Synthesis and characterization of a novel inorganic–organic hybrid open-framework zinc phosphate with 16-ring channels

•An inorganic–organic hybrid zinc phosphate was synthesized.•Monoprotonated APIM serves as both ligand and countercation in 1.•Intersecting 8-, 10- and 16-ring channels were observed in 1.•Blue ligand-to-metal charge transfer photoluminescence was observed.

A novel inorganic–organic hybrid open-framework zinc phosphate, (NH4)[Zn5(PO4)3(HPO4)2(HAPIM)2]·(H2O) (1), was solvothermally synthesized in the presence of 1-(3-aminopropyl)imidazole (APIM) as structure-directing agent. Its structure is built up by the alternate linkages between ZnO4, ZnO3N, PO4 and HPO4 tetrahedral moieties, forming an unusual three-dimensional framework with intersecting 8-, 10-, and 16-ring channels. The arrangement of the monoprotonated APIM molecules in 1 is unique and they play dual roles as both ligands and countercations. It is the first example with APIM as template in extra-large-channel structures in zincophosphates. The framework contains a Zn/P ratio of 1:1 and exhibits remarkable low framework density. Photoluminescence studies show that there is a ligand-to-metal charge transfer.

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