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Hydrogen atom abstraction
About: Hydrogen atom abstraction is a research topic. Over the lifetime, 7059 publications have been published within this topic receiving 151781 citations.
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TL;DR: In this paper, the success or failure of the Norrish type II reaction for a series of compounds in the crystalline state with geometric data derived from X-ray crystallography (the so-called Crystal Structure-Solid State Reactivity Method) was analyzed.
96 citations
TL;DR: In this article, a trihydridoruthenium(IV) complex was obtained by treating RuH2(H2)2(PCy3)2 with 3 equiv of an alkene bearing σ-donor substituents such as CH2CH(SiEt3)/CH2CHtBu.
96 citations
TL;DR: In this paper, the authors investigated the photooxidation of alkanes, alkenes, alcohols, and aldehydes by molecular oxygen in aqueous solution and showed that all the reactions take place by hydrogen atom abstraction from C-H bonds, followed by uranium-mediated product formation.
Abstract: Uranium(VI) catalyzes the photooxidation of alkanes, alkenes, alcohols, and aldehydes by molecular oxygen in aqueous solution. Despite the mechanistic complexities, each of there actions investigated yielded a single organic product. On the basis of the quenching kinetics, the deuterium isotope effects, the nature of the products, and linear free energy relationships, all the reactions appear to take place by hydrogen atom abstraction from C-H bonds, followed by uranium-mediated product formation.
95 citations
TL;DR: In this paper, the photoreduction of benzophenone (BP) takes place in the interlayer between the LDPE films, and is a three-stage process: surface photoresduction, secondary photoresuction, and solid-state photoresde.
Abstract: A bulk surface photografting process which is conducted in the interface between two polymer films was designed and investigated. The bulk surface photografting is a highly efficient process. With this method, the surface of hydrophobic polymers can be made hydrophilic in less than 2 s and a grafted layer 5 μm thick can be obtained in 30 s. The kinetic investigation shows that the bulk surface photografting polymerization involves a four-step reaction process: induction period, surface initiation, successive polymerization, involves a four-step reaction process: induction period, surface initiation, successive polymerization, and solid-phase crosslinking. The photoreduction of benzophenone (BP) takes place in the interlayer between the LDPE films and is a three-stage process: surface photoreduction, secondary photoreduction, and solid-state photoreduction. With regard to the photoreduction of the initiator caused by hydrogen abstraction, the kinetic studies show that the photoreduction rate has a first-order dependence on the BP concentration. The activation energy of the hydrogen abstraction reaction is about 28.5 KJ (6.8 kcal)/mol. With regard to the photografting polymerization reaction, the reaction order of the rate Rp with respect to the monomer is unity and 0.89 with respect to BP. This means that the termination reaction takes place mainly by combination of polymer chain free radicals and semipinacol free radicals from BP. The activation energy of the overall polymerization reaction is around 8.8 kJ (2.1 kcal)/mol. © 1996 John Wiley & Sons, Inc.
95 citations
TL;DR: It is suggested that the large difference in optimal size (as determined in gas phase) of the complex, before and after the O-O bond cleavage, leads to an additional driving force for the reaction, not considered previously.
Abstract: Several new aspects of the O-O bond cleavage and alkane hydroxylation mechanisms have been studied by hybrid density functional theory in this reinvestigation of methane monooxygenase. As concerning key intermediates in these reactions, a new important low-lying state is found, described either as Fe2(III,V) or as Fe2(III,IV)O. A fully optimized transition state for O-O bond cleavage has been determined. It is suggested that the large difference in optimal size (as determined in gas phase) of the complex, before and after the O-O bond cleavage, leads to an additional driving force for the reaction, not considered previously. The strain of the enzyme is estimated to lead to a driving force in the forward direction of about 5 kcal/mol, which could explain some of the pH dependence found in recent experiments. For the hydroxylation reaction, a clean hydrogen abstraction transition state leading to a substrate radical is again found, in contrast to interpretations of radical clock experiments. An explanation, based on new results, is suggested that could account for both the experimental and theoretical results.
95 citations