Synthesis of a novel aminobenzene-containing hemicucurbituril and its fluorescence spectral properties with ions

A novel hemicucurbituril-based macrocycle, alternately consisting of amidobenzene and 2-imidazolidione moieties was designed and synthesized. Based on the fragment coupling strategy, nitrobenzene-containing hemicucurbituril was firstly prepared facilely under alkaline environment, and reduction of the nitro groups produced the desired amidobenzene-containing hemicucurbituril. As an original fluorescent chemosensor, it exhibited strong interactions with Fe(3+) over other metal cations. The experimental evidence of fluorescence spectra suggested that a 1:1 complex was formed between this macrocycle and Fe(3+) with an association constant up to (2.1 ± 0.3) × 10(4) M(−1). Meanwhile, this macrocycle showed no obvious or only slight enhancement of the fluorescence intensity with selected anions.