Synthesis of a helical boron-doped PAH by post-functionalization of 3,9-diboraperylene

Abstract

We present herein the post-functionalization of doubly boron-doped polycyclic aromatic hydrocarbons (PAHs) by various aryl substituents, namely the syntheses of a series of (2,8,)3,9-aryl-substituted 3,9-diboraperylenes via boron-substitution of (2,8-diaryl-)3,9-dihydroxy-3,9-diboraperylenes. These new boron-doped PAHs exhibit two reversible reductions with a remarkably facile first reduction between E = −1.04 and −1.13 V vs. Fc⁺/Fc. Friedel–Crafts cyclization of the 2-isopropenylnaphthyl-substituted derivative afforded a helical boron-doped polycyclic aromatic hydrocarbon that is endowed with a low LUMO level, high absorption coefficients and fluorescence (Φ_F = 0.73), combined with a one-dimensional π–π stacking interaction in the solid state.