PDF(Pubmed)
Abstract：
Isoporphyrins have recently been identified as remarkable species capable of turning the nucleophile attached to the porphyrin ring into an electrophile, thereby providing umpolung of reactivity (Inorg. Chem. 2022, 61, 8105-8111). They are generated by nucleophilic attack on an iron(III) π-dication, a class of species that has received scant attention. Here, we explore the effect of the porphyrin meso-substituent and report a iron(III) π-dication bearing the meso-tetraphenylporphyrin (TPP) ligand. We provide an extensive study of the species by UV/Vis absorption, 2 H NMR, EPR, applied field Mössbauer, and resonance Raman spectroscopy. We further explore the system\'s highly dynamic and tunable properties and address the nature of the axial ligands as well as the conformation of the porphyrin ring. The insights presented are essential for the rational design of catalysts for the umpolung of nucleophiles. Such catalytic avenues could for example provide a novel method for electrophilic chlorinations. We further examine the importance of electronic tuning of the porphyrin by nature of the meso-substituent as a factor in catalyst design.
摘要：
最近，已将异卟啉鉴定为能够将附着在卟啉环上的亲核试剂转化为亲电试剂的杰出物种。从而提供了反应性的增强(Inorg。Chem.2022、61、8105-8111）。它们是通过对铁（III）π指示的亲核攻击而产生的，一类很少受到关注的物种。这里,我们探索了卟啉内消旋取代基的作用，并报道了带有内消旋四苯基卟啉（TPP）配体的铁（III）π指示。我们通过UV/Vis吸收对物种进行了广泛的研究，2HNMR,EPR,应用领域Mössbauer，和共振拉曼光谱。我们进一步探索了该系统的高度动态和可调性质，并解决了轴向配体的性质以及卟啉环的构象。提出的见解对于合理设计用于增强亲核试剂的催化剂至关重要。这样的催化途径可以例如提供用于亲电氯化的新方法。我们进一步研究了通过内消旋取代基的性质对卟啉进行电子调谐的重要性，这是催化剂设计中的一个因素。
