Carboxyphenyl-terpyridine-based series of gels for procedural visual recognition of multi-anions

The gelation of 4-[2,2′:6′,2′′-terpyridine]-4′-ylbenzoic acid (Hcptpy) occurred with various metal ions and specific anions. With the gel formation, corresponding metal ions and anions were recognized. Also, the metal–organic gels (MOGs) possess stimuli response property to anions. A step-by-step anion recognition progress was established based on one Hcptpy ligand and realized the selective identification 12 kinds of anions.