Synthesis, crystal structures, and photophysical properties of a series of novel tetrahydrobenzodiacridines

Several novel 6,7,14,15-tetrahydro-benzo[1,2-c:4,5-c′]diacridine derivatives (1a-1h) were synthesized in this study. Compounds 1a-1h were thermally robust with high decomposition temperatures (≥359.5 °C) and high melting points (223.7 °C-452.2 °C). On the other hand, compound 1b was crystallized in a triclinic system, containing space groups P-1. Compounds 1a-1h showed UV-vis absorption (λ_max^Abs) in the range of 372 nm-377 nm in chloroform solutions and 381 nm-389 nm in solid states. They also showed fluorescence (λ_max^Em) in the range of 374 nm-389 nm in chloroform solutions and 421 nm-457 nm in solid states. Moreover, these compounds exhibited good fluorescence quantum yields ranging from 43.5% to 96.1%. Compounds 1a-1h showed a formal reduction potential in the range of -1.95 V to -2.13 V (vs. SCE), and their LUMO and HOMO levels were 2.27 eV-2.45 eV and 4.92 eV-6.31 eV, respectively. These results demonstrate that novel 6,7,14,15-tetrahydro-benzo[1,2-c:4,5-c′]diacridine derivatives (1a-1h) are promising thermally stable blue light-emitting materials with good electron transport and good hole-blocking properties for organic light-emitting diodes.