Lanthanide ions possess fascinating optical properties and their discovery, first industrial uses and present high technological applications are largely governed by their interaction with light. Lighting devices (economical luminescent lamps, light emitting diodes), television and computer displays, optical fibres, optical amplifiers, lasers, as well as responsive luminescent stains for biomedical analysis, medical diagnosis, and cell imaging rely heavily on lanthanide ions. This critical review has been tailored for a broad audience of chemists, biochemists and materials scientists; the basics of lanthanide photophysics are highlighted together with the synthetic strategies used to insert these ions into mono- and polymetallic molecular edifices. Recent advances in NIR-emitting materials, including liquid crystals, and in the control of luminescent properties in polymetallic assemblies are also presented. (210 references.)

Taking advantage of luminescent lanthanide ions

The chemistry of heterocyclic carbenes has experienced a rapid development over the last years. In addition to the imidazolin-2-ylidenes, a large number of cyclic diaminocarbenes with different ring sizes have been described. Aside from diaminocarbenes, P-heterocyclic carbenes, and derivatives with only one, or even no heteroatom within the carbene ring are known. New methods for the synthesis of complexes with N-heterocyclic carbene ligands such as the oxidative addition or the metal atom template controlled cyclization of β-functionalized isocyanides have been developed recently. This review summarizes the new developments regarding the synthesis of N-heterocyclic carbenes and their metal complexes.

Heterocyclic Carbenes: Synthesis and Coordination Chemistry

Structure and nanostructure in ionic liquids.

Percent buried volume for phosphine and N-heterocyclic carbene ligands : steric properties in organometallic chemistry

Stereoelectronic parameters associated with N-heterocyclic carbene (NHC) ligands: A quest for understanding

Synthesis and structure of N-heterocyclic carbene complexes of uranyl dichloride

Criticality calculations for plutonium metal at room temperature in ionic liquid solutions

Coordination chemistry of the bis(trifluoromethylsulfonyl)imide anion: molecular interactions in room temperature ionic liquids

The optical absorption, emission, FT Raman, one-photon excitation, two-photon excitation, and luminescence lifetime measurements are reported for UO2Cl42- in 40:60 AlCl3−EMIC (where EMIC ≡ 1-ethyl-...

Spectroscopy of UO2Cl42- in Basic Aluminum Chloride−1-Ethyl-3-methylimidazolium Chloride

The redox behavior of uranyl (UOi\"^) has been examined in acidic AlClj-l-ethyl-B-methyl-imidazolium chloride (>50 mol% AICI3), a room temperature ionic liquid. Uranyl(VI) was reduced in bulk Solution by a chloraluminate species (AlCl^, AI2CI7, or AUClro) to produce U(V) chloride (UCl?). The kinetics of the reduction was investigated spectroscopically by monitoring the growth of spectral bands of U(V) chloride in the visible and near-IR regions of the spectrum over a five day period. Cyclic voltammetry of uranyl(VI) in acidic AICI3-EMIC at a scan rate of 100 mV/second indicated three reduction reactions occurred at the electrode surface corresponding to the U(VI)/U(V), U(V)/ U(IV) and U(IV)/U(ni) redox couples. At slower scan speeds (5 mV/second) only two reductive processes were observed which are assigned to the U(V)/U(IV) and U(IV)AJ(ni) redox reactions. Bulk coulometry of UO2CI2 in acidic AICI3-EMIC indicated an average 1.7 electron reduction producing a Solution which was verified spectroscopically to be U(rV). A possible mechanism for the behavior of uranyl(VI) in acidic AICI3-EMIC involves removal of the oxygens Itom UOi\"̂ in reactions with the solvent prior to the reduction, followed by reduction with AICI4. Uranyl(VI) is not a stable species in acidic room temperature ionic liquids.

David A. Costa

Papers

Synthesis and structure of N-heterocyclic carbene complexes of uranyl dichloride

Criticality calculations for plutonium metal at room temperature in ionic liquid solutions

Coordination chemistry of the bis(trifluoromethylsulfonyl)imide anion: molecular interactions in room temperature ionic liquids

Spectroscopy of UO2Cl42- in Basic Aluminum Chloride−1-Ethyl-3-methylimidazolium Chloride

Electrochemistry and Spectroscopy of UO22+ in Addic AlCl3-EMIC