文献类型：期刊文献

英文题名：The secondary coordination sphere and axial ligand effects on oxygen reduction reaction by iron porphyrins: a DFT computational study

作者：Ohta, Takehiro[1,4];Nagaraju, Perumandla[2,4];Liu, Jin-Gang[3];Ogura, Takashi[1];Naruta, Yoshinori[2,4]

机构：[1]Univ Hyogo, Picobiol Inst, Grad Sch Life Sci, RSC UH LP Ctr, Mikazuki, Hyogo 6795148, Japan;[2]Chubu Univ, Inst Sci & Technol Res, Kasugai, Aichi 4878501, Japan;[3]East China Univ Sci & Technol, Dept Chem, Shanghai 200237, Peoples R China;[4]Kyushu Univ, Inst Mat Chem & Engn, Fukuoka 8128581, Japan

年份：2016

卷号：21

期号：5-6

起止页码：745

外文期刊名：JOURNAL OF BIOLOGICAL INORGANIC CHEMISTRY

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000382127000014)】；

基金：This work was financially supported by Scientific Research (C) (No. 24550080) and Scientific Research on Innovative Area (No. 25109535) to T.O. from JSPS and by the Elemental Science and Technology Project to Y.N. from the MEXT of Japan. NP thanks the Mitsubishi UFJ Trust Scholarship. JGL is grateful to the NSF of China (No. 21271072, 21571062), the Program for Professor of Special Appointment (Eastern Scholar) at Shanghai Institutions of Higher Learning.

语种：英文

外文关键词：Computational chemistry; Density functional theory; Dioxygen; Heme; Model compound; Porphyrin; Electrochemistry

摘要：Oxygen reduction reaction (ORR) catalyzed by a bio-inspired iron porphyrin bearing a hanging carboxylic acid group over the porphyrin ring, and a tethered axial imidazole ligand was studied by DFT calculations. BP86 free energy calculations of the redox potentials and pK (a)'s of reaction components involved in the proton coupled electron transfer (PCET) reactions of the ferric-hydroxo and -superoxo complexes were performed based on Born-Haber thermodynamic cycle in conjunction with a continuum solvation model. The comparison was made with iron porphyrins that lack either in the hanging acid group or axial ligand, suggesting that H-bond interaction between the carboxylic acid and iron-bound hydroxo, aquo, superoxo, and peroxo ligands (de)stabilizes the Fe-O bonding, resulting in the increase in the reduction potential of the ferric complexes. The axial ligand interaction with the imidazole raises the affinity of the iron-bound superoxo and peroxo ligands for proton. In addition, a low-spin end-on ferric-hydroperoxo intermediate, a key precursor for O-O cleavage, can be stabilized in the presence of axial ligation. Thus, selective and efficient ORR of iron porphyrin can be achieved with the aid of the secondary coordination sphere and axial ligand interactions.