Photochemical transformations. 37. Electron-transfer requirements for photosolvolysis and photo-Wagner-Meerwein reactions of some dichlorodibenzobicyclo(2. 2. 2)octadienes in singlet and triplet excited states
Substituted trans-7,8-dichloro-10-X-2,3:5,6-dibenzobicyclo(2.2.2)octa-2,5-dienes (X = COCH/sub 3/, CN, and NO/sub 2/) and corresponding dinitro-substituted compounds (10,15-dinitro) were solvolyzed with silver acetate in acetic acid and were irradiated in glacial acetic acid or acetonitrile with 254- and 300-nm light. The structures of the monoring-substituted diastereoisomeric dichlorides were demonstrated by proof of structures of the daughter solvolysis products. Unlike compounds previously studied, these compounds were either photochemically inert or photoinactive with respect to Wagner-Meerwein rearrangement or to solvolysis. These results have been rationalized in terms of the inability of the excited states of the light-absorbing chromophores in these compounds to transfer electrons to the carbon-chlorine bonds remote from these chromophores. While triplet states of a variety of cis- and trans-7,8-dichloro-2,3:5,6-dibenzobicyclo(2.2.2)octa-2,5-dienes are reported to be similarly inert, the 10,11-dimethoxy derivatives all were photoactive with acetone sensitization. The migration stereochemistries of the sensitized reactions were quite different from those of direct irradiations or of ground-state reactions. Estimations of the free energies of electron transfer were consistent with these and previously reported results. 26 references, 1 table.
- Research Organization:
- Univ. of Colorado, Boulder
- DOE Contract Number:
- AC02-79ER10366
- OSTI ID:
- 6611765
- Journal Information:
- J. Org. Chem.; (United States), Vol. 49:13
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CYCLOALKENES
PHOTOLYSIS
SOLVOLYSIS
ACETATES
ACETIC ACID
ACETONITRILE
AROMATICS
CHLORINATED ALIPHATIC HYDROCARBONS
COMPARATIVE EVALUATIONS
CYANIDES
DIENES
ELECTRON TRANSFER
EXCITATION
EXPERIMENTAL DATA
FREE ENERGY
KETONES
NITRO COMPOUNDS
NMR SPECTRA
PHOTOCHEMICAL REACTIONS
SILVER COMPOUNDS
STEREOCHEMISTRY
THERMODYNAMIC ACTIVITY
ALKENES
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
DATA
DECOMPOSITION
ENERGY
ENERGY-LEVEL TRANSITIONS
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
INFORMATION
MONOCARBOXYLIC ACIDS
NITRILES
NUMERICAL DATA
ORGANIC ACIDS
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PHYSICAL PROPERTIES
POLYENES
SPECTRA
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPOUNDS
400500* - Photochemistry