Angewandte Chemie International Edition
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Back Cover: Indeno[2,1-b]fluorene: A 20-π-Electron Hydrocarbon with Very Low-Energy Light Absorption (Angew. Chem. Int. Ed. 23/2013)
10,12-dimesitylindeno[2,1-b]fluorene ... ... exhibits a very-low-energy light-absorption band that extends to 2000 nm, despite its small conjugation space of only 20 π electrons. This first example of a meta-quinodimethane embedded in an indenofluorene framework is presented by Y. Tobe and co-workers in their Communication on page 6076 ff. The unusual absorption behavior is attributed to the moderate singlet biradical character and the small π-conjugation space of the hydrocarbon.