Two Zinc(II) metal-organic frameworks with mixed ligands of 5-amino-tetrazolate and l,2,4,5-benzenetetracarboxylate: Synthesis, structural diversity and photoluminescent properties

The reactions of Zn(NO 3 ) 2 ·6H 2 O with mixed ligands of 5-amino-tetrazole (Hatz) and l,2,4,5-benzenetetracarboxylic acid (H 4 btec) under hydro(solvo)thermal conditions, gave two three-dimensional (3D) porous metal-organic frameworks (MOFs) of {[Zn 3 (atz) 2 (btec)(DMF) 2 ]·DMF·2H 2 O} n ( 1 ) and [Zn 2 (Hprz)(atz)(btec)(H 2 O)] n ( 2 ) in the absence and presence of piperazine (prz), respectively. 1 and 2 were characterized by infrared spectra (IR), elemental analyses (EA) and single-crystal/powder X-ray diffraction. In 1, the adjacent 1D [Zn 3 (btec)] n 2 n + chains are linked together by atz − ligands to form a 3D porous MOF with 1D tetragonal channels filled with coordinated and guest DMF, and lattice water molecules. In 2 , the adjacent 2D [Zn 2 (btec)] n wavelike sheets are pillared through atz − ligands to generate a 3D layered-pillared porous MOF with 1D open channels, which are occupied by coordinated Hprz + cations and coordinated water molecules. Additionally, thermal stabilities and photoluminescent properties of both compounds in the solid-state at room temperature have been investigated and discussed in detail.