title: Benzothiophene or benzofuran bridges in diaryl ethenes: two-step access by pd-catalyzed C-H activation and theoretical/experimental studies on their photoreactivity.
abstract: A series of terarylenes incorporating benzothiophene (BT)/benzofuran (BF) as the central ethene unit was synthesised by using sequential Pd-catalysed C-H activation reactions. This new methodology allows the easy modification of the nature of the pendant heteroarene groups. Diaryl ethene (DAE) derivatives with thiophene, thiazole, pyrrole, isoxazole and pyrazole rings were prepared. A large number of asymmetrical DAEs are easily accessible by this new method in both the BT and BF series. The study of their photochromic properties in solution revealed that the nature of the heteroarene and of the central unit drastically modify their photochromic behaviour. TD-DFT calculations were performed to assess the nature of the relevant excited states.
authors.affiliation: Institut des Sciences Chimiques de Rennes, UMR 6226, CNRS-Université de Rennes 1, "Organométalliques, Matériaux et Catalyse", Campus de Beaulieu, 35042 Rennes (France), Fax: (+33) 0223236939.
authors.forename: Kedong
authors.initials: K
authors.lastname: Yuan
authors.forename: Julien
authors.initials: J
authors.lastname: Boixel
authors.forename: Agisilaos
authors.initials: A
authors.lastname: Chantzis
authors.forename: Denis
authors.initials: D
authors.lastname: Jacquemin
authors.forename: Véronique
authors.initials: V
authors.lastname: Guerchais
authors.forename: Henri
authors.initials: H
authors.lastname: Doucet
keywords: CH activation; heterocycles; homogeneous catalysis; palladium; photochromism