Synthesis and properties of novel perylenetetracarboxylic diimide derivatives fused with BODIPY units

Two novel fluorescent dyes based on perylenetetracarboxylic diimde (PDI) with methylpyridine or methylquinoline group at the carbonyl position were designed and synthesized. Their structures were confirmed by 1H NMR, 13C NMR, MS, and elementary analysis. The resulted new compounds show longer wavelength absorption with relative high extinction coefficient and red-shifted emission with high fluorescence quantum yields. These compounds can further react with BF3·Et2O to form novel dyes containing BODIPY (difluoroboradiazaindacene) analogue unit, by which both the absorption and emission maximum have been red-shifted further. The minimized structures based on density function theory (DFT) calculation show planar configurations for the compounds. The calculated molecular orbital correlates well with their red-shifted absorption and emission spectra.