Luminophore from forgotten dye: di(Alkylthiophene) derivative of benzo[h] benz[5,6]acridino[2,1,9,8-klmna]acridine

A new, solution processable and highly luminescent compound (photoluminescence QY ca. 60%), namely di (alkylthienyl) substituted benzo[h]benz[5,6]acridino[2,1,9,8-klmna] acridine, abbreviated as (FTC-8) was synthesized. FTC-8 is electrochemically active showing a quasi-reversible redox couple at negative potentials (vs Fe/Fe) and an irreversible oxidation peak at positive ones. Its ionization potential and electron affinity values, determined from the cyclic voltammetry results are: IP = 5.48 eV and vertical bar EA vertical bar = 3.36 eV. The effect of the conjugation extension from the azaacene core to alkylthienyl substituent on the electrochemical and spectroscopic properties of FTC-8 is rather weak, which is consistent with DFT calculation showing that the core and the thienyl substituent are almost orthogonal. Taking into account the measured redox properties and efficient luminescence, FTC-8 can be considered as a promising candidate for the fabrication of light emitting diodes. FTC-8 shows also strong tendency to self-assemble forming highly ordered monolayers on HOPG graphite as demonstrated by STM investigations.