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Accueil > Animation Scientifique > Année 2009

Pr. J.A. Gareth Williams

(Department of Chemistry, Durham University, UK)
 
Designing ligands for brightly luminescent platinum and iridium complexes : From light-emitting devices to bioimaging.







Mercredi 1er Juillet 2009 à 16h00

Salle Barriol (Entréee 2A, 7ème étage) Faculté des Sciences et Techniques

Contact : Yves FORT

Abstract  :

Light-emitting complexes of third-row transition metal complexes are potential phosphors in the new generation of display screen technology, based on organic light-emitting diodes (OLEDs). The synthesis and properties of brightly luminescent Pt and Ir complexes with cyclometallating terdentate ligands will be discussed. Palladium- and copper-catalysed cross-coupling reactions have been used to provide a range of ligands with diverse substitution patterns, to control the emission properties of the compounds. Complexes with exceptionally high quantum yields are possible, thanks to the rigidity of the structure and to the high ligand-field strength.

The Pt complexes form excimers at elevated concetrations, which emit efficiently in the red region of the spectrum. By combining this emission with the green-blue light of the isolated molecules, high-efficiency white-light-emitting devices are possible.

In the case of Ir, the combination of the cyclometallating ligand with co-ligands such as terpyridine and phenylpyridine leads to new families of complexes with a diverse range of luminescence efficiencies, rationalised on the basis of the relative energies of metal and ligand orbitals.

Several of these compounds also prove to be amenable to bioimaging in living cells, allowing unprecedented time-resolved and two-photon induced imaging on the microsecond timescale to be achieved.

 

Sous l’égide de la SCF Lorraine