title: Planar beta-linked oligothiophenes based on thieno[3,2-b]thiophene and dithieno[3,2-b:2',3'-d]thiophene fused units.
abstract: A series of planar beta-linked oligothiophenes based on thieno[3,2-b]thiophene and dithieno[3,2-b:2',3'-d]thiophene fused units were synthesized. The optical data indicate a blue shift of the absorption maximum in comparison to the alpha-linked analogues due to cross-conjugation between fused rings. The crystal structures of 3,3'-bi(thieno[3,2-b]thiophene) and 3,3';6',3"-ter(thieno-[3,2-b]thiophene) reveal edge-to-face pi-stacked dimer motifs, whereas the crystal structure of 3,3'-bis(dithieno[3,2-b:2',3'-d]thiophene) consists of face-to-face pi-stacked molecules. [structure: see text]
authors.affiliation: Department of Chemistry and the Macromolecular Science and Engineering Program, University of Michigan, 930 North University, Ann Arbor, MI 48109-1055, USA.
authors.forename: Lidaris
authors.initials: L
authors.lastname: San Miguel
authors.forename: William W
authors.initials: WW
authors.lastname: Porter
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Matzger