Substitution effects on the properties of 10,13-disubstituted dipyrido[3,2-a:2′,3′-c]phenazine donor–acceptor compounds and their ruthenium(II) complexes

A series of T-shaped donor–acceptor (D–A) dipyrido[3,2-a:2′,3′-c]phenazine (dppz) and benzothiadiazole based molecules, extended by different electron-donating chromophores at 10 and 13 positions (4-dibenzothiophene, isomeric 4-(9H-carbozol-9-yl)phenyl and 9-phenyl-9H-carbazol-3-yl), has been designed and prepared successfully in order to explore the impacts of substituents on the molecular structures and properties. It is worth mentioning that three pairs of structural isomers (3 and 4, 7 and 8, 11 and 12) are obtained, where distinguishable UV–vis and fluorescence spectra, thermal stability and band gaps have been observed. In particular, dibenzothiophene/benzothiadiazole based compound 2 displays the best luminescence emission, and 9-phenyl-9H-carbazole/dppz derivative 8 exhibits excellent thermal stability with the Td10 value as high as 519 °C. Furthermore, four ruthenium(II) complexes [Ru(bpy)2L]Cl2 (bpy=2,2′-bipyridine and L=dppz based derivatives 5–8) have been synthesized for comparisons.

A series of T-shaped donor–acceptor dipyrido[3,2-a:2′,3′-c]phenazine and benzothiadiazole based compounds, extended by different chromophores at 10 and 13 positions, has been described, together with corresponding ruthenium(II) complexes.Figure optionsDownload as PowerPoint slide