title: Stacking patterns of thieno[3,2-b]thiophenes functionalized by sequential palladium-catalyzed Suzuki and Heck cross-coupling reactions.
abstract: The crystal structures of three 5-alkenyl-2-arylthieno[3,2-b]thiophenes, namely 3,6-dibromo-5-(4-tert-butylstyryl)-2-(naphthalen-1-yl)thieno[3,2-b]thiophene, C(28)H(22)Br(2)S(2), (I), 3,6-dibromo-5-(4-methylstyryl)-2-(naphthalen-1-yl)thieno[3,2-b]thiophene, C(25)H(16)Br(2)S(2), (II), and 3,6-dibromo-2-(4-tert-butylphenyl)-5-(4-methylstyryl)thieno[3,2-b]thiophene, C(25)H(22)Br(2)S(2), (III), have been determined in order to evaluate the geometry of the molecules. The π-conjugated system containing the thieno[3,2-b]thiophene skeleton, the ethylene bridge and the phenyl rings is almost planar. The aromatic ring directly attached to the thieno[3,2-b]thiophene moiety is not coplanar with the thieno[3,2-b]thiophene moiety itself due to steric hindrance of the bromo substituent. The crystal packings are characterized by π-π stacking [only for (II)] and C-Br...π interactions. The long axes of the molecules in (I) are oriented in two directions; for the two other structures the long axis is oriented in one direction only.
authors.affiliation: Chemistry Department, Hanoi National University of Education, 136-Xuan Thuy-Cau Giay, Hanoi, Vietnam.
authors.forename: Hien
authors.initials: H
authors.lastname: Nguyen
authors.affiliation: Chemistry Department, Hanoi National University of Education, 136-Xuan Thuy-Cau Giay, Hanoi, Vietnam.
authors.forename: Ngan
authors.initials: N
authors.lastname: Nguyen Bich
authors.affiliation: Centre d'Élaboration de Matériaux et d'Études Structurales, 29 rue Jeanne Marvig BP 94347, 31055 Toulouse Cedex 4, France.
authors.forename: Tung T
authors.initials: TT
authors.lastname: Dang
authors.affiliation: Chemistry Department, KU Leuven, Celestijnenlaan 200F, B-3001 Leuven (Heverlee), Belgium.
authors.forename: Luc
authors.initials: L
authors.lastname: Van Meervelt
keywords: D-π-A organic dyes; Heck cross-coupling reactions; NMR analysis; Suzuki reactions; crystal structure; dye-sensitized solar cells; thieno[3,2-b]thiophene; π-conjugated systems