Angewandte Chemie International Edition
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Inside Cover: Preferential Formation of Cyclic Trimers by Palladium-Catalyzed Oxidative Coupling Reactions of 2,18-Diethynylporphyrins (Angew. Chem. Int. Ed. 49/2012)
Cyclic porphyrin oligomers are difficult to obtain efficiently. In their Communication on page 12357 ff., A. Osuka, H. Yorimitsu, and S. Tokuji show Pd-catalyzed trimerization of 2,18-diethynylporphyrins. Hexaporphyrins with meso–meso directly linked porphyrins can be used to model a light-harvesting antenna. The crystal structure of the trimer resembles the family crest of Mitsuba-aoi (three leaves of Hollyhock), which is the famous crest of the Tokugawa clan.