Preparation, Photo and Electroluminescence Properties of Novel Rare Earth Aromatic Carboxylates

Novel soluble rare earth aromatic carboxylates were prepared. The triplet energy level of organic ligand was measured. The photoluminescence properties of the Tb 3+ and Eu 3+ aromatic carboxylates and lifetimes were investigated, which indicated that these rare earth complexes have high quantum efficiency. Because of their excellent solubility, polymer-doping rare earth carboxylates were fabricated as thin films by spin-coating method and their luminescence properties were studied. Some rare earth organic light-emitting diodes were successfully fabricated which performed high pure color. The maximum luminance of the device of ITO/PVK/PVK∶Tb(AS) 3Phen∶PBD/PBD/Al is 32 cd·m -2 at 28 V.

Tetravalent Terbium Chelates: Stability Enhancement and Property Tuning

Coordination chemistry of rare-earth elements has been dominated by the+3 oxidation state.Complexes with higher-valence lanthanide ions are synthetically challenging but are of fundamental research interest and significance as advanced molecular materials.Herein,four tetravalent terbium complexes(2-5)of the common formula[Tb(OSiPh3)4L](L=ethylene glycol dimethyl ether(DME),2,2’-bipyridine(bpy),2,2’-bipyrimidine(bpym),and 1,10-phenanthroline(phen))are reported.Crystallographic analyses reveal in each of these complexes a hexacoordinate Tb(IV)ion situated in a distorted octahedral coordination environment formed by four triphenylsi-loxido ligands and a bidentate chelating ligand.The use of chelating ligands enhances the stability of the resulting complexes over their THF solvate precursor.More significantly,the aromatic N-chelating ligands have been found to tune effectively the electronic structures of the complexes,as evidenced by the sizable potential shifts observed for the quasi-reversible redox Tb(IV/III)process and by the changes in their absorption spectra.The experimental findings are augmented with quantum theoretical calculations in which the ligandπ-donation to the 5d orbitals of the Tb(IV)center is found to be primarily responsible for stability enhancement and the corresponding changes of physical properties observed.Magnetic measurements and results from electron paramagnetic resonance studies produced small absolute values of zero-field splittings of these complexes,ranging from 0.1071(22)to 1.1484(112)cm-1 and comparable to the values reported for analogous Tb(IV)complexes.

A ratiometric fluorescent nanoprobe based on ZIF-8@AuNCs-Tb for visual detection of 2,6-pyridinedicarboxylic acid

The rapid and sensitive detection of 2,6-pyridinedicarboxylic acid(DPA),one of the main biomarkers of Bacillus anthracis,is of great significance for the screening and diagnosing of anthrax.Herein,a ratiometric fluorescent nanoprobe based on zeolite imidazolate framework-8(ZIF-8)@AuNCs-Tb was constructed by embedding both gold nanoclusters(AuNCs)and terbium ions(Tb^(3+))into ZIF-8 for highresolution visual detection of DPA.Due to the aggregation induced emission enhancement(AIE)effect,AuNCs embedded in ZIF-8 emit a strong orange fluorescence.When Tb^(3+)is coordinated with DPA added to the nanoprobe,it will emit a strong green fluorescence owing to the antenna effect.The results reveal that ZIF-8@AuNCs-Tb nanoprobe can detect DPA effectively with a good linear relationship in the range of 40-200 and 200-1000μmol/L,the limit of detection(LOD)is estimated at 1.8μmol/L(3σ/k).The proposed nanoprobe shows a remarkable selectivity for DPA and is quite easy to realize visualization based on the fluorescent color changing from orange to green,which has potential application in clinical diagnosis.The feasibility of this method was verified by standard addition recovery experiments simulating the release of DPA from spores.

Unusual Luminescence of Ca_8[Al_(12)O_(24)](WO_4)_2: Tb^(3+)

The luminescence properties of aluminate sodalite Ca8[Al12O24](WO4)2 (CAW) undoped and doped with Tb3+ are reported and discussed. At room temperature the emission of tetrahedral 2-4WO in CAW showed an abnor-mally small Stokes shift (9060 cm-1), which is related to the crystal structure of CAW. A strong absorption band in the excitation spectrum of the Tb3+-activated CAW is ascribed to the absorption of the charge transfer state Tb4+- W5+, into which the excitation resulted in the efficient emission from the 5D4 level of Tb3+, but not from the 5D3 level.