Corroles bearing diverse coumarin units — synthesis and optical properties

Two strategies were shown to be efficient in the construction of corroles with appended coumarin units. Direct condensation of formyl-coumarins with dipyrromethanes leads to a diverse range of trans-A 2 B-corroles in moderate yields. We showed that the strategy consisting of synthesis of various hydroxycoumarins followed by nucleophilic aromatic substitution with pentafluorobenzaldehyde and subsequent condensation of the resulting coumarin-aldehyde with dipyrromethanes is the most general methodology for the preparation of such dyads. The second, more demanding but also more efficient approach is based on Sonogashira coupling of ethynylphenylcorroles with suitably functionalized bromocoumarins. A broad range of structurally diverse coumarins were employed with absorption ranging from 300 to 460 nm. Spectroscopic properties of all eight dyads studied suggest that the linker components are weakly electronically coupled.