Lanthanide(III) based metal organic frameworks constructed from 5-nitroisophthalate ligand with 2,4,5-tri(4-pyridyl)-imidazole templates: Syntheses, structures, and luminescent properties

Two unprecedented Ln-based metal–organic frameworks (MOFs) based on 5-nitroisophthalic acid (H2L) and 2,4,5-tri(4-pyridyl)-imidazole (Htpim), namely {[H3tpim][Ln2(L)4(H2O)]}n [Ln = La (I), Nd (II)], were prepared by solvothermal reactions and characterized by IR, elemental analysis and X-ray diffraction analysis. X-ray single crystal diffraction indicates that complexes I and II display similar 2D 44 frameworks with similar tetranuclear [Ln4(COO)16(H2O)2] secondary building units due to the effect of Ln contraction and the same coordination modes of L ligands as well as the template effect of Htpim. Moreover, thermal stabilities and luminescent properties of I and II were also investigated.

Two Ln-based MOFs have been successfully constructed by 5-nitroisophthalic acid (H2L) and 2,4,5-tri(4-pyridyl)-imidazole (Htpim) and structurally characterized by IR, elemental analysis and X-ray diffraction analysis. Complexes I and II display similar 2D 44 frameworks with similar tetranuclear [Ln4(COO)16(H2O)2] SBUs due to the effect of Ln contraction and the same coordination modes of L ligands as well as the template effect of Htpim. Moreover, thermal stabilities and luminescent properties of I and II were also investigated. They are stable up to 177 °C and 190 °C, respectively. Their emissions mainly originate from ligand-based luminescence, corresponding shifts originated from LMCT.Figure optionsDownload as PowerPoint slide