Lanthanide-based luminescent hybrid materials.

Chapter 225 – Rare-earth beta-diketonates

Self-assembly of nanoscopic dodecahedra from 50 predesigned components

Out of the blue: semiconductor laser pumped visible rare-earth doped lasers

The nonsteroidal anti-inflammatory agents ketoprofen, tiaprofenic acid, suprofen and tolmetin, together with the anti-hyperlipoproteinemic drug fenofibrate and the anti-arrhythmic amiodarone can be included in the group of benzophenone-derived photosensitizing drugs. They contain a diaryl ketone chromophore and mediate the development of phototoxic reactions. In some cases, photoallergic responses have been reported. These properties have been substantiated in clinical reports, as well as by means of in vivo and in vitro assays. Tolmetin is phototoxic in vitro, however there are no reports on photosensitization by this drug in humans. In general, photochemical and photobiological studies strongly suggest that photosensitization involves formal hydrogen abstraction (either in a single step or via electron transfer followed by proton transfer) by the benzophenone-like chromophore from the excited triplet state. In the case of amiodarone, the radicals generated by photodehalogenation from the triplet are responsible for the photosensitivity side-effects.

Photosensitizing drugs containing the benzophenone chromophore.

Laser activity has been obtained from terbium tris (1, 1, 1‐trifluoroacetylacetonate) at room temperature in a liquid solution in acetonitrile and in p‐dioxane. Threshold pumping energy is about 1700 J. Characteristic line narrowing, spiking and beam collimation was exhibited.

LASER ACTION FROM TERBIUM TRIFLUOROACETYLACETONATE IN p‐DIOXANE AND ACETONITRILE AT ROOM TEMPERATURE

Photochemistry of Di(4-pyridyl) ketone in isopropyl alcohol

Photocyclization of di(2-pyridyl) ketone and 2-benzoylpyridine in aqueous solution

High-resolution emission spectra of several europium complexes with β-diketones, dipyridyl, and phenanthroline have been examined at 77°K in microcrystals. The Stark splitting of the 7F levels in the ground multiplet and the relative intensities of the individual 5D0→7F transitions can be used for theoretical correlation with the ligand field parameters, transition probabilities, molecular structure, and Eu-ligand bonding. The fluorescence spectra of the bis-aqua, tris, tris-aqua, tetrakis, and mixed chelates with the bidentate ligands are discussed in relation to molecular configuration.

Fluorescence spectra of homogeneous and mixed europium complexes.

The fluorescence spectrum of tetraethylammonium tetrakis(di-p-bromodibenzoylmethido)europate(III) was analysed in detail by treating the ligand field as a perturbation on the free-ion levels. From the splitting in the 7F1 and 7F2 levels of Eu3+ ion the ligand-field parameters were calculated without assuming a known molecular geometry and the structure suggested by these parameters is discussed. Comparison of parameter values of the p-bromo-substituted chelate with those of the unsubstituted dibenzoylmethide indicates that a substantial change in molecular geometry has occurred on replacing the para-H atoms with Br. Further, the experimentally derived parameters allowed calculation of interatomic distances and bond angles and suggested an increase in charge density in the vicinity of the lanthanide ion on p-bromo-substitution.

Analysis of fluorescence spectra of rare-earth chelates. Part IV. Effects of para-bromo-substitution on internal stark splitting and molecular geometry of tetrakis(dibenzoylmethido)europate(III)

Charles R. Hurt

Papers

LASER ACTION FROM TERBIUM TRIFLUOROACETYLACETONATE IN p‐DIOXANE AND ACETONITRILE AT ROOM TEMPERATURE

Photochemistry of Di(4-pyridyl) ketone in isopropyl alcohol

Photocyclization of di(2-pyridyl) ketone and 2-benzoylpyridine in aqueous solution

Fluorescence spectra of homogeneous and mixed europium complexes.

Analysis of fluorescence spectra of rare-earth chelates. Part IV. Effects of para-bromo-substitution on internal stark splitting and molecular geometry of tetrakis(dibenzoylmethido)europate(III)