Dioxin-annulated 1,8-naphthalimides – Synthesis, spectral and electrochemical properties, and application in OLED

Abstract A synthetic approach for preparation of a new class of 1,8-naphthalimide derivatives with fused benzo and naphtho-dioxin systems is reported. The proposed reaction conditions for the first step allow selective bromination of 1,8-naphthalic anhydride to the corresponding 3,4,6-tribromo derivative, which has the potential to be versatile building block in the chemistry of naphthalimides. The dioxin-annulated products were isolated in very good yields and their applicability for further modifications by metal-catalysed coupling reactions was proven. The synthesized fluorescent dyes showed media dependant emission and their photophysical and electroluminescent properties were evaluated with respect to their application in OLED. TGA measurements showed that all compounds are stable up to above 400 °C The best OLED test device has turn-on voltage of 8 V; maximum luminescent intensity of 3031 cd/m2, and current efficiency of 6.9 cd/A.