Syntheses, structures and luminescent properties of decorated lanthanide metal-organic frameworks of (E)-4,4 '-(ethene-1,2-diyl)dibenzoic acids

The functionalized ligand (E)-4,4'-(1,4-bis(methylthio)but-2-ene-2,3-diyl)dibenzoic acid (H2LS) and four metal-organic frameworks, [M-2(L-H)(3)(DMSO)(4)]center dot xDMSO (6 and 7 for M = Tb3+, Eu3+ respectively; L-H = (E)-4,4'-(ethene-1,2-diyl)dibenzoate) and [M-2(L-S)(3)(DMF)(2)(H2O)(2)] (8 and 9 for M = Eu3+, Tb3+) have been synthesized and characterized. All four MOFs adopt the anticipated connectivity, but the fold of interpenetration in each MOF crystal varies as a result of different solvent inclusion and ligand functionality. Compounds 6 and 7 contain a large amount of solvent molecules and tend to lose solvent in air. Compounds 8 and 9 are stable crystals without lattice solvent molecules in the crystals; the coordinating solvent molecules can be reversibly removed and replenished with the skeletons intact. All four MOFs show mainly the ligand-based luminescence, while 8 also displays metal-based luminescence.