Photoluminescence Properties of Lanthanide‐Organic Frameworks ( Ln OFs) with Thiophene‐2,5‐Dicarboxylate and Acetate

S‐heterocyclic dicarboxylic acid, thiophene‐2,5‐dicarboxylic acid (H 2 TDC), was employed to construct a series of lanthanide‐organic frameworks ( Ln OFs) with coligand acetate, formulated as [ Ln (TDC)(OAc)(H 2 O)] n [ Ln = Eu ( 1 ), Tb ( 2 ), Gd ( 3 ), Dy ( 4 ), Sm ( 5 )] under hydrothermal conditions. Structure analysis reveals that 1 – 5 have dinuclear 3D metal organic frameworks (MOFs), in which TDC 2– and OAc – display (κ 1 ‐κ 1 )‐(κ 1 –κ 1 )‐μ 4 and (κ 2 ‐κ 1 )‐μ 2 coordination fashions, respectively. The dehydrated products of all compounds show high thermal stability above 410 °C. As for 1 , 2 , 4 , and 5 , the photoluminescence analyses exhibit characteristic luminescence emission bands of the corresponding lanthanide ions in the visible region. In particular, compound 2 displays bright green luminescence in the solid state with 5 D 4 lifetime of 0.510 ms and relative high overall quantum yield of 16 %, based on an ideal energy gap between the lowest triplet state energy level of H 2 TDC ligand and the 5 D 4 state energy level of Tb 3+ . The energy transfer mechanisms in compounds 1 and 2 were also discussed.