A facile approach toward 1,2-diazabenzo[ghi]perylene derivatives: structures and electronic properties

A new class of pyridazine fused aromatics, 1,2-diazabenzo[ghi]perylenes, is conveniently synthesized from 2,7-dihydroxynaphthalene via intermolecular oxidative coupling followed by a condensation reaction. These new compounds are fully characterized via X-ray crystallographic analysis, optical spectroscopy and electrochemistry, in addition to DFT calculations. They show a twisted structure and unique P-/P- and M-/M-enantiomer pairs are observed in their single crystals. They exhibit intramolecular charge transfer character and emit at a longer wavelength with a larger Stokes shift compared with their all-carbon analog.