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The hydroxyl radical, • HO, is the neutral form of the hydroxide ion (HO –). Hydroxyl radicals are highly reactive and consequently short-lived; however, they form an important part of radical chemistry .
Reactive oxygen species or ROS are species such as superoxide, hydrogen peroxide, and hydroxyl radical, commonly associated with cell damage. ROS form as a natural by-product of the normal metabolism of oxygen and have important roles in cell signaling. Two important oxygen-centered radicals are superoxide and hydroxyl radical. They derive from ...
Some prominent ROS are hydroperoxide (O 2 H), superoxide (O 2-), [1] hydroxyl radical (OH.), and singlet oxygen. [2] ROS are pervasive because they are readily produced from O 2, which is abundant. ROS are important in many ways, both beneficial and otherwise. ROS function as signals, that turn on and off biological functions.
Hydroxyl radicals are produced with the help of one or more primary oxidants (e.g. ozone, hydrogen peroxide, oxygen) and/or energy sources (e.g. ultraviolet light) or catalysts (e.g. titanium dioxide). Precise, pre-programmed dosages, sequences and combinations of these reagents are applied in order to obtain a maximum •OH yield.
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula −OH and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry , alcohols and carboxylic acids contain one or more hydroxy groups.
ROS are reduced oxygen intermediates that include the superoxide radical (O 2 −) and the hydroxyl radical (OH•), as well as the non-radical species hydrogen peroxide (H 2 O 2). These ROS are important in the normal functioning of cells, playing a role in signal transduction [1] [2] and the expression of transcription factors.
Haber, Wilstätter and Weiss simply wrote HO 2 or O 2 H, but sometimes HO 2 • or • O 2 H can also be found to stress the radical character of the species. The hydroperoxyl radical is a weak acid and gives rise to the superoxide radical (O 2 •–) when it loses a proton: HO 2 → H + + O 2 – sometimes also written as: HO 2 • → H ...
Ultimately, both reactions generate hydroxyl radicals. These radicals are oxidative in nature and nonselective with a redox potential of E 0 = +3.06 V. [24] This is significantly greater than many common organic compounds, which typically are not greater than E 0 = +2.00 V. [25] This results in the non-selective oxidative behavior of these ...