TPE[2]arenes: Luminescent macrocyclic arenes with aggregation-induced emission and Al3+ detection

Abstract

Luminescent macrocyclic arenes have attracted interest owing to their unique cyclic geometry and adaptive emission. Herein, a series of fluorescent macrocyclic arenes, denoted as TPE [2]arenes, were easily synthesized by the one-pot condensation of tetraphenylethene (TPE) moiety and paraformaldehyde in the presence of BF3·OEt2 and readily derivatized to yield cyclic arenes with diverse substitution patterns. The macrocyclic arenes shared similar cyclic skeleton with resorcin [4]arene, and existed as two enantiomers with boat conformation confirmed via single crystal analysis. Furthermore, TPE [2]arenes all retained the aggregation-induced emission properties owing to the incorporation of TPE moiety and obvious mechanochromic luminescence behavior due to the relative flexible skeleton. The carboxylic acid substituted analogues, namely TPE [2]arene-COOH, exhibited specific “turn-on” detection of Al3+ ion in aqueous media.