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Push-pull chromophores by reaction of 2,3,5,6-tetrahalo-1,4-benzoquinones with 4-(N,N-dialkylanilino)acetylenes

2016-03-03
Dengiz, Çağatay
PRANGE, Celine
GAWEL, Przemyslaw
TRAPP, Nils
RUHLMANN, Laurent
BOUDON, Corinne
DIEDERICH, Francois
A series of new push-pull chromophores were synthesized from electron-rich 4-(N,N-dialkylanilino) acetylenes and 2,3,5,6-tetrahalo-1,4-benzoquinones. The reactivity of the latter differs substantially from that of the previously investigated 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The transformation with fluoranil gave orange-colored, bis-donor-substituted chromophores with a tricyclic, cyclobutene-fused dihydrobenzofuranone core. In contrast, the reaction with chioranil yielded mono donor-substituted, blue 1,4-benzoquinone-based chromophores, which were further reacted with tertiary amines to form bis-donor-substituted push-pull systems. The structures of the new chromophores were confirmed by X-ray analysis, and mechanisms for their formation are proposed. They feature intense intramolecular charge-transfer bands in the visible region, and their optoelectronic properties were investigated by UV/Vis spectroscopy, electrochemistry, and computational analysis. (C) 2016 Elsevier Ltd. All rights reserved.