Hydrogen atom abstraction

In chemistry, hydrogen atom abstraction, or hydrogen atom transfer (HAT), refers to a class of chemical reactions where a hydrogen free radical (a neutral hydrogen atom) is removed from a substrate, another molecule. This process follows the general equation:

${\displaystyle {\ce {X^{\bullet }{}+H-Y->X-H{}+Y^{\bullet }}}}$

HAT reactions are common in various redox reactions, hydrocarbon combustion, and interactions involving cytochrome P450 that contain an Fe(V)O unit. The entity removing the hydrogen atom, known as the abstractor (X•), is often a radical itself, though in some instances, it may be a species with a closed electron shell, such as chromyl chloride. Hydrogen atom transfer can occur via a mechanism known as proton-coupled electron transfer. An illustrative synthetic instance of HAT is observed in iron zeolites, which facilitate the stabilization of alpha-oxygen.^[1][2]

References

1. Snyder, Benjamin E. R.; Vanelderen, Pieter; Bols, Max L.; Hallaert, Simon D.; Böttger, Lars H.; Ungur, Liviu; Pierloot, Kristine; Schoonheydt, Robert A.; Sels, Bert F. (August 2016). "The active site of low-temperature methane hydroxylation in iron-containing zeolites". Nature. 536 (7616): 317–321. Bibcode:2016Natur.536..317S. doi:10.1038/nature19059. ISSN 0028-0836. PMID 27535535. S2CID 4467834.
2. Snyder, Benjamin E. R.; Bols, Max L.; Schoonheydt, Robert A.; Sels, Bert F.; Solomon, Edward I. (2017-12-19). "Iron and Copper Active Sites in Zeolites and Their Correlation to Metalloenzymes". Chemical Reviews. 118 (5): 2718–2768. doi:10.1021/acs.chemrev.7b00344. ISSN 0009-2665. PMID 29256242.