Anthracene, oxygen-bridged

Anthranil (119) and benzyne (from oxidation of 9 with lead tetraacetate) afford acridine (5%)81 depending on the sequence of bond forming and breaking, an oxygen-bridged cycloadduct and/or acridine N-oxide (120) may be intermediates in this reaction (Scheme 15), although 120 is known to react with benzyne in a different sense (Section IX). The addition of benzyne to oxazoles leads, ultimately, to anthracene derivatives in high overall yield.82b... 

The oxo-bridged mixed-valent compound [(phen)2MnII,( -0)2Mn v(phen)2]3+, a model for part of the oxygen-evolving complex in photosystem II, oxidizes dihydroanthracene with high selectivity to anthracene.162... 

When the bridge itself contains a potential electron donor or acceptor, the situation can be more complex. Thus, Tsujiya et al. [15] studied the intramolecular electronic interaction between anthracene (An) and dimethylaniline (DMA) in bridged systems, when the bridge contained an ethereal oxygen. In these systems it was found that the appearance of exciplex emission depended strongly on the relative position of the ethereal oxygen with respect to the anthracene part of the molecule. For l-An-0-(CH2)2 DMA, one conformer was found to exhibit no exciplex emission at all in the jet, whereas another showed both locally excited and exciplex emission. For l-An-CH2-0 CH2-DMA (and also for 9-An-CH2-0-CH2-DMA), no exciplex emission was found in the jet, although the same molecules show exciplex emission in solution It appears that the interaction between... 

Bridged Peroxides.—Routine procedures have been extended to the synthesis and characterization of photo-adducts of singlet oxygen with cyclo-octa-1,3,5-triene, cycloheptatrienes, 3,5-cycloheptadienone, cyclohepta-1,3-dienes, ° naphthalenes, anthracenes, a-pyrones, pyrazines and pyrimidines,imidazoles, and indenes. Transformation of some of these... 

Figure 2.20. The anthracene-bridged binuclear Ru"/Os" complex and the corresponding oxygenated product.

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