Well-defined and monodisperse linear and star-shaped quaterfluorene-DPP molecules: the significance of conjugation and dimensionality.

The synthesis of three new 1,4-diketo-3,6-diphenyl-pyrrolo[3,4-c]pyrrole (DPP) macromolecules appended with two or four quaterfluorene arms is reported. The compounds absorb mainly through the oligofluorene units and emit through the DPP core. Optical gain has been observed for Linear-c, a two-armed structure in which the quaterfluorene units are conjugated through the core unit.