Twisted, <i>Z-Shaped</i> Perylene Bisimide

The first derivative of a new class of perylene bisimide chromophores, N,N‘-bis(octyl)-3,9-bis(phenyl)perylene-1,2,7,8-tetracarboxyl bisimide, 1, has been synthesized and its fundamental photophysical and electrochemical properties assessed. The extended, Z-shaped structure was achieved by use of the classic photoenolization of an o-methylbenzophenone analogue, 1,5-dibenzoyl-9,10-dihydroanthracene, and in situ Diels−Alder trapping of the resulting o-xylylenol intermediates with N-octylmaleimide. Subsequent dehydration and aromatization of the resulting bisadduct afforded 1. In dichloromethane, bisimide 1 has an absorption λmax at 491 nm (ε = 29,600 M-1 cm-1), a fluorescence λmax at 517 nm with a high quantum yield (Φ = 0.70), and a single-exponential fluorescence decay (τ = 5.01 ns). Pure crystals of 1 have red emission, suggesting exciplex formation in the solid state. X-ray crystallographic analysis of 1 revealed significant twisting of its perylene core.