Three novel zinc(ii) metal–organic frameworks based on three tetrazolate ligands: synthesis, structures and photoluminescence

Abstract

Three metal–organic frameworks (MOFs), namely [Zn(BPT)H₂O] (JUC-121), [Zn₅(IBT)₆]·8[H₂N(CH₃)₂]·DMA (JUC-122) and [Zn(TPD)(H₂O)₂]·0.5H₂O (JUC-123) (JUC = Jilin University, China), H₂BPT = (5-bromo-1,3-phenylene)bis(tetrazole), H₃IBT = 4,5-bis(tetrazol-5-yl)imidazole and H₂TPD = 3,5-di(tetrazol-5-yl)pyridine, were obtained by the reactions of Zn(NO₃)₂·6H₂O and three tetrazolate ligands, which were characterized by single crystal X-ray diffraction, thermal gravimetric analyses (TGA), Fourier-transform infrared spectra (FT-IR), elemental analysis (CHN) and powder X-ray diffraction (PXRD). From the crystal structures of these complexes and the coordination modes of the ligands, we can see that the tetrazolate ligands have multi-connectivity abilities to obtain intriguing varieties of molecular architectures. JUC-121 displays a three-dimensional (3D) network with the point symbol (4·6⁵)₂(4²·8⁴)(6⁴·8²). JUC-122 shows a two-dimensional (2D) framework with the point symbol (24³)₂(24)₉ and JUC-123 has a 2D bimodal (3, 3)-connected net with the point symbol (4·8²). The solid-state fluorescent spectra of JUC-121, JUC-122, JUC-123 and the free ligands were measured at room temperature.