Two three-dimensional luminescent coordination polymers, CP1 (C48H36N10O15Zn3) and CP2 (C15H10N4Ni2O7), were synthesized via a solvothermal strategy and characterized by single-crystal X-ray diffraction. CP1 features a three-dimensional Zn(II)-based framework, whereas CP2 contains tetranuclear Ni(II) secondary building units. Both polymers exhibit good thermal stability and excellent structural integrity in aqueous media. Fluorescence sensing experiments demonstrate that CP1 selectively detects Fe & sup3;(+) ions, with a Stern-Volmer quenching constant (Ksv) of 8.74 & times; 104 M-1 and a detection limit (LOD) of 3.20 mu M. In contrast, CP2 shows high selectivity toward CrO4 & sup2;(-) anions, with a Ksv of 1.27 & times; 105 M-1 and an LOD of 1.23 mu M. Mechanistic investigations suggest that fluorescence quenching is primarily associated with competitive absorption of excitation energy through the inner filter effect (IFE), while differences in metal centers and framework architectures may contribute to analyte selectivity. These findings highlight the potential of water-stable coordination polymers for selective fluorescence detection of ionic pollutants in aqueous environments.
Lanthanides complexes are crucial for modern technologies, paving the way for advancing biomedicine, data storage, and environmental remediation. In the present study, the crystal structures of the perchlorate complexes [Ln2(Gly)6 & centerdot;nH2O](ClO4)6 (where Ln = Sm, Eu, Gd, Dy, and n = 9, 9, 9, 7 for samarium, europium, gadolinium, and dysprosium complexes, respectively) were determined by single-crystal X-Ray diffraction at temperature of -173 degrees C. A similar triclinic crystal system was observed for all complexes, and their cell parameters were determined. A new bridging mode between two metal centers was noted. In the Sm, Gd, and Eu structures, all tridentate bridging ligands were in the trans position relative to each other, while in the Dy structure, they were located in the cis position. These structural data were consistent with the thermal analysis, which showed that the removal temperatures of coordinated water differed. Specifically, the Dy complex exhibited the lowest removal temperature at 173 degrees C, followed by Sm and Eu at 184 degrees C, whereas the Gd complex displayed the highest thermal stability for coordinated water at 196 degrees C. Evaluating the structure and thermal stability of lanthanide complexes aids in the synthesis of materials with desirable performance characteristics.
