RAMAN STUDIES OF PORPHYRINS AND RELATED MACROCYCLES

拟议研究的总体目标是 卟啉类化合物的结构、电子和磁性， 氢卟啉和结构上相关的生物大环。一个 将使用包括共振拉曼在内的各种方法 (RR)、红外(IR)、吸收和电子顺磁共振 (EPR)光谱、法坐标分析和半经验 量子力场计算。程序、目标和 这些研究的理由如下： (1)各种典型氯素的RR和IR光谱， 细菌素和异活菌素的特性将在 细节。振动数据将通过两种方式进行分析 常规法坐标与半经验量子力 田野调查方法。半经验计算将得到改进， 扩展到蛋白质假体基团，如西罗血红素、血红素D1 和辅因子F430，它们不符合常规 振动分析程序，因为大量的 目前还没有同分异构体。这些研究的目的是 为振动数据的解释提供了基础 大体上是还原吡咯大环。这些基准是 需要(但不是普遍可用的)才能提取结构 氢卟啉的振动光谱中的信息 蛋白质。 (2)Pi-阳离子和Pi-阴离子的RR和IR光谱 将对各种卟啉和氢卟啉进行表征。 将对这些物种执行常规坐标计算 通过同时使用常规和半经验量子力场 方法：研究方法。不同还原金属的振动和EPR谱 氢卟啉，如铁(I)和镍(I)的络合物，也将 接受检查。这些研究的目的是描述 加成或引起的结构和电子微扰 电子的去除。对影响的定量评估 需要氧化/还原(但也不是普遍可用的) 为了从波谱中提取结构信息 蛋白质中氧化/还原的四聚吡咯中间体。 (3)一系列中性化合物的RR、IR、EPR和光谱。 氧化和还原的卟啉和氢卟啉二聚体以及 三聚体[结构Ln(环)2，(环)Ln(环‘)和Ln2(环)3]将 接受检查。这些研究的目的是确定 强PIPI相互作用对电子性质的影响 并为评估这些复合体如何 电子通信可能会传递能量和/或电子 蛋白质中四聚吡咯假体基团之间的转移。

The general objectives of the proposed research are to characterize the structural, electronic and magnetic properties of porphyrins, hydroporphyrins and structurally related bio-macrocycles. A variety of methodologies will be used including Resonance Raman (RR), infrared (IR), absorption and electron paramagnetic resonance (EPR) spectroscopies, normal coordinate analysis, and semiempirical quantum force field calculations. The procedures, aims and rationales for the studies are as follows: (1) The RR and IR spectra of a variety of prototypical chlorins, bacteriochlorins and isobacteriochlorins will be characterized in detail. The vibrational data will be analyzed via both conventional normal coordinate and semiempirical quantum force field methods. The semiempirical calculations will be refined and extended to protein prosthetic groups, such as siroheme, heme d1 and cofactor F430, which are not amenable to conventional vibrational analysis procedures because large numbers of isotopomers are not available. The aim of these studies is to provide a foundation for the interpretation of the vibrational data of reduced-pyrrole macrocycles in general. These bench marks are needed (but not generally available) in order to extract structural information from the vibrational spectra of hydroporphyrins in proteins. (2) The RR and IR spectra of pi-cation and pi-anion radicals of various porphyrins and hydroporphyrins will be characterized. Normal coordinate calculations will be performed on these species by using both conventional and semiempirical quantum force field methods. Vibrational and EPR spectra of various metal-reduced hydroporphyrins, such as complexes of Fe(I) and Ni(I), will also be examined. The aim of these studies is to characterize the structural and electronic perturbations induced by the addition or removal of electrons. A quantitative assessment of the effects of oxidation/reduction is needed (but again not generally available) in order to extract structural information from the spectra of oxidized/reduced tetrapyrrolic intermediates in proteins. (3) The RR, IR, EPR and optical spectra of a series of neutral, oxidized and reduced porphyrin and hydroporphyrin dimers and trimers [structure Ln(ring)2, (ring)Ln(ring') and Ln2(ring)3] will be examined. The aim of these studies is to determine the influence of strong pipi interactions on the electronic properties of the complexes and provide a foundation for assessing how such electronic communication might mediate energy and/or electron transfer between tetrapyrrolic prosthethic groups in proteins.