A Dual-Functional Luminescent MOF Sensor for Phenylmethanol Molecule and Tb3+ Cation

A highly luminescent porous metal-organic framework Cd-3(L)(2.5)(4-PTZ)(DMF)(3), labeled as NBU-9, has been designedly synthesized based on Cd(NO3)(2)4H(2)O and mixed ligands of 4-(1H-tetrazol-5-yl)pyridine (4-HPTZ) with N-coordinated sites and thiophene-2,5-dicarboxylic acid (H2L) with heteroatomic (S) ring and carboxylate groups in N,N-dimethylformamide (DMF) at 100 degrees C for 3 days. The interesting result is that this compound NBU-9 can be also obtained via the mixed raw materials of Cd(NO3)(2)4H(2)O, 4-cyanopyridine, NaN3, and H2L under solvothermal condition at a higher temperature of 140 degrees C for 3 days, involving in situ ligand synthesis of 4-HPTZ. Its structure was indentified by single-crystal X-ray study, powder X-ray diffraction, element analysis, and TGA results. Structural analysis shows that the three-dimensional framework of NBU-9 contains cubic channels of 9.59 x 10.26 angstrom(2) covered by a large number of open S- and O-coordinated sites and can be simplified into a 8-connected uninodal eca net with high potential solvent accessible volumes of 34.1%. Its luminescent properties demonstrate that NBU-9 as a multifunctional sensory material realizes the selective detection for the phenylmethanol molecule on the basis of fluorescence quenching mechanism and effectively sensitizing the visible emitting of the Tb3+ cation based on luminescence enhancement.