Hydrogen detachment

Sobolewski AL, Domcke W, Dedonder-Lardeux C, Jouvet C (2002) Excited-state hydrogen detachment and hydrogen transfer driven by repulsive (l)pi sigma states a new paradigm for nonradiative decay in aromatic biomolecules. J Phys Chem Chem Phys 4 1093—1100... 

Pathways of Hydrogen Detachment from Anion-Radicals... 

Photoinduced Hydrogen Detachment from Aromatic Chromophores... 

The UV photochemistry of phenol and related systems (such as indole, pyrrole, imidazole) is dominated by a hydrogen detachment reaction which is driven by repulsive 1ira states [33,35 10], For the isolated chromophores, the 1 mr -driven photodissociation has been explored in unprecedented detail by high-resolution photofragment translational spectroscopy [40], The OH (or NH) bond is broken homolytically, resulting in the formation of two radical species, the hydrogen atom and the phenoxy (or indolyl, etc.) radical. Ion pair formation (abstraction of protons) is energetically not feasible for isolated photoacids. 

Fig. 8 Transition state of the planar B12H/ (2) either to icosahedral B 2H (1) or to planar B12H/ (3) structures. Hydrogen detachment of icosahedral BjoH (4) leads to planar Bjo...

The electron-withdrawing ability of the functional group also determines the stability of the carbanion by helping to delocalize the negative charge generated upon hydrogen detachment. 

Shemesh D, Sobolewski AL, Domcke W (2010) Role of excited-state hydrogen detachment and hydrogen-transfer processes for the excited-state deactivation of an aromatic dipeptide N-acetyl tryptophan methyl amide. Phys Chem Chem Phys 12 4899... 

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