Synthesis and characterization of subporphyrins with dendritic carbazole arms

A series of novel dendritic carbazole-functionalized subporphyrins, T(Cz-Gn)SubPs (n = 1-3), have been synthesized from pyridine-tri(pyrrol-1-yl)borane and the corresponding aldehydes. This study has demonstrated that intramolecular energy transfer from the carbazole dendron to the subporphyrin core occurs with a high efficiency which decreases with increasing dendron generation, in accord with the Forster mechanism of energy transfer. In addition, the carbazole dendron can lead to a blueshift of the absorption and emission bands of the subporphyrin core. The light-harvesting abilities of these compounds increase with increasing generation. Meanwhile, these dendritic macromolecules emit intense yellow-green light and may be good candidates for photonic devices.