Aggregation-enhanced emission and through-space conjugation of tetraarylethanes and folded tetraarylethenes

Aggregation-induced emission luminogens (AlEgens) are attracting rapidly increasing interest, due to their promising applications in various research frontiers. Tetraarylethenes are the most extensively studied AlEgens, which are usually prepared by McMurry couplings. In this study, we prepare not only new folded tetraarylethenes, but also tetraarylethanes by the McMurry coupling of different diarylmethanones. Moreover, the crystal structures, photophysical properties, orbital distributions, thermal stabilities and electrochemical behaviors of tetraarylethanes and folded tetraarylethenes are investigated. The new luminogens show through-space conjugation and aggregation-enhanced emission with high solid-state emission efficiencies approaching unity. Non-doped OLEDs based on the folded tetraarylethenes are fabricated, which perform well, affording high luminance up to 49 030 cd m(-2) and good electro-luminescence efficiencies of 6.6 cd A(-1) and 2.5%.