Photoassociation and photoinduced charge transfer in bridged diaryl compounds. 6. Intramolecular triplet excimers of dicarbazolylalkanes and their comparison to an intermolecular triplet excimer of carbazole

Journal Article · Thu Mar 10 00:00:00 EST 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100061a004· OSTI ID:7267382

Cai, J; Lim, E C ^[1]

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1. Univ. of Akron, OH (United States)

A time-resolved emission study of intramolecular triplet excimer formation has been carried out for dicarbazolylmethane (DCM) and dicarbazolylpropane (DCP) in fluid solution at room temperature. The triplet excimer formation was deduced from the comparison of the phosphorescence with the corresponding emission from the intermolecular triplet excimer of carbazole. It has been found that whereas the triplet excimer formation in DCP is evident in both polar and nonpolar solvents, the excimer formation in DCM is observed only in polar solvents at longer delay times. The result indicates that the conformation favored by the triplet excimer is more readily attainable in DCP than in DCM. The enhancement of the triplet excimer formation by polar solvent, which is also observed for carbazole, suggests that the triplet excimers are stabilized (at least in part) by charge resonance interactions. Comparison of the temporal characteristics of the normal delayed fluorescence of DCP with those of the corresponding excimer phosphorescence suggests that the delayed fluorescence at long delay times is produced by bimolecular annihilation of the intramolecular triplet excimers. This in turn implies that the excited singlet-state species produced by bimolecular annihilation of the triplet excimers is unstable and rearranges into monomeric (i.e., non-interacting) conformation prior to its decay by emission of radiation. 16 refs., 7 figs.

• DOE Contract Number: FG02-89ER14024
• OSTI ID: 7267382
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 98:10; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AROMATICS
EXCITED STATES
PHOTOCHEMICAL REACTIONS
CARBAZOLES
EXCIMER LASERS
FLUORESCENCE
PHOSPHORESCENCE
SOLUTIONS
TRIPLETS
AZAARENES
AZOLES
CHEMICAL REACTIONS
DISPERSIONS
ENERGY LEVELS
GAS LASERS
HETEROCYCLIC COMPOUNDS
LASERS
LUMINESCENCE
MIXTURES
MULTIPLETS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
400201* - Chemical & Physicochemical Properties
400500 - Photochemistry