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Bipolar Molecules with High Triplet Energies: Synthesis, Photophysical, and Structural Properties.

Zheng, Y.; Batsanov, A.S.; Jankus, V.; Dias, F.B.; Bryce, M.R.; Monkman, A.P.


Y. Zheng

V. Jankus

M.R. Bryce


This article sheds new light on the interplay of electronic and conformational effects in luminescent bipolar molecules. A series of carbazole/1,3,4-oxadiazole hybrid molecules is described in which the optoelectronic properties are systematically varied by substituent effects which tune the intramolecular torsion angles. The synthesis, photophysical properties, cyclic voltammetric data, X-ray crystal structures, and DFT calculations are presented. Excited state intramolecular charge transfer (ICT) is observed from the donor carbazole/2,7-dimethoxycarbazole to the acceptor phenyl/diphenyloxadiazole moieties. Introducing more bulky substituents onto the diphenyloxadiazole fragment systematically increases the singlet and triplet energy levels (ES and ET) and blue shifts the absorption and emission bands. The triplet excited state is located mostly on the oxadiazole unit. The introduction of 2,7-dimethoxy substituents onto the carbazole moiety lowers the value of ES, although ET is unaffected, which means that the singlet–triplet gap is reduced (for 7bES – ET = 0.61 eV). A strategy has been established for achieving unusually high triplet levels for bipolar molecules (ET = 2.64–2.78 eV at 14 K) while at the same time limiting the increase in the singlet energy.


Zheng, Y., Batsanov, A., Jankus, V., Dias, F., Bryce, M., & Monkman, A. (2011). Bipolar Molecules with High Triplet Energies: Synthesis, Photophysical, and Structural Properties. Journal of Organic Chemistry, 76(20), 8300-8310.

Journal Article Type Article
Online Publication Date Sep 27, 2011
Publication Date 2011-10
Deposit Date Jan 30, 2012
Journal Journal of Organic Chemistry
Print ISSN 0022-3263
Electronic ISSN 1520-6904
Publisher American Chemical Society
Peer Reviewed Peer Reviewed
Volume 76
Issue 20
Pages 8300-8310