Improved structural order, stability, and anion-exchange capacity of cation-mediated bridged hybrid mesoscopic materials by using chelating ligands

Abstract

The anion-exchange property of upgraded metal cation-mediated bridged hybrid mesoscopic material (MBH-S) is greatly improved by replacing initial unidentate ligands with chelating ligands in the framework. Compared to conventional MBH samples, the upgraded MBH-S shows a well-ordered hexagonal mesostructure and a remarkably high anion-exchange capacity. Significantly, the upgraded MBH-S shows a good hydrothermal stability and can keep its anion-exchange capacity unchanged during repeated ion-exchange procedures, which is very important for this type of material to be used in practical application as an anion exchanger. As examples, an anion molecule of tris(8- hydroxyquinoline-5-sulfonate)aluminum (Al(SQ)3) with strong luminescence can be exchanged into MBH-S, forming composite solid of MBH-S-Al(SQ)3 with very strong green luminescence under the excitation of UV light (λexc = 360 nm). A functional molecule of copper phthalocyanine tetrasulfonic acid (CuPcTS) has been employed as a guest to assemble hybrid solid material, MBH-S-CuPcTS.