In recent years, one of the research directions of proton-exchange membrane fuel cells (PEMFCs) was to exploit efficient electrocatalysts for oxygen reduction reaction (ORR) instead of precious metals. In this study, on the basis of the densityfunctional theory (DFT) calculations, we designed a new type of single-atom ORR electrocatalyst by doping single iron atoms into the N-coordination cavity of the substrate graphite carbonitride (Fe/g-C 3 N 4 ). The adsorption site and the adsorption energy of all the intermediates, the reaction energy barriers, potential energy surface, and Mulliken charges have been analyzed. The feasible ORR reaction paths and the most favorable ORR reaction mechanism were performed. Our calculation results prove that Fe/g-C 3 N 4 is a potential electrocatalyst toward ORR. This work proposes a novel notion for the development of cathode materials in PEMFCs.

Palladium-catalyzed asymmetric allylic substitution, due to its valuable reactive profile, has become a quite useful tool in organic synthesis fields. In the present study, density functional theory (DFT) calculations were applied to investigate the important factors for palladium-catalyzed 3-butene-2-ol and methylaniline amination reaction, with tetrahydrofuran (THF) as solvent. We find that this catalytic protocol results in high regio-and stereoselectivity, which is in line with the experimental result. According to our calculations, the high regio-and stereoselectivity is caused by the steric hindrance between the substrate and the catalyst ligand. To verify this point, we further explore the reactive process with different axial chirality on the catalyst ligand (altering the steric hindrance), and the results suggest that the preponderant R chiral configuration product has reversed. These results could lead to a better understanding of the mechanism for 3-butene-2-ol amination reaction and are helpful for the design of the corresponding catalyst ligand in the industry.

CYP2D6 is one of the most important metalloenzymes involved in biodegradation of many drug molecules in the human body. It has been found that multiple substrate binding can lead to...

Caffeine is a very common kind of nervous stimulant, and it is primarily metabolized by Cytochrome P450 1A2 (CYP1A2) in the human body. Over the years, determining the interactions between caffeine and CYP1A2 has been a tough issue. The active binding modes and the catalytic regioselectivity of the metabolism between CYP1A2 and caffeine remain unclear. Here, to investigate the interactions between CYP1A2 and caffeine, we constructed the all-sequence CYP1A2-caffeine-membrane system using a multiple template approach. According to our simulation results, four active binding modes between CYP1A2 and caffeine that correspond to the four metabolic sites of caffeine are determined. What is more, a pre-reaction state for the CYP1A2-catalyzed reaction at caffeine’s N3 site is identified. A more preponderant active binding mode might be the reason why the N3 site of caffeine becomes the primary metabolic site. Our findings could enhance our knowledge of the interactions between CYP1A2 and caffeine and help us better understand the regioselectivity of the metabolism between CYP1A2 and caffeine.