title: Syntheses and crystal structures of fused thiophenes: [7]helicene and double helicene, a D2-symmetric dimer of 3,3'-bis(dithieno[2,3-b:3',2'-d]thiophene).
abstract: The efficient synthesis of (TMS)(2)-[7]helicene (rac-3) and double helicene, a D(2)-symmetric dimer of 3,3'-bis(dithieno[2,3-b:3',2'-d]thiophene) (rac-4) was developed. The crystal structures of 3 and 4 show both strong intermolecular pi-pi interactions and S...S interactions. UV/vis spectra reveal that both 3 and 4 show significant pi-electron delocalization.
authors.affiliation: Key Laboratory for Special Functional Materials of Ministry of Education, Henan University, Kaifeng, 475004, China.
authors.forename: Chunli
authors.initials: C
authors.lastname: Li
authors.forename: Jianwu
authors.initials: J
authors.lastname: Shi
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.forename: Yangguang
authors.initials: Y
authors.lastname: Wang
authors.forename: Yanxiang
authors.initials: Y
authors.lastname: Cheng
authors.forename: Hua
authors.initials: H
authors.lastname: Wang
mesh_terms: D018360:Crystallography, X-Ray; D019281:Dimerization; D008958:Models, Molecular; D015394:Molecular Structure; D011083:Polycyclic Compounds / Q000138:chemical synthesis* / Q000737:chemistry*; D013237:Stereoisomerism; D013876:Thiophenes / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: C534895:3,3'-bis(dithieno(2,3-b-3',2'-d)thiophene); D011083:Polycyclic Compounds; D013876:Thiophenes; C031660:helicenes