Five
novel lanthanide metal–organic frameworks constructed
from a π-conjugated ligand with tetracarboxylate group, 5,5′-(naphthalene-1,5-diyl)diisophthalic
acid, have been synthesized solvothermally. Depend on the single-crystal
X-ray diffraction data, the series of compounds exhibit 3D microporous
framework architectures with two kinds of 1D open channels, giving
the free volume about 36.5% calculated through PLATON. Room-temperature
luminescent behaviors in the solid state reveal that compounds 2 (Eu-MOF) and 4 (Tb-MOF) exhibit the characteristic
emissions of Eu(III) and Tb(III) benefiting from the excellent antenna
effect of the ligand. It is noteworthy that the Eu-MOF, compound 2, has been proven to be treated as a fluorescent switch for
DMF with more than 2-fold enhancement and acetone, which triggers
a superior luminescence quenching giving an almost 100% quenching
efficiency, based on sensitively turned on and turned off effects,
respectively.