Cover Picture: Tetrameric ααββ Aggregate Formation by Stereoisomeric Bidomain Helicene Oligomers (Angew. Chem. Int. Ed. 20/2013)



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Tetrameric aggregates with an ααββ structure are formed by a method using stereoisomeric bidomain oligomers for the α- and β-subunits, as described in the Communication on page 5290 ff. by M. Yamaguchi et al‥ Mixing the dimeric αα and ββ homoaggregates gave tetrameric ααββ heteroaggregates without formation of higher and lower aggregates. The tetrameric aggregate reversibly changed its structure between the dimeric homoaggregates on heating and cooling, and gelation occurred in toluene by polymerization.