Analysis of Fluorescence Spectra of Rare-Earth Chelates. II. Dipyridyl Complexes of Europic Chloride

Abstract

The emission spectra of two dipyridyl complexes of EuCl3 were analyzed in detail treating the ligand field as a perturbation on the free-ion levels. The ligand-field parameters were calculated from the splitting in the F71 and F72 levels of the Eu3 + ion without assuming a known molecular geometry and the model suggested by these parameters is discussed. In addition, the ligand-field parameters are used to calculate interatomic distances and to compare the coordinative properties of water and dipyridyl ligands. The method developed for deriving and verifying the geometrical arrangement and interatomic distances from fluorescence spectra proves to be a powerful tool.

Systematic Behavior of Charge-Transfer Transitions and Energy Level Variation in Soft Donor Complexes of the Trivalent Lanthanides

“…This is the case we observed for the Eu complex. No fluorescence was observed in laser excitation of Eu(Et 2 dtc) 3 (bipy), whereas most compounds containing Eu 3+ , including other dithiocarbamate complexes such as Na[Eu(Me 2 dtc) 4 ], and numerous 2,2‘-bipyridine-based complexes − are luminescent. The origin of this anomaly is well understood in the present case because the emitting state, 5 D 0 , is above the low-energy shoulder of the CT band.…”

Photovoltaic Cell Characteristics of Hybrid Silicon Devices with Lanthanide Complex Phosphor‐Coating Film

“…3 However, the thermal stability and mechanical strength of these lanthanide complexes are very poor compared with those of inorganic compounds often used as phosphors and laser devices. Furthermore, the emission intensity values are considerably lowered due to a multiphonon relaxation effect of excited energy via hydrated water molecules attached to these lanthanide ions in the complexes.…”

“…It is known that the photoactive lanthanide ions, such as Eu 3 + and Tb 3+ , form stable crystalline complexes with heterocyclic ligands, e.g., 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen), which exhibit excellent luminescence properties via efficient energy transfer from the coordinated ligands to the chelated lathanide ions. 3 However, the thermal stability and mechanical strength of these lanthanide complexes are very poor compared with those of inorganic compounds often used as phosphors and laser devices. Furthermore, the emission intensity values are considerably lowered due to a multiphonon relaxation effect of excited energy via hydrated water molecules attached to these lanthanide ions in the complexes.…”

Synthesis and luminescence properties of ZrO2 and ZrO2/SiO2 composites incorporating Eu(III)–phenanthroline complex prepared by a catalyst-free sol–gel process

“…Eu(phen) 2 (NO 3 ) 3 was conventionally prepared [14] by addition of the appropriate amount of phen ligand to an ethanolic solution of europium nitrate kept at about 60°C. After stirring for 30 min, the resulting white precipitate was filtered, washed several times with ethanol and dried in vacuum at room temperature.…”

“…Rare earth ions form with a great variety of heterocyclic ligands stable complexes which exhibit excellent luminescence properties attributed to the ''antenna effect'' [2,3]. This term, coined by J.-M. Lehn, denotes an efficient energy transfer from the triplet state of an absorbing coordinated organic molecule (the sensitiser) to a chelated RE ion (the activator).…”