propose to elaborate and to develop theoretical models for the interpretation and prediction of spectra that will be accessible to a broad range of porphyrin chemists--not just to those with expertise in spectroscopic and theoretical problems. Finally, since MCD is a complex phenomenon (being governed by the sum of scalar triple products of electric and magnetic moments over all states coupled by the magnetic field), we hope to use MCD as a focus for explicit numerical calculations aimed at providing a more complete description of the electronic states of substituted porphyrins.