Waghray, D. and Cloet, A. and Van Hecke, K. and Mertens, S.F.L. and De Feyter, S. and Van Meervelt, L. and Van Der Auweraer, M. and Dehaen, W. (2013) Diazadithia[7]helicenes: Synthetic exploration, solid-state structure, and properties. Chemistry - A European Journal, 19 (36). pp. 12077-12085. ISSN 0947-6539
Full text not available from this repository.Abstract
Diazadithia[7]helicenes were synthesized from the readily available building block ethyl 7-chloro-8-formylthieno[3,2-f]quinoline-2-carboxylate by a Wittig reaction-photocyclization strategy. The helicene core was functionalized by nucleophilic aromatic substitution with a variety of nucleophiles (e.g., O-, N-, and C-centered) and palladium-catalyzed reactions such as Suzuki coupling and Buchwald-Hartwig amination. Racemization studies confirmed that the enantiopure forms of these [7]helicenes are conformationally stable compared to their lower analogues. The solid-state structures of the novel diazadithia[7]helicenes were determined by single-crystal X-ray diffraction. The crystal structures of these azathia[7]helicenes show columnar stacking in antiparallel fashion. The HOMO-LUMO gaps of the new compounds were determined on the basis of electrochemical and optical measurements.