Azobenzene, transfer hydrogenation with

Hydrogen transfer from a phenyl group to nitrogen is observed in the photochemical formation of (21) from azobenzene and Fe(CO)s 24>. It appears not impossible, that intermediates with Fe— H bonds are involved in this reaction. 

The conclusion from all observations is that the Grignard reagents transfer magnesium to azo-henzene to produce a radical pair in a stepwise mechanism. The transfer, however, takes place in a transition siale which is very similar to the concerted six-centre Whitmore Mosher complex and has rather strict steric requirements. The reaction is radical-concerted. This, lor example, explains that in the reaction of x-hulylmagncsinm bromide with azobenzene, l-hinene is formed in a 4 1 ratio relative lo 2-huiene. while this ratio in reactions with other electron acceptors is below unity. Since the radical pail is formed with a conformation which is ideal for transfer of /I-hydrogen this is the main product, but the radicals... 

Hydrogen transfer from hydrazobenzene to benzofuroxan (622) results in azobenzene and o-benzoquinone dioxime (623). Compound (622) reacts with formaldehyde to yield the benzimidazolinone (624). Chlorobenzofuroxan aldehyde condenses with derivatives of hydroxylamine or hydrazine to yield oximes or hydrazones (625 R = OH, OMe, NHPh, NMe2, etc.), which rearrange thermally to indazoles (626). Treatment of 7-methoxy-4-nitro-benzofurazan 1-oxide with aqueous potassium hydroxide affords a mixture of the corresponding 7-hydroxy-compound (627) and the rearranged 5-hydroxy-4-nitrobenzofuroxan (628). ... 

To study the vibrational energy relaxation of the amide I mode in N-methylacetamide, we employed the OPLS all-atom force field to model the solute and the flexible simple-point-charge (SPC) water modeF with doubled hydrogen masses to model the solvent D2O. To investigate the photoinduced heat transfer in photoswitchable peptides, we used the GROMOS96 united atom force field 43al. Additional force field parameters for the azobenzene unit were derived from density functional theory as described in Ref. [32]. We employed a united-atom modeP to describe the DMSO solvent, the SPC modeP to describe water, and the rigid all-atom model of Ref [57] to describe the chloroform solvent. 

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