Redox intramolecular

The oxidation of 1-nitronaphthalene by ceric ammonium nitrate has been reported (16). The resulting 1-iiitronaphthoquinone condenses with 1,3-butadiene followed by air oxidation under alkaline conditions to form 1-nitroanthraquinone, or l-aminoanthraquinone is formed direcdy by an intramolecular redox reaction. 

A useful approach to the substitution of ring C—H positions lies in the activation of the heteroaromatic system by an A-oxide group, initiating a formal intramolecular redox reaction. 1-Methyllumazine 5-oxide reacts with acetic anhydride in a Katada rearrangement... 

Disiloxane, tetramesityl-, 3,206 Disproportionation iridium catalysts, 4,1159 Dissolution nuclear fuels, 6, 927 Distannene, 3,217 Distannoxane, 1,3-dichloro-, 3,207 Distibine, tetraphenyl-, 2,1008 Distibines, 2,1008 Disulfido ligands metal complexes, 2,531-540, 553 bonding, 2, 539 electron transfer, 2, 537 intramolecular redox reactions, 2,537 reactions, 2, 537... 

This considerable enhancement in redox properties may however remain chemically hidden. Several causes may converge to mask these properties. First of all electron transfer is an intermolecular act of reactivity even when thermodynamically feasible it may have to compete with very rapid intramolecular acts of deactivation (fluorescence, phosphorescence, internal conversion)99. The rate of electron transfer is given by the Rehm-Weller equation96,100... 

We will use here the main results obtained for two complex and distinct situations the structural and spectroscopic information gathered for D. gigas [NiFe] hydrogenase and AOR, in order to discuss relevant aspects related to magnetic interaction between the redox centers, intramolecular electron transfer, and, finally, interaction with other redox partners in direct relation with intermolecular electron transfer and processing of substrates to products. 

Thiocarbamate (tc, RHNCSO-) is a monodentate ambidentate ligand, and both oxygen- and sulfur-bonded forms are known for the simple pentaamminecobalt(III) complexes. These undergo redox reactions with chromium(II) ion in water via attack at the remote O or S atom of the S- and O-bound isomers respectively, with a structural trans effect suggested to direct the facile electron transfer in the former.1045 A cobalt-promoted synthesis utilizing the residual nucleophilicity of the coordinated hydroxide in [Co(NH3)5(OH)]2+ in reaction with MeNCS in (MeO)3PO solvent leads to the O-bonded monothiocarbamate, which isomerizes by an intramolecular mechanism to the S-bound isomer in water.1046... 

Nitroethane undergoes base-catalyzed addition to C60 to give 2-hydroxy-1,2-dihydrofulleryl ketoxime by way of a unique intramolecular redox process, which is not observed in normal electron deficient alkenes (Eq. 8.77).128 (See Section 4.3 Michael addition of nitroalkanes). 

Effective charge and transition-state structure in solution, 27, 1 Effective molarities of intramolecular reactions, 17,183 Electrical conduction in organic solids, 16,159 Electrochemical methods, study of reactive intermediates by, 19, 131 Electrochemical recognition of charged and neutral guest species by redox-active receptor molecules, 31, 1... 

Upon further contact with a redox reagent or at higher redox potentials, additional electrons can be transferred. After a two-electron transfer, each redox unit can accept one charge with formation of a singlet or triplet dianion, or (less favourably from an electrostatic point of view) both charges can enter one redox unit. Here again, an intramolecular electron-exchange process is possible. 

These structural factors are relevant for the redox-activity of bis- and oligo-electrophoric systems and for the reorganization energy associated with intramolecular electron hopping. 

The rate of degenerate intramolecular electron-transfer processes in biselectrophoric redox systems, and the observed spin-density distribution over one or two units depend upon the overall reorganization energy and thus upon... 

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