Singha Asmita, Dey Abhishek
School of Chemical Science, Indian Association for the Cultivation of Science, Kolkata, India.
Chem Commun (Camb). 2019 May 9;55(39):5591-5594. doi: 10.1039/c9cc01423c.
To date, artificial dioxygen adducts of heme have not been demonstrated to be able to oxidize organic substrates in sharp contrast to their non-heme analogues and naturally occurring enzymes like heme dioxygenases. To address this apparent anomaly, an iron porphyrin complex is synthesized which includes a pendant quinol group. The corresponding dioxygen bound iron porphyrin species is demonstrated to perform hydrogen atom transfer (HAT) from the quinol group appended to the porphyrin ligand. The resultant ferric peroxide, formed by the first HAT, performs a 2nd HAT generating a ferryl species (FeIV[double bond, length as m-dash]O) and resulting in the 2e-/2H+ oxidation of the pendant hydroquinone to quinone.
迄今为止，与非血红素类似物和天然存在的酶（如血红素双加氧酶）形成鲜明对比的是，尚未证明血红素的人工双氧加合物能够氧化有机底物。为了解决这一明显的异常现象，合成了一种包含侧链喹啉基团的铁卟啉配合物。已证明相应的双氧结合铁卟啉物种可从连接到卟啉配体上的喹啉基团进行氢原子转移（HAT）。由第一次HAT形成的所得过氧化铁进行第二次HAT，生成高铁酰物种（FeIV═O），并导致侧链对苯二酚2e-/2H+氧化为醌。
