Laser flash photolysis study of (2-anthryl)ethylenes. Triplet-related photophysical behaviors
The triplet-state photophysical behaviors of three trans-1,2-diarylethylenes with a phenyl, 2-naphtyl, or 2-thienyl group as one substituent and a 2-anthryl as the other have been studied by laser flash photolysis and pulse radiolysis. The triplets have been generated by energy transfer under sensitized conditions, direct intersystem crossing (in bromobenzene), and assisted intersystem crossing in the presence of such singlet quenchers as oxygen, ethyl iodide (EtI), di-tert-butyl nitroxide (DTBN), and N,N-dimethylaniline (DMA). The absorption spectra of the triplets are sharp, intense, and well resolved and display two major band systems at 400-500 and 550-650 nm, respectively. The observed triplet lifetimes (tau/sub T/) are in the range 15-120 ..mu..s. On the basis of the data concerning triplet-triplet (T-T) spectra, tau/sub T/'s, triplet quenching by azulene and di-tert-butyl nitroxide, and Stern-Volmer behavior for triplet formation via exciplexes with N,N-dimethylaniline, the triplets are assignable to predominantly one conformeric species, or multiple species with indistinguishable spectral and kinetic behaviors, with the excitation energy in either case being localized primarily on the anthracene moiety. In the case of 1-(2-thienyl)-2-(2-anthryl)ethylene, triplet-related formation and decay processes with associated lifetimes 100-120 ns are observed at the initial stage following the laser excitation; these are tentatively attributed to intramolecular relaxation in the initially formed triplet conformers in the form of rotation of aryl groups about quasi-single bonds. 5 figures, 3 tables.
- Research Organization:
- Univ. of Notre Dame, IN
- OSTI ID:
- 6550020
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 88:6
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ALKENES
EXCITATION
STRUCTURAL CHEMICAL ANALYSIS
ABSORPTION SPECTRA
AMINES
BENZENE
CONDENSED AROMATICS
EXPERIMENTAL DATA
IODINATED ALIPHATIC HYDROCARBONS
LASER RADIATION
NITROGEN OXIDES
ORGANIC SOLVENTS
OXYGEN
PHOTOLYSIS
REACTION INTERMEDIATES
TIME DEPENDENCE
VIBRATIONAL STATES
AROMATICS
CHALCOGENIDES
CHEMICAL REACTIONS
DATA
DECOMPOSITION
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
HALOGENATED ALIPHATIC HYDROCARBONS
HYDROCARBONS
INFORMATION
NITROGEN COMPOUNDS
NONMETALS
NUMERICAL DATA
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PHOTOCHEMICAL REACTIONS
RADIATIONS
SOLVENTS
SPECTRA
400301* - Organic Chemistry- Chemical & Physicochemical Properties- (-1987)
400500 - Photochemistry