Energy transfer process in highly photoluminescent binuclear hydrocinnamate of europium, terbium and gadolinium containing 1,10-phenanthroline as ancillary ligand

Abstract

a b s t r a c tNew binuclear lanthanide (III) complexes of general formula [Ln 2 (hcin) 6 (phen) 2 ] (where Ln = Eu 1; Gd 2; Tb 3; hcin = hydrocinnamate anion; phen = 1,10-phenanthroline) were synthesized and fully characterized by elemental analysis, vibrational spectroscopy (infrared and Raman), thermal analysis (TGA/ DTA), CP/MAS 13 C NMR and powder X-ray diffraction. The crystal description based on powder X-ray diffraction data reveals that all compounds are isostructural and that each lanthanide ion is nine coordinated by oxygen and nitrogen atoms to form distorted tricapped trigonal-prismatic coordination polyhedron. The photoluminescence behavior was studied based on the excitation and emission spectra and luminescence decay curves. The emission spectra of Eu(III) and Tb(III) complexes are composed of intense and typical red and green emissions, respectively. Phosphorescence data of Gd(III) complex showed that the triplet states (T 1 ) of ligands have higher energy than the main emitting states of Eu(III) and Tb(III) indicating the possibility of intramolecular energy transfer for these metal ions. To elucidate the energy transfer process in the Eu(III) complex, spectroscopic properties as X k intensity parameters (k = 2 and 4), radiative (A rad ) and nonradiative (A nrad ) decay rates and quantum efficiency (g) of [Eu 2 (hcin) 6 (phen) 2 ] were determined. Such spectroscopic properties were compared with [Eu 2 (hcin) 6 (bpy) 2 ] complex properties recently reported. The high emission quantum efficiency (g = 72%) for Eu(III) complex 1 showed that it is a potential candidate as emitter in photonic systems.

Rare Earth-Indomethacinate Complexes with Heterocyclic Ligands: Synthesis and Photoluminescence Properties

“…This result suggests that RE-indomethacinate complexes are dinuclear or polymeric systems. Similar results were also observed for RE-ibuprofen complexes containing donor nitrogen ligands 36,37 and for RE-dipivaloyl complexes with tppo as neutral ligand. 38…”

Fluctuation of photon-releasing with ligand coordination in polyacrylonitrile-based electrospun nanofibers

“…6 with differential luminescence exhibited in the inserted photos, respectively. Upon different ultraviolet excitation, all spectra clearly resolve a broadband attributing to π-π * transition of ligands and emission lines of Tb 3+ 5 D 4 → 7 F J (J = 6, 5, 4 and 3) are obtained with the hypersensitive transition 5 D 4 → 7 F 4 (545 nm) green emission as the most prominent group [47][48][49][50] . However, the emission intensity is quite different for each complex, this difference originates from the various coordination environments caused by the diverse neutral ligands.…”

Synthesis, crystal structures, thermal decomposition mechanism and thermal properties of mononuclear ternry lanthanide complex with 2,4-dichlorobenzoic acid and 2,2′:6′,2″-terpyridine

“…率, 并且能够与稀土离子进行多样性的配位, 所以经 常作为第一配体与金属离子配位 [14] . 为了减少溶剂 分子参与配位所导致的荧光猝灭现象的发生, 第二 配体的选择也对配合物的研究起到至关重要的作用.…”