Al-based metal-organic gels for selective fluorescence recognition of hydroxyl nitro aromatic compounds

The novel class of luminescent Al3 +-based metal-organic gels (Al-MOGs) have been developed using 4-[2,2′:6′,2″-terpyridine]-4′-ylbenzoic acid (Hcptpy) and Al3 + through various noncovalent interactions. The as-prepared Al-MOGs have multiple stimuli-responsive properties and selective recognition of hydroxyl nitro aromatic compounds, which can quench the fluorescence of the Al-MOGs, while other nitro aromatic analogues without hydroxyl substitutes cannot. The fluorescence quenching of Al-MOGs is attributed to inner filter effects (IFEs), as well as electron transfer (ET) between Al-MOGs and PA.88