Photoinduced electron-transfer processes involving substituted stilbene oxides

Journal Article · Sat Jan 01 04:00:00 EST 1977 · J. Org. Chem.; (United States)

OSTI ID:7251178

Das, P K; Muller, A J; Griffin, G W

Electron-transfer interactions of several substituted stilbene oxides (oxiranes) containing cyano and carbomethoxy groups at 2,3-positions with the singlet and triplet states of 1,4-dicyanonaphthalene (DCN) and N,N,N',N'-tetramethylbenzidine (TMB) have been investigated by steady-state fluorescence quenching, pulse radiolysis, and laser flash photolysis. The results are examined in the context of the behaviors of the oxiranes with respect to photosensitized isomerization and degradation under steady-state irradiation (350 nm). Transient spectra concerning radical ions and triplets of DCN and TMB as well as primary photoproducts observed in the photosensitization of some of the oxiranes are presented. Evidence for charge-transfer interaction with oxiranes in acetonitrile is obtained from transient-absorption spectral characterization of the radical anion of DCN and the radical cation of TMB; the efficiency of net electron transfer forming solvated radical ions is very small (0-0.3). No transient phenomena attributable to ylides formed via back electron transfer within an ion pair or between solvated radical ions are observed. With trans and cis forms of 2,3-dicarbomethoxy-2,3-bis(4-methoxyphenyl)oxirane, long-lived radical cations with dual absorption maxima at 400 and 580 nm are formed as a result of photosensitization by DCN in acetonitrile. The radical cation from the cis oxirane displays a relatively slow growth (t/sub 1/2/ = 350 ns) for its formation from a charge-transfer-derived precursor with a single absorption maximum at 460 nm; this transient behavior appears to be associated with either relatively slow ring opening of an initially formed, closed ring, radical cation of the cis oxirane via intramolecular electron transfer, or isomerization of an initially formed, open ring, strained configuration to a stable one derivable by electron transfer from the trans oxirane. 33 references, 6 figures, 2 tables.

• Research Organization: Univ. of Notre Dame, IN
• OSTI ID: 7251178
• Journal Information: J. Org. Chem.; (United States), Journal Name: J. Org. Chem.; (United States) Vol. 49:11; ISSN JOCEA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400500 -- Photochemistry
400600* -- Radiation Chemistry
BEAMS
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ELECTRON BEAMS
ELECTRON TRANSFER
EPOXIDES
FLUORESCENCE
IRRADIATION
ISOMERIZATION
LASER RADIATION
LEPTON BEAMS
LUMINESCENCE
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PARTICLE BEAMS
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
PULSED IRRADIATION
QUENCHING
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADIOLYSIS