Polyaryl Ether Dendrimer with a 4-Phenylacetyl-5-pyrazolone-based Terbium(III) Complex as Core:  Synthesis and Photopysical Properties

Abstract

A series of novel dendritic beta-diketone ligands, 1-phenyl-3-[G-n]-4-phenylacetyl-5-pyrazolone (n = 0-3, G stands for polyaryl ether), were synthesized by introducing Fréchet-type dendritic branches. The corresponding Tb3+-cored dendritic complexes were characterized by X-ray crystallography, elemental analysis, ESI mass spectra, and FT-IR spectra. These dendritic complexes, prepared from aqueous solution, exhibit high stability. Interestingly, the study of photophysical properties shows that the luminescence quantum yields of the dendritic Tb-complexes increase from 0.1 to 2.26% with an increase of the dendritic generation from 0 to 3. Importantly, an "energy-reservoir effect" was observed in the dendritic system using the method based on the resonance energy transfer from these complexes to rhodamine 6G. With the increase of the dendritic generation, the metal-centered luminescence quantum yield was almost the same, and the energy transfer (phi(transfer)) from the ligand to Tb(3+) increased. Further measurements of the triplet state and oxygen quenching of these dendritic complexes verify that this enhancement of the energy transfer (phi(transfer)) is attributed to both an "antenna effect" and a "shell effect".

3-Phenyl-4-aroyl-5-isoxazolonate complexes of Tb3+ as promising light-conversion molecular devices

“…The overall quantum yields of complexes 1 and 2 were calculated as 11% and 22%, respectively, and were found to be promising as compared to the recently reported Tb(PMIP) 3 (H 2 O) 2 (where PMIP = 1-phenyl-3-methyl-4-isobutaryl-5-pyrazolone; U overall = 29.7 · 10 À3 %) [16] and terbium-1-phenyl-3-[G-3]-4-phenylacetyl-5-pyrazolonates (G stands for poly aryl ether; U overall = 2.26%) [17]. Among complexes 1 and 2, the later shows better quantum yields due to the presence of electronreleasing group (-CH 3 ) on the benzoyl moiety.…”

Photophysical properties of a series of high luminescent europium complexes with fluorinated ligands

“…However, the Z sens values of 1-4 (solution and their Q tot shown in Table 3) are different though the S 1 and T 2 of diketone ligands of four complexes are almost identical. Complex 4 has the highest Q tot , which can be explained as the following: it has the longest fluorinated alkyl chains among 1-4, which produce a shell effect [30] (improved site isolation of the lanthanide center by the steric bulk of the bigger ligands) leading to a more hindered approach of the oxygen and other quenching effects to the energy transfer rate and the luminescent center in complex.…”

Synthesis, crystal structure, photoluminescence and semiconductive properties of a novel terbium complex

“…antenna effect. [12][13][14] We recently become interested in the crystal engineering of lanthanide coordination compounds with novel structures and interesting properties. We report in this work the hydrothermal synthesis, singlecrystal X-ray structure, photoluminescent and semiconductive properties of a novel terbium coordination compound, [Tb 2 (phenoxyacetic acid) 6 (H 2 O) 3 ] n •nH 2 O (1), which is characteristic of a two-dimensional (2D) layered structure.…”