XAS STUDIES OF CPD I INTERMEDIATES

我们收集了11个铁卟啉的Fe K-Edge XAS光谱 化合物和CPD I模型[FeIV=O(TMP*)]，以便将 1s&gt；3D前缘的强度和多重态分裂图案 区域与铁位置的几何结构和电子结构有关。 所研究的铁卟啉可分为四类：(1) 6坐标(低旋)S=1/2；(2)5坐标(高旋)S=5/2；(3) 5坐标(自旋混合)S=5/2-3/2；(4)6坐标(自旋 混合)S=5/2-3/2。我们的结果最终表明 观察到的前缘特征的强度是这些特征的诊断 四节课。对6个坐标进行详细的多重分析， 低自旋配合物[FeTMBPP]Cl已允许进行实验 单电子铁配位体场态能量的测定。至 我们的知识，这代表着第一次直接测量 铁卟啉的配位场参数。有趣的是， 前边缘区域的信息内容是对其的补充 可通过电子顺磁共振波谱获得。这些方法的推广 应考虑到详细的几何和电子结构 关于EPR沉默的亚铁卟啉的信息。

We have collected Fe K-Edge XAS spectra for 11 ferric porphyrin compounds and the cpd I model [FeIV=O(TMP*)]+ in order to relate the intensity and multiplet splitting pattern of the 1s->3d pre-edge region to the geometric and electronic structure of the iron site. The ferric porphyrins studied fall into four categories: (1) 6-coordinate (low-spin) S=1/2; (2) 5-coordinate (high-spin) S=5/2; (3) 5-coordinate (spin admixed) S=5/2-3/2; (4) 6- coordinate (spin admixed) S=5/2-3/2. Our results conclusively show that the integrated intensity of the observed pre-edge features is diagnostic of these four classes. A detailed multiplet analysis of the 6-coordinate, low-spin complex [FeTMBPP]Cl has allowed for an experimental determination of the one-electron Fe ligand field state energies. To our knowledge, this represents the first direct measurement of the ligand field parameters for a ferric porphyrin. Interestingly, the information content of the pre-edge region is complementary to that obtainable by EPR spectroscopy. Extension of these methodologies should allow for detailed geometric and electronic structural information to be obtained on EPR silent ferrous porphyrins.