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 (λmaxAbs) in the range of 372 nm–377 nm in chloroform solutions and 381 nm–389 nm in solid states. They also showed fluorescence (λmaxEm) 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.