Substituted dibenzo[2,3:5,6]-pyrrolizino[1,7-bc]indolo[1,2,3-lm]carbazoles: a series of new electron donors

The synthesis and spectroscopic properties of a series of new organic electron donors derived from dibenzo[2,3:5,6]pyrrolizino-[1,7-bc]indolo[1,2,3-lm]carbazole are described. These compounds can be considered as planar hybrids of carbazole and p-phenylenediamine and possess high thermal stability. The electron donating properties and one- and two-photon spectroscopic features of methoxy derivatives are very sensitive to the number and positions of the methoxy groups. The X-ray structure of the 2,11-dimethoxy derivatives features slipped π-stacks and short interplanar distance between the molecules in the stacks similar to those found in the unsubstituted derivative.