Two new MOFs (Th/ Ce -TCPE) based on 1,2,4,5-tetrakis(4-carboxyphenyl)ethylene (H4TCPE) were obtained using a straightforward reaction under moderate conditions. Th and Ce formed the central units of this MOF in the mononuclear and in the unusual trinuclear cluster configurations, respectively. The resulting MOFs were analyzed by fluorescence spectroscopy to understand their luminescence. The obtained data revealed that benzene's electron cloud density and torsion angle on the ligand were affected by the acetic acid molecule and Th(IV), which caused Th-TCPE to irradiate stronger blue emission, but Ce-TCPE showed no fluorescence due to the self-quenching. Such unique luminescence property could be used for fluorescence or radiopharmaceutical sensing.

Compound 1 (Th-TCPE): 11.40 mg of Th(NO₃)₄·5H₂O, 10.17 mg of H4TCPE and 0.40 mL glacial acetic acid were mixed with 1.5 ml of DMF in a 7 ml vial, which was then sealed and heated to 80 ℃ for 48 h. The absinthe-green crystalline powder was filtered to separate it from the mother solution, washed three times with 30 ml of DMF, three times with 30 ml of EtOH, and dried at room temperature. The amounts of these reagents were reduced ten times to synthesize single crystals using the same procedure. The yield was 65.2% recalculated relative to the initial H4TCPE amount. The elemental analysis confirmed that the formula of the synthesized compounds could be expressed as Th₄(TCPE)₂(C₂H₃O₂)₈(C₃H₇NO)₃(H₂O)₂₀. The molecular weight is 2409.36. The theoretical C, H, and N weight contents in this compound (equal to 33.89%, 3.73%, and 1.53%, respectively) corresponded well to those obtained from the experimental analyses (equal to 34.12%, 3.45%, and 1.66%, respectively).

Compound 2 (Ce-TCPE): 10.25 mg of Ce(NO₃)₄, 10.17 mg of H4TCPE, 0.05 mL of glacial acetic and 1.5 ml of DMF were sealed in a 7 ml contained and heated at 100 ℃ for 12 h. The resulting powder was filtered, washed three times with 30 ml of DMF, then three times with 30 ml of EtOH, and dried at room temperature. The amounts of these reagents were reduced ten times to synthesize single crystals using the same procedure. The final product yield was 62.2%, calculated relative to the initial H4TCPE amount. The theoretical C, H and N weight contents calculated for the resulting Ce(IV)Ce(III)₂(μ-OH)₂(TCPE)₂(C₃H₇NO)₄(H₂O)₅ (The molecular weight is 1461.22) compound should be equal to 46.86%, 3.80%, and 3.04%, respectively. Corresponding C, H and N contents determined analytically were equal to 46.69%, 3.67%, and 2.78%, respectively.