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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Photoinduced Charge Shifts and Electron Transfer in Viologen-Tetraphenylborate Complexes: Push-Pull Character of the Exciplex

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Santos, Willy G. ; Budkina, Darya S. ; Deflon, Victor M. ; Tarnovsky, Alexander N. ; Cardoso, Daniel R. ; Forbes, Malcolm D. E.
Total Authors: 6
Document type: Journal article
Source: Journal of the American Chemical Society; v. 139, n. 23, p. 7681-7684, JUN 14 2017.
Web of Science Citations: 16

Viologen tetraarylborate ion-pair complexes were prepared and investigated by steady-state and time-resolved spectroscopic techniques such as fluorescence and femtosecond transient absorption. The results highlight a charge transfer transition that leads to changes in the viologen structure in the excited singlet state. Femtosecond transient absorption reveals the formation of excited-state absorption and stimulated emission bands assigned to the planar (k(obs) < 10(12) s(-1)) and twisted (k(obs) 10(10) s(-1)) structures between two pyridinium groups in the viologen ion. An efficient photoinduced electron transfer from the tetraphenylborate anionic moiety to the viologen dication was observed less than 1 mu s after excitation. This is a consequence of the push pull character of the electron donor twisted viologen structure, which helps formation of the borate triplet state. The borate triplet state is deactivated further via a second electron transfer process, generating viologen cation radical (V center dot+). (AU)

FAPESP's process: 15/13756-1 - Photochemistry and Excited-states dynamics of Tetraarylborates and Tetraarylborate-pyridinium complexes
Grantee:Willy Glen Santos
Support type: Scholarships abroad - Research Internship - Post-doctor
FAPESP's process: 12/19823-4 - Phototransients of organoboranes generated by photolysis and flavin sensitization
Grantee:Willy Glen Santos
Support type: Scholarships in Brazil - Post-Doctorate