Conversion of Electron Configuration of Iron Ion through Core Contraction of Porphyrin: Implications for Heme Distortion

It was demonstrated experimentally that nonplanar iron porphyrins can be induced to undergo a conversion in their electronic configuration to form a cross-hybrid transition by compressing the macrocyclic core size for the central metal ion. A series of monostrapped iron porphyrins were used as model systems, and their electronic properties were probed using electron spin resonance and differential spectral analyses. These results indicate that the formation of a cross-hybrid transition stage is related to the stability of the high-valence state and potent oxidizing ability of the central iron ion.

本研究经实验证实：通过压缩中心金属离子的大环核尺寸，可诱导非平面铁卟啉（nonplanar iron porphyrins）发生电子构型转变，形成交叉杂化跃迁（cross-hybrid transition）。本研究采用一系列单桥联铁卟啉（monostrapped iron porphyrins）作为模型体系，借助电子自旋共振（electron spin resonance）与差示光谱分析对其电子性质进行了表征。结果表明，交叉杂化跃迁阶段的形成与中心铁离子的高价态稳定性及强氧化能力密切相关。